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With the continuous increase of coal mining depth, the occurrence and prevention of deep rockburst in China have become normalized. In order to improve the effectiveness of deep rockburst prevention and control technology, starting from the technical difficulties of deep rockburst prevention and control in on-site engineering, combined with practical data statistics of disaster prevention and control engineering, this study demonstrates that the deep rockburst in China is due to its high geological stress and large range of human mining disturbance. The stress recovery of surrounding rock is fast after rock stress unloading during the disaster prevention and control process. The low effectiveness of rockburst prevention and control can be attributed to the new requirements of “three highs and one low” prevention and control technology in deep mining compared to that in shallow mining, including high-strength large-sized drilling to relieve pressure, in order to solve the collapse prone problem of thick and hard coal seams; small spacing high-density drilling to solve the problem of disconnected pressure relief range in drilling; multiple rounds of repeated high-frequency construction to solve the problem of rapid stress recovery after unloading pressure in deep coal seams; and the mining face is advancing at a low speed to solve the problem of high mining disturbance intensity. In response to the new requirements of “three highs and one low” prevention and control mode for deep rockburst, in order to further improve the safety and reliability of rockburst prevention and control, and based on the limitations of optimizing development and mining deployment for conventional source rockburst prevention and control, this paper proposes the technology of actively regulating the structure and load of overlying rock layers in the deep rockburst prevention and control areas, and presents some further scientific problems that need to be solved. Against the background of several typical rockburst accidents in recent years with the problem of “missed targets” in the prevention and control plans, a local targeted prevention and control technology for deep rockburst mining space has been developed, and the scientific challenges that need to be solved in the future have been pointed out. Against the background of the difficulty in evaluating safety issues after the implementation of coal mine rockburst prevention and control measures, a deep rockburst prevention and control unloading standard evaluation technology is proposed, and the scientific difficulties that need to be solved in the future are pointed out. The coal industry vigorously promotes intelligent mining, but the disaster control still relies on manual labor and personnel to operate in a high-risk environment. This paper also explores the emerging research direction and scientific challenges of intelligent mining and intelligent prevention and control of deep rockburst. Finally, it is objectively pointed out that the prevention and control of rockburst is not purely a theoretical and technical issue, and the human understanding of technical issues is also one of the important reasons for rockburst accidents. Combining with the on-site engineering practice, this paper discusses the concept and mechanism of rockburst, whether rockburst can be predicted, whether rockburst can be prevented and controlled, and how to deal with rockburst mines and other industry focused technical issues. It is pointed out that the problem of rockburst engineering is a struggle between humans and nature, which requires practitioners to objectively understand, objectively accept, and conduct in-depth research. The current achievement is of significance.

In order to improve the production of coalbed methane vertical wells in the central and northern Zhengzhuang block, southern Qinshui Basin, Shanxi, China, this paper analyzes the reasons for the poor stimulation effect of medium-deep coalbed methane vertical wells, based on the ground stress test data and fracturing monitoring data of these evaluation wells in the study area, proposes targeted stimulation techniques, designs and carries out field comparative pilot studies and analyzes their results. The results show that there are three main reasons for the low production of these vertical wells in the study area. Firstly, the vertical fracture is dominant, resulting in the shorter length of hydraulic fractures. With the increase of burial depth, the length and width of fractures decreases at the same fracturing scale. Secondly, with the increase of burial depth, the embedment depth of proppants into coal rock increases and the closure of hydraulic fractures speeds up. As a result, the stable production time is short, and the main form of gas production curve is “single peak” type. Thirdly, after the initial fracturing, the coal body structure is much more broken, and new fractures are easy to enter the initial fractures, which increases the difficulty of creating new fractures, resulting in poor stimulation effect. In view of the above reasons, the paper proposes an innovative technology of pre-plug, large-scale and remote-support re-fracturing. Pre-plug means that relatively low displacement, sand ratio and scale are first used to fill initial fractures, and then large-scale re-fracturing is carried out to create new fractures. Large-scale fracturing refers to the fracturing with large displacement, large fluid volume and high sand ratio. In order to improve the stimulation effect of middle-deep reservoirs, the fracturing fluid volume is increased from 600−800 m3 to more than 1 300−2 000 m3, the displacement is increased from 6−8 m3/min to more than 10−14 m3/min, and a low viscosity fracturing fluid system combined with low density proppants is used to increase the sand ratio from 7%−8% to more than 10%−15%. Remote-support is a combination of self-suspended proppants and large displacement to increase proppants migration distance and increase the proportion of the propped fractures. The average daily production of a single well reached 1 380 m3, which was 1 190 m3 higher than that before, and nearly 1 000 m3 higher than the stable gas production of adjacent wells, realizing the production breakthrough of vertical wells in the low-production area of the middle-deep reservoir in the north of Zhengzhuang block. Results of the comparative pilot studies showed that the average net construction pressure increased by 3.3 MPa after pre-plug, compared with the initial fracturing, which means that new fractures were formed and resulted in the production increase by 1 000 m3 compared with that of the wells without the Pre-plug. The pilot results show that, in general, the larger the technical parameters of pre-plug, large-scale and remote-support re-fracturing, the better the production performance.

This paper briefly summarizes the importance, current situation and existing problems of earthquake science popularization in primary and secondary schools, and focuses on the development path of earthquake science popularization based on STEAM education concept. On the basis of clarifying the main purpose, service target group of earthquake science popularization education, and effective popular science content and form, this paper applies the concept of STEAM education to propose the effective path of earthquake science popularization in primary and secondary schools. Taking the junior high school section as an example to make a specific case analysis, this paper suggests to build an earthquake science popularization ecosystem from the perspective of STEAM education. STEAM education is an interdisciplinary education concept that integrates science, technology, engineering, arts and mathematics, emphasizing the integration of disciplines. It is a new form of learning in which taking projects as the main line, teachers as the lead, and students as the main body. This study argues that STEAM education needs to be integrated into the earthquake science popularization, and a high-quality science education system should be constructed, covering both on- and off-campus educational activities and active learning ability, so as to create an ecosystem suitable for the development of science popularization education.

Objective Black carbon is a carbonaceous mixture formed by the incomplete combustion of biomass and fossil fuels. Since black carbon has a high carbon content and an aromatized molecular structure, it can persist in the natural environment, suggesting that black carbon is an important component of the global carbon cycle. Although pioneering studies have advanced the understanding of nature, circulation fluxes, and reserves of black carbon in the geosphere, it is still necessary to further clarify the source-sink processes of black carbon and explore the importance of black carbon in the global carbon cycle. Methods Here, this study reviews the available data on pathways, fluxes, and time scales of the global black carbon cycle and analyses and summarizes the migration mechanisms and constraints in the source-sink process of marine black carbon. Results This paper concludes that marine sediments serve as a large reservoir for black carbon, with a reserve of 569-1 380 Pg. Black carbon can persist over millennia in marine sediments, which is associated with a long turnover time as an "effective carbon sink" in the context of "carbon neutrality". Moreover, black carbon exerts a negative feedback effect on global warming due to its longer turnover cycle time than biomass carbon. The deposition of black carbon into the sea is an effective means to enhance carbon sequestration in the ocean and could be an effective way to implement the carbon capture, utilization, and storage (CCUS) strategy. Conclusion In this paper, we propose that human-induced production of black carbon from biogenic combustion may be actively regulated and that the deposition pathways and burial areas of black carbon into the sea should also be optimized given the premise of ecological and environmental friendliness based on a summary and assessment of the strategic value and climate significance of black carbon in marine sediments in the context of "carbon neutrality". Therefore, the positive role of black carbon in "negative ocean carbon emissions" can provide a basic theoretical framework for achieving the goals of "carbon neutrality".

Objective Palaeomagnetic methods can be used to quantitatively constrain the Early Palaeozoic palaeo-position of the North China Block (NCB), which provides a crucial scientific basis for researching the evolution of the Proto-Tethyan Orogeny and the affinity of the NCB for Gondwana. However, the NCB has undergone considerable tectonic activity since the Early Palaeozoic, and the Ordos Basin in the western part of the NCB is rich in hydrocarbon resources. Late tectonic activity and the migration of hydrocarbon resources may have caused remagnetization of Early Palaeozoic strata. Methods Thus, in this paper, to determine the main magnetic minerals in various rocks and their ability to record the primary remanent magnetization, we carry out a series of detailed petrography, rock magnetism and stepwise demagnetization experiments on the limestone and tuff samples of the Upper Ordovician Zhaolaoyu Formation in the Fuping area of the southern Ordos Basin, including optical microscope identification, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), saturated isothermal remanent magnetization (SIRM) acquisition curve, three-axis isothermal thermal demagnetization test, κ-T curve test, hysteresis loop experiment, first-order reversal curve (FORC), and thermal demagnetization and hybrid (TD+AF) demagnetization. Results The results indicate that the main magnetic minerals in the limestone and tuff samples are magnetite, pyrrhotite and/or greigite, and some samples also contain a tiny quantity of haematite with impurities and goethite. Mineral particles possess single domains (SDs) as well as multiple domains (MDs) within their magnetic domains. Combining petrographic and demagnetization data, this paper suggests that the main magnetic minerals in the samples are likely secondary minerals associated with later fluid alteration (maturation and migration of organic matter). Conclusion The remanent magnetic signals conveyed by these rocks cannot be directly used to constrain the Early Palaeozoic palaeoposition of the NCB but may be used to constrain hydrocarbon migration and accumulation in the Lower Palaeozoic strata of the southern Ordos Basin.

Objective Machine learning has been widely applied in the fields of collapse, landslide and debris flow susceptibility analysis. The selection of nonhazard samples is a key issue in landslide susceptibility analysis. Traditional random sampling and manual labelling methods may involve randomness and subjectivity. Methods In view of the potential randomness and representativeness of noncollapse samples, this paper considered soil collapse susceptibility evaluation a positive-unlabelled (PU) learning problem and proposes a two-step convolutional neural network framework (ISpy-CNN) that combines an information value model and the Spy technique. First, 15 collapse-related factors were selected for modelling based on the geomorphological, geological, hydrological, and artificial environmental conditions of the study area. Low-information-value samples that were able to map the distribution structure of noncollapsing samples were screened by the information value model. Then, through the Spy technique and training the CNN model, negative samples with high confidence were identified from low-information-value samples that were classified as noncollapsed samples. Finally, based on the framework and traditional random sampling, we used support vector machine (SVM) and random forest (RF) models to compare and verify the reliability, prediction accuracy and data sensitivity of the proposed learning framework and other models. Results The results illustrate that the proposed ISpy-CNN method can improve the accuracy, F1 value, sensitivity and specificity on the validation set by 6.82%, 6.82%, 6.82%, 8.23%, respectively compared to random sampling and 2.86%, 2.89%, 2.86%, 2.31%, respectively compared to the traditional Spy technique. The prediction accuracy of step 2 in PU learning using the CNN model is higher than that of the RF and SVM models. The sample set screened by the ISpy-CNN framework exhibited greater stability, prediction accuracy and growth rate than those screened by the traditional Spy technique by adding the same number of training samples. Conclusion The ISpy-CNN framework proposed in this paper can better assist in the selection of nonhazard samples and real collapse spatial distribution maps, and the results of the framework are more consistent with the actual collapse distributions.

Coal has made important contributions to the industrialization process of human society, and has played a key supporting role in ensuring China’s energy security and stable economic development. Since the mid-19th century, the coal-based fuel of coal, kerosene, gas and coal electricity has gradually entered the era of large-scale use. However, the traditional use of coal produces high carbon emissions, which has become a major problem in energy transition. Facing the development of ecological civilization society, the clean and efficient use of coal is imminent, and the innovation of modern coal-based energy technology is imperative. This paper proposes the definition and connotation of modern coal-based energy technology system, which is defined as the production of low-carbon energy products such as coal-based gas, coal-based oil, coal-based hydrogen and coal-based electricity, and the in-situ absorption of carbon dioxide in mining areas to form a clean and low-carbon energy production system with carbon neutrality. Its technical connotation includes coal-based gas, coal-based oil, coal-based hydrogen, coal-based electricity and dynamic carbon neutrality in mining areas, with a total of 5 technical modules, 19 technical units and 61 key technologies. The modern coal-based energy technology system will play an important role of “one main body, three supports and one breakthrough” in the future new energy system. Coal-based electricity provides the main body of electricity system stability. Coal-based oil supports the China’s oil safety. Coal-based gas supports the China’s gas safety. Coal-based hydrogen plays a supporting role in the development of hydrogen energy in China. The major breakthrough is the dynamic carbon neutral technology of coal-based energy. The paper supposes that when the ratio of non-fossil energy and low-carbon coal-based energy is maintained in the range of 2.5−3.0, coal-based energy, oil and gas and wind, water, nuclear energy can be reasonably integrated to form a new quality energy system with strong complementarity, high reliability and low carbon emissions. Based on the major breakthrough and practical application of modern coal-based energy technology, it is predicted that China’s low-carbon coal-based energy production will reach 1.02 billion −1.46 billion tons of standard coal equivalent (tce) in 2060, equivalent to 18%−24% of the national energy demand, and carbon dioxide emissions will be controlled below 500 million tons. Compared with the current energy transformation planning path based on “de coal” planning, the share of coal in our energy system can increase from 10% to more than 20%, and carbon dioxide emissions will reduce by 50%. At that time, the modern coal-based energy system has great technological innovation significance for China’s energy security and carbon dioxide emission reduction, and helps China to become a country with independent energy supply.

During the coal mining process, the change in the floor stress state of coal seam will produce deformation and failure. The seam floor failure in different coal mining processes has a certain law. At present, the water disaster monitoring of coal seam floors based on the DC resistivity method mainly focuses on the resistivity response characteristics of floor deformation and damage. To investigate the temporal changes in the electrical properties of the coal seam floor during mining, this study employs the inter-hole DC perspective observation system and the time-lapse resistivity reflection coefficient method. Through numerical simulation and field tests, the study uncovers the temporal variation law of the resistivity of coal seam floor induced by mining activities. First, this paper compares the results of individual inversion and time-lapse resistivity change rates for a typical geoelectric model to validate the reliability of the inter-hole DC perspective time-lapse method. Next, considering the mining-induced damage to the coal seam floor, this paper analyzes the electrical response patterns and charac-teristics of the rise of confined water and the damage zone in the floor during the mining process. It also discusses the feasibility of using a time-lapse resistivity reflection coefficient to assess the depth of coal seam floor damage, offering a theoretical basis for field construction. Finally, , the on-site monitoring tests reveal the electrical change characteristics of coal seam floor during the coal mining process. The time-lapse resistivity reflection coefficient R is utilized to determine the damage depth of the rock layer of the working face floor, which is found to be 15 m. The study results demonstrate that the time-lapse characteristics of the resistivity of coal seam floor mining damage obtained by the inter-hole DC perspective method can mitigate the influence of formation factors and random noise in the monitoring data to a certain extent. Additionally, the time-lapse resistivity reflection coefficient can be utilized to determine the depth of coal seam floor failure. This method transforms the detection target from the single study of geological anomalies to the full life cycle dynamic monitoring of the floor damage of the working face in the process of coal mining and then realizes the detailed depiction of structural damage to the working surface floor.

Based on the green development trend and requirements of China’s coal industry, this paper analyzed the factors that coal mines consider in choosing filling mining methods and the constraints that affect the promotion of filling mining technology. According to the geographical distribution characteristics of different mining areas and the differences in filling demands, four types of priority principles of “protecting the ecological environment, protecting surface buildings, addressing coal gangue and solid waste, and improving economic efficiency” for coal mine filling mining were defined. The ecological mining goal of “building the whole process holographic intelligent ecological mine by adopting filling mining as a regulation tool to protect the ecological environment in coal mines” was put forward. Based on the finite deformation mechanical model of the roof in filling mining, the factors affecting the subsidence of target rocks in filling mining were expounded, and the supporting strength calculation and overburden deformation control equations under three filling engineering modes such as ecological environment protection, ground building protection and gangue treatment were established. In addition, the paper introduced the development status and direction of universal filling technology in coal mines in China, including solid filling of raw gangue waste, modified solid filling, gangue concrete filling, integrated mining-filling-charging, large amount of gangue filling, filling method in thin coal seam, filling method for regional protection, filling method in continuous mining roadway and other filling technologies that meet various needs of coal mines. The material preparation and transportation of different filling technologies, the characteristics of filling process and the adaptive filling equipment were described in detail. In order to realize the intelligent filling of coal mines, a comprehensive data perception system was established, which realized the intelligent process from unit to whole filling working face through spatial planning and filling effect judgment. The sensor network and artificial intelligence algorithm were combined to monitor and control the solid filling process of coal mine in real time, and improve the filling quality and filling efficiency. Coal mine filling mining will play a more important role in the long-term planning of China’s green mine construction. Strengthening the scientific and technological research of the whole process of coal mine production based on active filling, the construction of universal filling technology and process system, the development of new solid filling materials, and the research of intelligent filling mining, will help the filling mining technologies in China’s coal mines have a very broad prospect.

The MILD combustion is a combustion mode that occurs in a moderate or extremely low oxygen environment, combining the advantages of high combustion heat utilization and very low NOx emissions, and is considered by the international combustion field to be one of the cleaner combustion technologies with great potential for application. Since the relevant research began around 1990, the technology for achieving a MILD combustion of gas fuels has been relatively mature, while the research on the MILD combustion mechanism and implementation conditions of solid fuels such as coal powder and biomass is still relatively lacking. Based on the high momentum oxidizer jet, internal recirculation is achieved, eliminating the need for external high-temperature preheating to establish MILD combustion, greatly expanding the application range of MILD combustion. This paper provides an overview of the basic characteristics of MILD powder fuel combustion from the aspects of particle dispersion, heating, ignition, combustion, and pollutants. Due to the uneven dispersion and reaction of particles, the MILD combustion process of carbon-based solid fuels such as coal powder is more complex than that of gas fuels. High speed jet MILD combustion not only increases ignition delay but also expands ignition and reaction zones, requiring systematic research on the characteristics and mechanisms of each combustion stage. This paper introduces the research achievements in the theoretical design and equipment development of solid fuel MILD combustion. It is recommended to improve the existing coal-fired boiler burner, adjust the process parameters to match the MILD combustion mode, increase the residence time of coke particles to improve combustion efficiency, improve combustion stability, and suppress various pollutant emissions, including fine particulate matter, through high-precision numerical simulation. Based on the overall approach of interconnected energy systems, the coupling research between MILD combustion and various new combustion technologies should be promoted, especially strengthening the research on the co-combustion characteristics of coal powder, biomass and hydrogen, ammonia and other combustible gases, and assisting in energy transformation. Exploring the characteristics of turbulent two-phase flow, turbulent interphase heat transfer, and turbulent chemical coupling in the powder MILD combustion is crucial for deepening the understanding of powder MILD combustion. It involves multivariate analysis and high-precision simulation, which will be the focus and difficulty of future research.

The safe, green, efficient and low-carbon coal mining is the common goal of surface coal mines around the world. The development intensity and ecological carrying capacity of surface coal mine resources in China show the reverse development characteristics, and the vulnerable ecological environment areas in northwest China have become the main surface coal production areas, which makes surface coal mining and ecological environment protection become important scientific problems, ecological problems and development problems to be solved urgently. On the basis of the development situation, natural conditions and main influencing factors of surface coal mines, the connotation characteristics and overall structure of realizing the safe-green-efficiency-low-carbon mining of surface coal mines were explained. Aiming at the characteristics of the whole life cycle of pre-mining, mid-mining and post-mining of surface coal mines, in terms of four levels: safe mining technology, green mining technology, efficient mining technology and low-carbon mining technology, this paper puts forward eight key technologies including the time-limited slope control technology, the intelligent early warning decision-making technology, the new mode of transportation link, the ecological construction of mining area, the coordinated mining of adjacent mines, the intelligent mining design, the application of electric mining trucks and the ecological damage reduction at mining sources. The key work and direction of safe-green-high efficiency-low carbon cooperative mining in surface coal mines are clarified. In terms of the measures of safety-green-efficiency-low carbon co-development, regarding strengthening a top-level design, accelerating the distributed implementation, enhancing key researches, promoting personnel training, and improving standards and regulations, the paper proposes the target tasks to be accomplished in different stages in 2025, 2030 and 2035. In the new era, surface coal mines should firmly follow the development path of safe-green-high efficiency-low carbon, and realizes the high-quality development goal of surface coal mines.

Coal mining machine is the core equipment of completely automated working face, and the research and development of intelligent coal mining robot is crucial for achieving the intellectualization of fully mechanized working face. This paper comprehensively analyzes the current research status of sensing detection, position and attitude control, speed control, cutting trajectory planning, and tracking control in the coal mining machine roboticization process, and proposes five key technologies that must be solved in the development of intelligent shearer robots, including sensing and detection, pose control, velocity control, cutting trajectory planning and tracking control. Aiming at the problem of intelligent perception, this paper proposes the construction thought of a coal mining robot intelligent perception system, as well as the architecture of a coal mining robot intelligent per-ception system. The architecture of the intelligent perception system for coal mining robots is outlined, enabling a comprehensive sensing of running state, posture, environment, and so on, thereby ensuring the safe and reliable operation of intelligent coal mining robots. In terms of the position and attitude control problem of intelligent coal mining robots, the intelligent PID position and attitude control thought is proposed, along with an improved genetic algorithm-based PID pose control method, enabling precise pose control for the coal mining robot. As to the problem of velocity control, the thought of cutting load measurement based on the fusion of “force-electricity” heterogeneous data is proposed. Additionally, a neural network-based algorithm for cutting load measurement is presented, achieving an accurate load measurement. Furthermore, a traction and cutting speed adaptive control approach is proposed, including an artificial intelligence-based decision-making method for traction and cutting speed and a sliding mode control method for traction and cutting speed with disturbance rejection. This approach enables a precise and adaptive speed control for the coal mining robot. Regarding the problem of cutting trajectory planning and tracking control, the precise cutting trajectory planning thought is proposed, incorporating geological data and historical cutting data into a cutting trajectory planning model. The precise cutting trajectory tracking control thought is proposed, and an intelligent interpolation algorithm-based cutting trajectory tracking control method is given, achieving a high-precision trajectory planning and accurate tracking control for the coal mining robot. Considering the “position-attitude-velocity” collaborative control problem, the intelligent optimization idea of "position-attitude-velocity" collaborative control parameters is proposed, which utilizes an improved particle swarm optimization method based on multi-system constraints to optimize the coordinated control parameters, resulting in intelligent and efficient operation of the coal mining robot. The in-depth investigation of these five key technologies for intelligent coal mining robot provides some valuable insights for accelerating the development of high-performance, efficient, and reliable intelligent coal mining robot.

In view of the intelligentization of coal mine roadway excavation, this paper discusses the current development status of four major categories of intelligent fast excavation equipment, including continuous mining machine, excavation and anchor machine, full-section excavation system, and anchor excavation machine, analyzes the applicability of the four major categories of intelligent fast excavation equipment with the geological conditions, proposes some key technological issues for the realization of intelligent coal mine excavation which need to be resolved, and also explores the information transmission and intelligent analysis technology, intelligent perception technology, precise positioning and navigation technology, autonomous stereotyped directional cutting technology, remote and autonomous cutting control technology of road-header and multi-level and multi-process intelligent cooperative control technology, as they are the basis for the realization of intelligent roadway excavation. Based on the key technological issues needed to be solved in the mine roadway excavation under the complex geological conditions, the paper puts forward the design method of systematic analysis, modular design and optimal combination of functions, according to the functional requirements of the excavation operation and the requirements of the excavation process. A multi-level digital twin architecture of virtual control and virtual-reality combination is studied based on the multi-dimensional information reproduction of heading equipment, environment, and geological structure to realize the remote control of road-heading machine. A control method that integrates single-machine intelligence, system synergism, and synergism of underground intelligent control and surface remote monitoring is proposed. A new type of flexible advance support technology without repetitive crushing, multi-stage telescopic cutting technology of cutting section, and multi-rig parallel operation technology of intelligent anchoring unit have been developed, and a new type of combined unit for rapid roadway heading operation with a parallel operation of excavating, supporting, anchoring, transporting, and exploring processes has been also developed, and a flexible parallel operation technology of excavation robot, advance support robot, anchoring robot, and auxiliary transportation robot group has been proposed. A data-driven multi-machine, multi-process collaborative control behavior planning and decision-making method is proposed. In addition, it is proposed to construct a complete coal mine underground cross-system full-temporal-spatial information digital sensing system, build a data sensing intelligent monitoring platform with multi-parameter, multi-scale and full-temporal-spatial characteristics, that integrates the production state of underground site, spatial information of roadway, state of heading equipment, and risk information, etc., and realize a real-time communication between virtual system and actual tunneling system, so as to realize the intelligent and less-manned heading through data-driven planning and analysis.

The safety in the coal-producing mines in China is continuously improving, but coal and gas outburst accidents still occur. The prediction of coal and gas outbursts allows the scientific application of outburst prevention measures, which can ensure the safe coal mining to a certain extent. Machine learning is an interdisciplinary field involving probability theory, statistics, and computer science, which can explore the nonlinear relationship between outburst accidents and its associated indicators. The application of machine learning in coal and gas outburst prediction has received relatively widespread attention, and with the rapid progress of artificial intelligence and computer technology, it will play a greater role in the field of outburst prediction. Therefore, this paper provides a comprehensive review of the research on machine learning in coal and gas outburst prediction, analyzes the difficulties in outburst prediction and prospects its development direction. Firstly, the paper provides a brief overview of the research status on the hypothesis, occurrence mechanism, and prediction index selection of coal and gas outbursts. Then, it summarizes the research progress in the field of outburst prediction, including the application of support vector machines, neural networks, extreme learning machines, and ensemble learning algorithms. In addition, it also points out the existing problems in the current research, such as imbalanced samples, missing data indicators, and small sample sizes. Finally, the paper gives an outlook on the developments of coal and gas outburst prediction based on machine learning, including improving algorithm performance, optimizing feature engineering, and increasing sample size. With the continuous improvement of computer performance, more powerful models may be proposed, which can further improve the prediction accuracy of outburst accidents.

The fragile ecological environment in the western coal mining areas of China, compounded by intensive mining activities, has led to water and soil erosion, soil degradation, and damaged root systems. With a low plant water use efficiency, the ecological restoration becomes challenging, making the improvement of water use efficiency a key aspect in the ecological restoration or reconstruction of western mining areas. Soil water is a critical factor limiting the ecological restoration of arid and semi-arid coal mining areas, as it connects atmospheric water, surface water, groundwater, and vegetation growth, serving as an important carrier for water circulation and nutrient transport. Efficient and rational utilization of soil water is crucial to the success of ecological restoration. Therefore, investigating plant root water utilization strategies plays a significant role in the ecological restoration of western coal mining areas. This paper analyzes the main research methods of plant water use at home and abroad, compares the advantages and disadvantages of different methods, and reviews the corresponding research progress. In the damaged ecological environments of arid and semi-arid coal mining areas, the application of plant-microbe combined microbial remediation technology can improve plant water use efficiency and enhance plant water use strategies. At the same time, the microbial inoculation reduces the proportion of water absorption by plants from shallow soil layers, effectively increasing the absorption and utilization of water from deep soil layers by plants, thereby enhancing plant water use efficiency. This enables the inoculated plants to exhibit a higher ecological adaptability in the arid and semi-arid coal mining areas. This paper analyzes the current research progress and existing problems of plant water use in the western coal mining areas, discusses the improvement of water use strategies through microbial remediation in mining areas, and proposes the impact of different plant combinations on water use strategies and their research focuses in the ecological restoration of western arid coal mining areas. This lays a solid foundation for achieving green, sustainable, and high-quality development in the arid and semi-arid coal mining areas, and has important ecological application value.

This paper collected the data of death and loss of contact in Luding MS6.8 earthquake, quantitatively analyzed the characteristics of the number of deaths and loss of contacts over time, and compared with typical destructive earthquakes in recent 10 years. Combing the actual emergency rescue work, this paper sort out and summarized the main reasons, systematically analyzed the impact of geological disasters on personnel mortality and loss of connection rate, discussed the characteristics of earthquake disasters and disaster relief in mountainous areas. At the same time, we propose suggestions for the verification and submission capabilities of earthquake disaster information and the improvement of personnel search and rescue capabilities in complex mountainous environments.

Objective Landslide dams are a geological body of key concern for engineering construction in alpine canyon areas. This paper takes the Dalongchi landslide dam in the South Tianshan Mountains as the research object to explore the origin and evolution process of the landslide dam in alpine canyon areas of the South Tianshan Mountains. Methods Based on satellite remote sensing images, regional data, field investigation, and geological drilling data in the Dalongchi region, combined with theoretical calculations and finite element discrete element simulations, this paper systematically delved into the deposit characteristics and the formation and evolution process of the Dalongchi damming body. Results The results show that (1) Many landslide scratches and grooves can be seen on the steep mountain surface on the North side of the Dalongchi damming body, of which the packing structure has obvious inverse grading features and a jigsaw structure, and it is speculated that the formation may be caused by the accumulation of the high-speed and long-distance ancient landslide of Dalongchi. (2) By conducting the recurrence of the northern original surface of the Dalongchi landslide and theoretical calculation and numerical simulation on its kinematic characteristics, the results were then induced that there was a high-speed and long-distance landslide on the north side of the mountain that led to the formation of the damming body of Dalongchi. (3) The formation and evolutionary phases of the Dalongchi damming body can be divided into the embryonic stage of ancient landslides, the river-blocking forming stage of the damming stage by ancient landslides, and the overlapping stage of ancient damming bodies. Conclusion The study of the formation and evolution of the Dalongchi dammingbody can provide a reference for the subsequent genetic analysis of similar studies in the southern Tianshan region.

Landslide disasters occur frequently in Fujian Province, and early warning of landslide disasters on a regional scale is an important means of effective disaster prevention and mitigation. Due to the complex mechanism of landslide disasters, the traditional regional landslide early warning methods have such problems as insufficient accuracy. Deep learning mainly refers to the technology of feature extraction, abstraction, representation and learning by constructing the neural network model, which is a kind of machine learning. As a classical deep learning algorithm, convolutional neural network has more powerful classification and representation ability than traditional machine learning. Taking Fujian Province as the research area, this paper introduces the convolution neural network into the field of landslide disaster early warning and constructs a regional landslide early warning model of Fujian Province. The process is as follows: (1) The SMOTE optimization algorithm is used to optimize the sample database of landslide disasters in Fujian Province from 2010 to 2018, enlarging the number of positive samples and expanding the proportion of positive and negative samples from 1∶3.4 to 1∶2, and the total number of samples reaches 18040. (2) Construct a convolution neural network model structure, which includes an input layer, two convolution layers, two maximum pooling layers, a full connection layer and an output layer. (3) Use the convolution neural network to train the optimized samples (80% of the samples from 2010 to 2018 as the training set), and use the Bayesian optimization algorithm to optimize the model parameters to obtain the regional landslide early warning model of Fujian Province. (4) The model is tested with 20% of the samples from 2010 to 2018 as the test set, and the confusion matrix and ROC curve are used to test the model. The results show that the accuracy of the model ranges from 0.96 to 0.97, the AUC value is 0.977, indicating that the model accuracy and generalization ability are good. (5) The actual situation of the landslide disaster in the flood season of 2019 is taken as a positive sample, negative samples are collected through the method of time-space sampling, and the 2019 regional landslide sample verification set (603 samples) is constructed. The model is further verified by using the confusion matrix and ROC curve. The results show that the accuracy of the model ranges from 0.75 to 0.85, and the AUC value is 0.852. Although only the actual landslide samples in the flood season of 2019 is used for verification, good results is also achieved. In this paper, the convolution neural network algorithm is applied to the regional landslide early warning, which provides a new way to establish the regional landslide early warning model. The preliminary verification shows that the model is effective and will be further applied and verified in Fujian Province in the future.

The eastern margin of the Tibetan Plateau is composed of multiple secondary tectonic units which constitute typical “multi-level extrusion-rotation active tectonic system”. It is the tectonic transformation belt that regulates the eastward extrusion of plateau blocks, and contains high-density active faults. This area is characterized by frequent and high intensity strong earthquakes and complex geological and geomorphological features. Therefore, this region is one of the areas in China where the problem of earthquake disaster is particularly significant. In recent years, with the research deepening of the national earthquake disaster risk survey, active fault detection of urban，seismic experimental site construction, seismic safety evaluation of engineering sites, identification of active faults and evaluation of crustal stability in major projects sites and urban areas，and the wide application of high-precision remote sensing, tectonic geomorphology, paleoseismic and Quaternary chronology methods. The investigation of seismogenic structures around the eastern margin of the Tibetan Plateau and its adjacent areas has been significantly improved. In order to timely exchange the latest study results in this field support regional earthquake prevention and disaster reduction and geological safety evaluation of important projects sites and infrastructure construction, the journal editorial department of Progress in Earthquake Science organized the special topic “The strong earthquakes and seismogenic structures in eastern margin of Tibetan Plateau and adjacent areas”. More than 20 representative academic papers such as active faults and earthquakes, Jishishan earthquake in Gansu Province，and research reviews in related fields have been collected. In this issue, 10 papers are selected in the special topic I “The strong earthquakes and seismogenic structures in eastern margin of Tibetan Plateau and adjacent areas”. It is hoped that these newly study results may improve the understanding of characteristics of strong earthquake activity and seismogenic structural mechanism in the region, and provide scientific basis for regional strong earthquake risk analysis and effective prevention of strong earthquake disaster risk.

Daqingshan piedmont fault is located in the northern margin of Hetao basin and has been active strongly since the Late Quaternary. Previous researchers had conducted extensive research on the characteristics of paleoseismic in this area, but limited by the dating techniques and the fact that there were fewer data available on the same fault profile that can effectively constrain paleoseismic events, and fewer profiles that can reveal more paleoseismic events. This paper explores the excavation of an paleoseismic trench on the east side of Lianhuashan in the western section of Tuyouqi of the Daqingshan piedmont fault, using Optically Stimulated Luminescence data, and combineing with the age data of previous exploration trenches. By using the fault successive limit method, it is found that the western section of the Tuyouqi fault has experienced five paleoseismic events approximately 11500 years ago, with an average recurrence interval of 2260 years. The five paleoseismic events in this section of the fault, from new to old, are 1.28 to 1.42 ka, 3.41 to 3.60 ka, 4.08 to 5.01 ka, 8.26 to 9.32 ka, and 10.70 to 11.30 ka, respectively. The latest event of activity should be the earthquake of 849 AD. Meanwhile, the trench exploration revealed that the fault in this section exhibits a normal fault nature, with an inclination angle between 58 and 77 degrees. According to empirical formula, the potential seismic capacity of the Baotou section, the western section of Tuyouqi, and the western section of Tuzuoqi are around MW6.8～7.1, MW6.8～7.1 and MW7.1～7.2, respectively. The magnitude obtained by the empirical formula in this paper is relatively small, and there may be cascade rupture. In the later stage, it is necessary to conduct a comprehensive evaluation of the risk of the western section of Daqingshan piedmont fault combined with other means.

The epicenter of the 2017 Qinghai Zeku MS4.9 earthquake was located near the SN-striking Riyueshan fault, while the focal mechanism solutions and the dominant arrangement of seismic sequence are inconsistent with the Riyueshan fault. In this paper, we have discovered EW- and NW-trending faults near the epicenter, by methods of remote sensing interpretation and field investigation. These faults are western terminal structures of Xiahe fault, in which the EW-trending faults are north-dipping and associated with kinematics including both left-lateral and vertical slip. Meanwhile, we use double differential positioning to relocate seismic sequences of Zeku MS4.9 earthquake. Results show that seismic arrangements consist of two segments striking NW and EW. The seismic profile crossing EW-striking segment indicates a north-dipping fault plane. Well consistence is found between Xiahe fault and seismic arrangements of Zeku MS4.9 earthquake, which leads us to the speculation that the seismogenic fault of Zeku earthquake is Xiahe fault. From a regional perspective, the Xiahe fault might be one strand of dissipating faults in the western end of the West Qinling fault, and the Zeku MS4.9 earthquake represents tectonic activity of the western end of the West Qinling fault. Besides，the northwestward turn of fault striking and reverse slipping of Xiahe fault might also be attributed to the right-lateral shearing effects of Riyueshan fault. Results of this paper highlight the significance of improving active fault traces, especially for the secondary or pre-existing faults in a tectonic active area.

Lacustrine sediments store a wealth of information and are often used to indicate climate change. Natural disasters such as earthquake, flood, landslide or collapse usually form characteristic disturbances in lacustrine sediments, which can be analyzed and identified using lake geology methods. This paper reviews the research progress of lacustrine sediments, systematically summarizes the characteristics of typical natural disasters in lacustrine sediments, and focuses on the identification methods of natural disaster events in lacustrine sediments. Among them, the comprehensive analysis method integrates various analysis methods for sedimentary identification of lake events at the present stage. ① Identify the endogenous and exogenous origin based on the relationship between sedimentary facies and event-induced deposits(EID)；② Recognize the most likely trigger based on the elimination of impossible triggers；③ Verify the correctness of the most likely trigger according to the existing identification criteria. This method integrates the advantages of typical mark analysis and exclusion method, and is the most effective analysis method at present. This paper also discusses the advantages, disadvantages and constraints of the study of lacustrine sediment disaster events. The continuity, sensitivity and high resolution of lacustrine sediments are conducive to the study of disaster events, but the establishment of sedimentary identification markers of typical natural disaster events in lakes is still the key to restricting the study of lake abnormal events in the future.

The North Mountain landslide in Lijie Town has been in a long-term creeping deformation state and has experienced multiple landslide and debris flow disasters. Monitoring the surface deformation of landslide to grasp the surface deformation pattern of disaster body is a reliable basis for realizing early warning prediction of geological disaster. In this paper, a machine learning model is introduced to predict the relevant data, and a long and short-term memory network is used to predict the landslide deformation by monitoring the displacement data of North Mountain in Lijie, and the prediction results are compared with the actual data and analyzed. In this paper, root mean square error , mean absolute error , coefficient of determination and explainable variance are used to evaluate the prediction results, among which the coefficient of determination and explainable variance reach 0.99. It shows that the long short-term memory network used in this paper achieves good prediction performance in the prediction of landslide deformation in the North Mountain of Lijie.

The Erzhuangke landslide is a typical landslide affected by the rainy season. Rainfall changes the seepage pattern with the pre-existing landslide, weakening matric suction and soil shear strength, leading to the formation of tension cracks internally. This triggers overall sliding and localized extensive deformations. Existing studies seldom considers the interaction between the seepage field and stress field of the Erzhuangke landslide. Therefore, based on the actual engineering geological disaster scenarios, supported by on-site monitoring data and terrain physical parameters, a geometric computational model is established, and hydraulic coupled numerical simulations are conducted. By investigating variations in saturation and pore pressure within the landslide, the paper explores the rainfall infiltration patterns. It examines the impact of rainfall intensity on landslide reactivation from the perspective of stress displacement. In addition, in order to validate the accuracy and feasibility of the method, selected measurement points from the landslide are matched with corresponding positions in the numerical model. Comparative analysis is performed on displacement, soil pressure, and saturation aspects, confirming that the numerical model effectively reflects the actual situation. Through coupling numerical simulations and the study of the reactivation mechanism of the old landslide under rainfall conditions, the paper interprets field data, analyzes the reactivation process, and provides theoretical foundations and technical guidance for subsequent engineering early warning and disaster mitigation works.

Objective 3D geological modelling is a kind of technology that converts multisource geological data into 3D geological models through computer. It reveals the spatial distribution relationship between various underground geological bodies, which helps geologists understand underground geological structures more intuitively, providing certain support for resource exploration, disaster prediction, engineering construction.However, complex geological environment, scarcity of effective geological data, large amount of calculation and other factors make the construction of large-scale complex geological bodies become an urgent problem to be solved in the development of 3D geological modelling. Methods To address these issue, this paper proposes a large range of complex geological body block modelling methods. Based on the model horizontal distribution scope of bounding box, large range of research area will be divided into several relatively smaller ones to perform modelling. At the same time, virtual borehole and stratum partition automatic tracking algorithm will be introduced for the block model at the bottom, top and middle part for the consistency of boundary constraints.At the same time, when modelling each block, the range of modelling data is extended to ensure that the strata between merged blocks can achieve smooth transition at the boundary of block. Results Each block of model is combined into a complete one with coherent and smooth stara so that a large range of complex three-dimensional geological body modelling can be realized. Conclusion Taking the shallow underground model of the Xiamen Maluan Bay New urban area as an example, this paper constructed corresponding geological model to test the modelling effect. The model is dissected and compared with the real borehole. The feasibility of proposed method is verified in terms of modelling efficiency, continuity and smoothness of strata connection.

The central and western coal resources have the highest degree of enrichment and superior development conditions in China. With the improvement of mining efficiency, the disturbance of high-intensity and large-mining-height mining mode to groundwater system also increases. In particular, the groundwater in the aquifer outside the disturbance range of the water-conducting fracture zone gradually participates in the mine water inflow process during the coal mining. Such mode leads to a series of problems such as large deviation of mine water inflow prediction, inaccurate evaluation of water inflow risk and unclear water hazard prevention measures, which brings great hidden risks to the current mine water hazard prevention and control. In this paper, a derivative mode of dynamic water inrush is summarized. With the coal mining, the evolution of groundwater system caused by overburden failure will induce new disaster sources, resulting in different forms of water inrush. Its connotation is to change the basis of defining the derivative dynamic water inrush model from the traditional static analysis before mining to the dynamic evaluation considering the change in the whole mining cycle. The derived dynamic water inrush model of the mine can be preliminarily divided into three categories, namely, “skylight leakage type”, “bed separation disaster type” and “channel permeability increase type”. This paper mainly discusses the derivative dynamic water inrush mode of “skylight leakage type”. Taking the Shanxi Yushen mining area, a shallow buried coal seam mining area with high strength and large mining height, as an example, the disaster-pregnant conditions of “skylight supply type” derivative disasters are discussed in depth. Through supplementary analysis of water-richness and hydraulic connection strength of indirect water-filled aquifer, the comprehensive evaluation of water inrush risk in roof aquifer is achieved, and the evaluation method system of disaster derivative model is put forward. Through the transformation of mining mode, the active prevention and control system is constructed. A passive prevention and control system is constructed by multi-objective advance drainage before mining and local grouting after mining. By further refining the mine water inrush disaster model, optimizing the evaluation system and establishing comprehensive prevention and control technology, it provides a scientific basis for the protection of groundwater resources and safe low-carbon mining in ecologically fragile areas.

In order to improve the modern management level of unattended seismic monitoring stations in cities and counties, standardize the management of observation logs in stations, and improve the display of seismic monitoring work in cities and counties, Jiaxing Seismic Survey and Prevention Center actively explored the implementation of digital management of seismic monitoring stations through the development of the “Digital Observation Log Project of Seismic Monitoring Stations”. This paper mainly introduces the basic ideas and technical approaches of the research and development of the project, and briefly describes the main functions of the system. The implementation of the project can effectively solve the drawbacks of the traditional paper-based observation logs of seismic monitoring stations, and realize the digital management of the basic information of seismic monitoring stations and daily operation and maintenance. The project also builds the QR code for station information, effectively giving full play to the role of city and county monitoring stations in science popularization and publicity in earthquake prevention and disaster reduction, emergency response, disaster prevention culture and other aspects, and expanding the social service function of stations.

Objective With the development of drilling technology for deep strata, the study of the dynamic characteristics and parametric response law of drill bits and deep complex strata during drilling has become a key and difficult point in research. Methods In this paper, a combination of numerical simulation and response surface analysis was used to study the dynamic characteristics of PDC bits and typical complex strata in the drilling process, and parametric analysis was carried out. In this paper, soft-hard-staggered strata with dip angles as a typical complex formation were studied, the dynamic damage finite element simulation model between the PDC drill bit and the soft-hard-staggered strata with the full real size was established based on Abaqus, and the dynamic characteristics of the drill bit subjected to the reaction force of the strata during drilling were derived. Numerical simulation experiments were also conducted by orthogonal tests to investigate the dynamic characteristics of the PDC bit under different formation parameters and drilling parameters. Results The single factor analysis and response surface analysis were used to model and identify the relationship between drilling parameters and stratigraphic parameters and the reaction force on the drill bit by the stratum and to obtain the changing trend and regression model of the reaction force on the drill bit by the stratum under multiple parameters. The results showed that the higher the inclination angle of soft-hard-staggered strata, the higher the average value and peak impact value of the bit subjected to the stratigraphic reaction force. The larger the ratio of softness to the hardness of the strata is, the larger the average and peak reaction forces on the drill bit. Within a certain range, increasing the rotational speed will reduce the impact of the reaction force on the drill bit. Conclusion The research results provide a basis for predicting the bit reaction force during drilling in deep and complex formations and guide the control of the drilling trajectory in deep and complex formations, which is of great significance for deep geological drilling.

Objective Recently, the seismic damage of an actual bridge structure in a frozen soil area has shown that the presence of frozen soil will increase the lateral stiffness of the bridge foundation, which may cause more serious seismic damage to the bridge structure, but there is a lack of research on the frozen soil-pile interaction effect of frozen soil bridge structures under seismic loadings and the corresponding seismic responses. Methods The present paper proposed efficient nonlinear numerical models to consider the effect of the frozen soil-pile interaction on the seismic responses of structures. First, the relationship between the depth of frozen soil and surface temperature was constructed. Then, the p-y spring modelling approach was presented to simulate the seismic behavior of frozen soil. Several as-recorded ground motions were selected as the seismic input. The seismic responses of piers and bearings of regular bridges with different depths of frozen soil under seismic loadings were investigated. Results The results show that the proposed efficient nonlinear numerical model can be adopted to model the seismic behavior of bridges considering frozen soil. And the proposed p-y curves for frozen soil can accurately predict the p-y relationship from the existing tests. When the PGA is relatively small, the pier curvature increases slightly; by contrast, in the case of large PGA, frozen soil can significantly increase the curvature demands, which can make the pier enter into the inelastic behavior. When the depth of frozen soil is small (the temperature is -5℃), the bearing displacement increases significantly, which increases the probability of unseating under seismic loadings. Moreover, frozen soil can transfer to the adverse locations of structural systems under seismic loadings. Conclusion Therefore, the conclusions of this paper can provide the necessary theoretical basis and data support for studying the seismic performance and corresponding seismic design methods of frozen soil bridge structures in China, which is of great significance for promoting the development and engineering application of disaster prevention and mitigation of bridge engineering in frozen soil areas in China.

The Lower Cambrian Qiongzhusi Formation in Sichuan Basin and on its periphery is rich in shale gas resources, and it has become one of the important shale gas development intervals in Sichuan Basin. Controlled by complex sedimentary setting, the silty shale reservoir in Qiongzhusi Formation has various lithofacies and strong heterogeneity longitudinally, which restricts the exploration and development of shale gas. Therefore, it is urgent to study the sedimentary characteristics, sedimentary facies and sedimentary models. Based on the previous understanding of tectonic setting and sequence stratigraphy, and through detailed analysis of rock data, well logging data, geochemistry data and paleontology data, this paper clarifies the Early Cambrian sedimentary background of combined ocean-paleoland influence, moderate water depth and widespread reduction of Sichuan Basin and its periphery. The paper also believes that the Qiongzhusi Formation is mainly deposited in shore facies and continental shelf facies. The continental shelf facies are dominated, including shallow water continental shelf subfacies and deep water continental shelf subfacies. Based on the analysis of the combined action of wave and tide, seawater evaporation, suspension, rising ocean current, sedimentary paleogeomorphology and other fine-grained sedimentary influencing factors, and combined with the spatial distribution characteristics of sediments, the fine-grained sedimentary model of the Lower Cambrian Qiongzhusi Formation in Sichuan Basin and on its periphery is established, i.e., in the early stage of sedimentation, the effect of differential sedimentation is significant, the sequence thickness varies greatly, and the sedimentary characteristics and influencing factors differ greatly in different regions. In the middle stage of sedimentation, the effect of differential sedimentation is diminished and the difference of sequence thickness decreases continuously. In the late stage of sedimentation, with steady sedimentation, it enters the "open basin" stage, and the sequence thickness tends to be consistent.

As an important biological element, nitrogen is causally linked with organic matter accumulation, but a systematic and regular understanding has not been developed. This paper discusses this issue by taking the widely developed Permian-Paleogene terrestrial (lacustrine) hydrocarbon source rocks in China as an example. The results show that the terrestrial source rocks in China can be classified into three groups according to the nitrogen isotope (δ15N) compositions and combined with the salinity and evaporative alkali mineral characteristics: the circum-neutral group 1 (average δ15N=4.0‰±1.5‰), the circum-neutral group 2 (average δ15N=7.1‰±1.6‰), and the alkaline group (average δ15N=18.4‰±3.3‰). In the circum-neutral group with δ15N < 10‰, the δ15N of the source rocks is positively correlated with organic matter abundance, type, hydrocarbon generating capacity and shale oil potential due to the fact that higher δ15N characterizes changes in the composition of the hydrocarbon generating bio-precursors. In the alkaline group with δ15N>10‰, the organic matter types are good and shale oil potentials are higher, but the response relationship between δ15N of source rocks and organic matter accumulation is not as good as that of the circum-neutral group, reflecting that the organic matter accumulation in alkaline group is influenced by other comprehensive factors other than δ15N. Accordingly, the organic matter accumulation models of three types of lacustrine source rocks (< 5‰, 5‰-10‰, and >10‰) classified on the basis of δ15N were established. The δ15N has the potential to trace organic matter accumulation and quality of source rocks. For example, low δ15N type (δ15N < 5‰) is of poor quality and medium-high δ15N type (δ15N>5‰) is of good qualityin lacustrine source rocks. This paper enriches the biogeochemical and hydrocarbon source rock geochemical studies of nitrogen by exploring organic matter accumulation in source rocks from the new perspective of nitrogen isotope composition and nitrogen cycling.

The Junggar Basin is rich in oil and gas resources, with huge exploration potential, which is one of the main arenas of increasing oil and gas reserve and producing in China. In recent years, CNPC has made major breakthroughs in exploration in the Junggar Basin, revealing the orderly symbionic distribution pattern of conventional and conventional oil and gas. In order to further learn from the oil and gas achievements and exploration and development experience in neighboring areas and the new geological theories, for formulating SINOPEC's oil and gas exploration strategy in the Junggar Basin, the potential and distribution characteristics of the oil and gas resources in the Junggar Basin are systematically analyzed in this paper and it is pointed out that no enough attention is paid to natural gas and unconventional petroleum. The key breakthrough direction and exploration strategy of SINOPEC in the Junggar Basin are put forward in the paper after reviewing the major exploration breakthroughs in multiple fields, multiple strata, and multiple types in recent years and combining with the oil and gas geolo-gical conditions and exploration practice of SINOPEC's mining rights area. The research reveals that the Junggar Basin has entered a new period of exploration dominated by the middle and lower assemblage, and the exploration ideas must be adjusted accordingly. We must insist on the transformation from early outside-source exploration to intra-source and near-source exploration, and from early conventional petroleum exploration to both conventional and unconventional petroleum exploration. In order to make big exploration breakthrough of SINOPEC and realize the target of increasing reserves and production in the near and medium term in the Junggar Basin as soon as possible, four exploration strategies are proposed in the paper, including further figuring out the resources, establishing an integrated research team of conventional and unconventional petroleum, strengthening the joint research of geological and engineering integration, and increasing the support of risk exploration.

Kaolin is a common clay in engineering. The microstructure of kaolin is very sensitive to the change of pore environment. At present, the research on the relationship between pore environment characteristics and acoustic wave velocity of kaolin remains to be further studied. In this paper, based on the ultrasonic test theory, RSM-SY6 ultrasonic detector is used to study the change rule of ultrasonic wave velocity of kaolin under different pore environment conditions. In addition, the influence mechanism of pore environment characteristics on ultrasonic wave velocity of kaolin is analyzed from the microscopic perspective of the arrangement mode of clay particles and the interaction between clay particles and pore solution. The results show that (1) the ultrasonic wave velocity of kaolin decreases with the increasing void ratio. (2) With the increasing water content, the ultrasonic wave velocity of kaolin decreases slightly at first and then increases greatly. (3) The effect of pore solution pH value on ultrasonic wave velocity of kaolin is related to the edge isoelectric pH value. When the pore solution pH value is equal to the edge isoelectric pH value, the ultrasonic wave velocity is the maximum. (4) The addition of salt reduces the ultrasonic wave velocity of kaolin. When the concentration of saline solution ranges from 0 to 0.5 mol/L, the wave velocity decreases rapidly. Under the same anion condition, the high valence cation has a more obvious effect on the reduction of ultrasonic wave velocity. This paper provides a reference for the study of the acoustic characteristics of viscous soil, and also provides a theoretical basis for the application of ultrasonic detection technology in soil.

Remarkable achievements have been made in groundwater management in China since the implementation of the strictest water resources management system. Groundwater has been restored to some extent. By the end of 2020, the shallow groundwater level generally showed an upward trend in the Northeast China Plain, the Huang Huai Hai Plain and the Middle and Lower Yangtze Plain, and the decline rate of deep groundwater level was slowed down. Only 291 monitoring stations have an average annual decrease in groundwater level of over 2 m, accounting for 8.7% of the total national monitoring stations. However, there are still many problems difficult to solve, mainly reflecting in some areas where the groundwater level continues to decline, the balance between mining and replenishment has not yet been reached, and land subsidence still occurs. Meanwhile the effectiveness of over-exploitation area management has not been as significant as expected. In this paper, we first briefly review the progress and obtain achievements of strict groundwater management and groundwater over-exploitation area treatment in our country. Then we discuss the main problems faced by groundwater management in China, e. g., unclear delineation of hydrogeological conditions, inadequate accuracy of groundwater monitoring and measurement, inconsistency between groundwater management objectives and current technics, immature external conditions for groundwater management, and difficulty in groundwater ownership registration. The targeted countermeasures are put forward, mainly including strengthen the study of groundwater circulation and transformation from the perspective of watershed or regional water balance, strengthen the research and pilot of groundwater double-control indicator determination method, further strengthen the groundwater monitoring and mining output measurement and statistics, and further clarify the responsibilities of groundwater management. The determination method of groundwater dual-control management index is demonstrated. It is proposed that the quantitative relationship between groundwater exploitation and groundwater level should be clarified, based on the resources, geological environment, and ecological environment functions of groundwater level to determine water level control indicators, and the reasonable dual-control index should be determined considering the actual demand, groundwater management objectives, precipitation years and other conditions. This paper deeply think about the probable problems of strict groundwater management and groundwater over-exploitation treatment in China, and the solving ways of the problems is also proposed. It can provide a basis for sustainable utilization and scientific management of groundwater in China

On 26 June 2023, a catastrophic debris flow occurred in the Banzi Catchment in Wenchuan county of Sichuan province. This debris flow event is a viscous debris flow triggered by short duration heavy rainfall. The volume of debris which transported out of the catchment by debris flow is more than 8.3×105 m3, and the debris flow blocked the Minjiang River. The river blockage formed a barrier lake with an area of about 0.4 km2. To reveal the formation mechanism of the occurrence of the extremely large debris flow events 15 years after the Wenchuan earthquake, This paper adopts a comprehensive method of field investigation, image interpretation, topographic superposition and calculation of forced vortex. This paper also analyzes the formation mechanism of debris flow and the characteristics of river blocking. Based on the results, this paper gives some suggestions of investigation and prevention of debris flow in the Banzi catchment. The research results show that (1) the triggering rainfall is characterized by short duration and high intensity. The main initiation positions are in the channel. The main debris supply is from the debris deposition along the channel. (2) The peak discharge of debris flow is as high as 755.5 m3/s, which is the main cause of river blockage. (3) Since the Wenchuan earthquake, the debris flow activity of the Banzi Catchment has the characteristics of lag and long-term because of the coupled transport of debris on the slope and along the channel. (4) The volume of the debris source which can be eroded along the channel should be paid more attention in subsequent investigation and prevention. The research results are helpful in better understanding of the activity evolution of the post-seismic debris flow. They can also provide scientific references for the prevention of the post-seismic debris flow..

Areas with different levels of susceptibility to landslides, rainfall warning thresholds vary widely, to improve the pertinence and accuracy of landslide monitoring and early warning. Based on field geological survey and landslide susceptibility condition analysis, this paper combines information quantity model and analytic hierarchy method to carry out susceptibility evaluation, and then analyzes the correlation between landslide occurrence probability and cumulative rainfall, and conducts landslide rainfall early warning threshold model research by zoning. The results showed that: Slope, elevation, geological structure, engineering rock group and water system are the main geological conditions of landslides in Longling County; The area of non-prone areas in Longling County was 14.33 km2, the area of low prone area was 1053.87 km2, the area of medium prone area was 1471.65 km2, and the area of high prone area was 254.73 km2; The rainfall warning time was determined for a single day and the previous 3 days, and the rainfall warning threshold was refined by district; Compared with the rainfall warning threshold model applied to the landslide monitoring and early warning in Longling County, the number of early warning information decreased by 70, the accuracy of early warning was increased by 14.4%, and the effective early warning of landslide in Shijiazhai Formation of Huba Village, Zhen’an Town was realized. This paper provides a good reference method for determining the regional landslide rainfall warning threshold.

This paper uses various channels to collect the data of earthquake disasters in 2022, and collates the global seismic activities and earthquake disasters in 2022. The change curves of global disaster earthquake frequency and casualties in recent 20 years and the distribution map of disaster earthquakes in 2022 were drawn. By summarizing the earthquake information and disaster conditions causing casualties, a detailed analysis of major earthquake disasters was made. The main characteristics of global earthquake disasters in 2022 were summarized, and major earthquake events in Afghanistan were listed. Compared with last year’s earthquake, the number of casualties caused by earthquake disasters in 2022 has decreased, and the disaster earthquakes are characterized by concentrated casualties and frequent secondary disasters. In view of the prominent causes of earthquake casualties, this paper puts forward corresponding earthquake disaster prevention measures and suggestions.

Objective Monitoring natural attenuation (MNA) is a widely used, economical and effective remediation technique for soil and groundwater contamination. The migration of nonaqueous phase liquid (NAPL) in heterogeneous strata is an important element in the assessment for the efficiency of MNA. Methods Based on three consecutive years of dynamic groundwater quality monitoring data, the purpose of this study is to accurately characterize the biodegradation processes of multiphase fluids at a typical phenol contaminated site in northern China. A multiphase flow numerical model of phenol transport considering Monod biodegradation processes based on TOUGH3/TMVOCBio software was developed and applied. The model depicted the spatial distribution and temporal variation of phenol under the current conditions well and analysed the sensitivities of the adsorption and biodegradation parameters. The paper also discussed the removal contributions of dissolution, volatilization, adsorption and biodegradation effects under uncertainty of adsorption and microbial degradation parameters and predicted two different natural attenuation scenarios for source disposal. Results The contribution of phenol removal varies over a range under the influence of parameter uncertainty, with 17.91% to 58.02% for biodegradation, and precipitation conditions affect the seasonal variation in phenol concentrations. In the future 20 years, under the conditions with complete removal of the phenol source and the present leakage model, the total mass removal rate of phenol will arrive at 98% and 80% at the end of the 20th year, respectively. Conclusion This paper identifies the biodegradation parameters with high sensitivity in the multiphase flow model, which provides a reference for the numerical simulation of the organic matter biodegradation process at petrochemical sites and can also provide a theoretical basis for the application of MNA technology in China.

Objective In order to understand groundwater systems, it is useful to study the changing characteristics and mechanisms of hydrogeological parameters with time. Responses of groundwater level microfluctuations to natural periodic loadings, such as earth tides and barometric pressure, serve as low-cost and effective investigation technique to calculate aquifer hydrogeological parameters. Methods In this paper, we systematically reviewed theoretical methods of hydrogeological parameters estimation based on groundwater level response to earth tides, barometric pressure, and their combination. We presented earthquake-related and mining-related parameters change with time in well-aquifer system. The barometric pressure response method also applies to the assessment of aquifer vulnerability. Results We conclude that studying the microfluctuation of groundwater level may provide insight into the interaction among hydrogeological processes, tectonic activities, and artificial influences in the shallow crust at spatial and temporal scales. Conclusion This paper also proposes three scientific problems to be solved in the future: the application of skin and wellbore storage effects, the improvement of computation accuracy of hydrogeological parameters by combining multiple methods for determining basic geological parameters, and the investigation of other artificial influences such as groundwater overdraft and subsidence to regional aquifer systems.

While giving full play to the role of coal energy security supply, it is an important proposition related to national energy security and overall development to realize green and safe mining and clean and low-carbon utilization of coal resources. This paper analyzes the influence of changes in the international development environment on the China’s utilization of oil and gas resources in the international market, and studies the rigid demand for energy supply in China. Based on the current situation of energy development and utilization with coal as the main energy source in China and following the fundamental requirements of building a harmonious modernization between man and nature, this paper puts forward the green and low-carbon development direction and path of coal industry in the process of realizing the goal of “dual carbon”. ① China’s external dependence on oil and gas resources exceeds 70% and 40% respectively, and its strategic reserves are insufficient. Under the background of profound changes in the international situation, the uncertainty of using oil and gas resources in the international market increases, and the external risks of national energy security have increased. ② Building a modern country will inevitably lead to the rigid growth of energy demand. At present, it is difficult for new energy sources to replace fossil energy safely and effectively, and the main energy position of fossil energy will be difficult to change in the short term. ③ Comparing with the “dual carbon” goal, the proportion of coal consumption before the peak shows a continuous downward trend, and the total consumption will usher in an inflection point. After the peak, the main energy position of coal will be weakened, but the role of strategic mineral resources and coal-based raw materials will be further highlighted. ④ Driven by the goal of “dual carbon”, the basic national conditions with coal as the main energy source determine that coal will continue to undertake the important mission of energy security supply and further play the role of strategic mineral resource as raw material. However, the high carbon resource attribute of coal determines that the development and utilization of coal will face the dual pressures of ensuring supply and reducing carbon emissions. Therefore, in order to serve the high-quality economic and social development, which requires security and green and low-carbon energy supply, it must be based on the current characteristics of energy production and supply with coal as the main energy source and new energy as the supplement at this stage, and take the new progress of ecological civilization construction as the fundamental principle. The research on the key technologies should be enhanced such as the technologies of coal mining and ecological carbon sink, CO2 geological storage in deep coal seams and coal mined-out areas, and collaborative development and utilization of new energy in coal mining areas, which will support the high-quality development of the China's coal industry with technological innovation under the goal of “dual carbon”.

Radon is sensitive to the change of strata stress before and after the earthquake. It is an effective element for tracing the structure and seismic activity, and accounts for a large proportion in China’s earthquake precursor observation network. In recent years, due to the aging and updating of instruments, the calibration of radon meters at many stations has been restricted, which further affects the accuracy and reliability of radon observation data. In this paper, the high-precision AlphaGUARD radon meter is used to calibrate the BG2015R radon meter in Ningde No.1 well by using fresh well water and fixed sources with a certain concentration. The relative errors between the new K value and the old K value are 2.83% and 1.1% respectively, and the calibration results meet the observation requirements of China Earthquake Networks Center; At the same time, the average and consistency of the measured values of AlphaGUARD radon meter and BG2015R radon meter in the calibration experiment are calculated and analyzed, and the value suggestions for the calibration of the two sets of instruments are given. The flow and method of the calibration experiment described in this paper can provide a certain technical reference for the calibration of the radon meter operating in the network.

At present, the creep problem of underground engineering surrounding rock still exists, and the creep theory needs to be further enriched. In essence, rock creep is a process of constant accumulation of damage. In view of the damage evolution of rock under creep conditions, triaxial creep tests are carried out on red sandstone taken from Yibo Tunnel in Leshan, Sichuan Province by TAW-2000 to analyze the creep deformation rule of specimens under different confining pressures. Based on Weibull distribution and Perzyna viscoplastic theory, an improved viscoelastoplastic creep model is established which can describe the whole process of rock creep failure. The critical point damage variable is defined by dividing the creep stage, so that the acceleration creep start time can be determined more accurately. The following conclusions are drawn: (1) the model curve in this paper is in good agreement with the test data, which verifies the accuracy and rationality of the model in this paper, and indicates that the viscoelastic-plastic creep model of red sandstone established based on Weibull distribution is feasible. (2) Based on Perzyna viscoplastic theory, a more accurate viscoplastic strain expression is established to describe accelerated creep. (3) The triaxial damage creep model established in this paper based on Weibull distribution and Perzyna viscoplastic theory can describe the whole process of rock creep well, overcoming the shortcoming of the Siyuan model which can not describe accelerated creep. The relationship between rock creep deformation and damage can be better reflected by defining the critical point damage variables of different creep stages, which enriches the creep constitutive theory of rock materials.

Prediction of water inflow of a sub-sea tunnel under the blasting vibration effect is still a difficult subject. This paper takes the sub-sea tunnel between the Wawuzhuang Station and Guizhou Road Station of the Qingdao Metro Line 1 as the engineering background. Based on the equivalent continuum model, the mirror image method is used to deduce the calculation formula for the water inflow of the sub-sea tunnel considering the damage area factor. Through forward modeling and inversion, combined with numerical simulation results and actual engineering monitoring results, the correctness of the formula is comprehensively verified, and the influence mechanism of damage area factors on water inflow is analyzed. The results show that the squeezing effect caused by blasting vibration makes the pore water pressure of surrounding rock around the tunnel rise rapidly in a short time. After reaching the peak value, it began to decline slowly with the weakening and disappearance of blasting vibration. Under the influence of damage zone factors, the water inflow of the tunnel increases gradually with the increasing thickness of the damage zone, but it will not increase continuously with the increase of the coefficient of permeability in the damaged area. Through numerical simulation calculation, the ratio of tunnel water inflow considering blasting damage area is 1.4, and the error is only 4.1% compared with the calculation result of 1.342 deduced in this paper. The calculated results in this study are only 0.53 m3/(d·m) less than the field measured results, and are closer to the measured results than those with the traditional calculation formula, indicating that the calculation formula in this paper is suitable for the calculation of tunnel water inflow considering the factor of damage zone, and are of high engineering application value.

Under the action of the Earth’s inner dynamics, the lithosphere shapes different types of the Earth’s surface, and the crustal stress state and its dynamic change law are captured by the comprehensive observation technology of drilling crustal activity. It is an important way for human beings to understand the internal dynamic process of the Earth and study the mechanism of inner dynamic geological hazards. The contribution of developed countries such as Japan, the USA, and the IODP International Cooperative Research Program to the development of integrated borehole crustal observation technology is summarized in this paper. The paper also systematically reviews the development history and present situation of borehole strain observation technology and borehole strain observation instrument in China. Especially since the 13th Five-Year, under the background of the national strategy of deep-sea exploration, the China Geological Survey Bureau (CGS), the China Earthquake Administration, and other systems have successively carried out research and development of the integrated geophysics observation system in wells, and have been put into use in integrated land and sea observation stations. The Institute of Geomechanics has successfully developed an integrated geophysics observation system for crustal activity using the key techniques of system integration. The system has a variety of strain, tilt, seismic, geomagnetic, geothermal, pore pressure, other sensors, and 16 components capable of observing crustal deformation, stress, strain, tilt, earthquake, and their induced geodynamic changes in the lithosphere, such as geotemperature, hydrology, geoelectricity, geomagnetism, etc. It has been put into use in Shandan (installed depth 253 m) and Pingwu (WFSD-4, 1600 m) observatories in Gansu and Sichuan provinces and has achieved initial results. It is a milestone for our comprehensive crustal activity observation technology to break through the 3000-meter-deep well in the future. It can provide vital information for geodynamics research, safe exploitation of deep mineral and geothermal resources, and prediction of internal dynamic geological hazards. At the same time, based on the national strategy of deep-sea exploration in the 14th Five-year, the future development direction of integrated observation system of deep-well crustal activity is pointed out.

Based on geological surveys and experimental data, numerical modeling of metallogenic dynamics (NMMD) establishes a mathematical model (mathematical-physical equation) that quantitatively characterizes metallogenic processes using the basic laws of mathematics, physics and chemistry. Then, using the finite element or finite difference method, the model is built through efficient computer calculation, simulating the metallogenic dynamic process and its metallogenic response, revealing metallogenic law and guiding prospecting. NMMD integrates theories and methods of geology, mathematics, physics, chemistry, computers and other disciplines and has distinct characteristics of interdisciplinary integration. In recent years, driven by the rapid development of computational science and mathematical geology, important progress has been made in NMMD. This paper summarizes the basic theories and methods of NMMD, compares the characteristics of four metallogenic numerical simulation software programs, and introduces the development and application status of NMMD with progress of the author′s team in the past decade. The main conclusions and understandings are as follows: ①Multi-field coupled metallogenic dynamics numerical simulation is the only feasible method to reproduce the large-scale complex metallogenic process. With the rapid development and improvement of high-performance computing technology and nonlinear dynamics theory, it becomes one of the research hotspots and development directions of modern mathematical geoscience. It is important to reveal the metallogenic mechanism and obtain mineral exploration information, which has great potential for development; ②At present, there are some limitations in NMMD, such as uncertain simulation parameters and incomplete coupling of multifield processes, which will be the focus of its future development. Numerous studies have been devoted to solving these problems; ③Under a new paradigm of scientific research driven by big data, a combination of NMMD and machine learning can effectively invert the metallogenic process and quantitatively predict mineral resources. This method is an important breakthrough in the application of NMMD in deposit genesis and mineral exploration. This paper clarifies the basic methods and key problems of NMMD in promoting the study of deposit genesis and exploration, and expounds the frontier direction of NMMD, which provides basic guidance for the study of computational modeling of metallogenic dynamics.

Natural gas hydrate is a kind of clean energy with great development potential but is still not commercially developed due to the bottlenecks such as exploitation technology, economical efficiency, and environmental effects.In recent years, people have explored the application of hydrate technology in the field of CO2 capture, seawater desalination, energy storage, gas separation, etc. One of the most challenging and critical problems is how the hydrates are formed and decomposed at any time. This paper summarizes the fundamental research on hydrate decomposition dynamics, including hydrate decomposition properties, influencing factors, and dissociation mechanisms. Moreover, the paper reviews the development of hydrate dissociation dynamics models. The existing models are divided into four categories according to dissociation mechanisms: Thermal dissociation models, intrinsic dynamics models, mass transfer dissociation models and integrated models, and their assumptions, main understanding and limitations are highlighted. Future directions for improving hydrate dissociation dynamics research are foreseen to deepen the understanding of hydrate dissociation dynamics and promote the development and utilization of hydrates.

It is necessary to plat the multiple-map sheet data sets into a single map when processing the geochemical data from the entire map sheet and compiling a large-scale geochemical map, but step effects might readily arise where different map sheets converge. There are currently few papers that compare and optimize various methods, and most systematic error-related studies focus on a specific way to correct and assess the step effect of geochemical data in a particular area. With the map sheet from the Yuanyi, Bajiabielichier, Goulixiang, and Zhiyi in Gouli region of Qinghai Province as a case study, this paper applies the framing standardization method, normalized method, and contrast method to perform systematic error correction and method optimization on 1∶50 000 stream sediment geochemical data and provides the effective method reference for the systematic error processing of the geochemical prospecting data of the rock cuttings. The results indicate that these three methods have distinct effects on systematic error correction.After the original data are corrected, the background difference between adjacent map sheets is basically eliminated, the step effect is effectively weakened, the geochemical zoning is continuous, the strong anomalies are appropriately suppressed, and the weak anomalies are appropriately enhanced and represented in the background. After the same element is corrected with various methods, there are differences in the anomalous area, form of anomalies, and goodness of fit with the mineral deposit (point). The goodness of fit between anomalies and known deposits (points) after correction with the framing standardization method and normalized method is 75%; the anomalies are evenly distributed throughout the region, but individual ore-induced anomalies are weakened, and the influence of invalid anomalies cannot be avoided. The nonmineral anomaly in the high background area can be effectively suppressed by the contrast method, and the mineral-induced anomaly in the low background area can be strengthened. The anomaly's goodness of fit with the deposit (point) is 87.5%, the invalid anomaly's influence is minimal, and the geological background has the maximum goodness of fit. Combined with the study on the physical geological body conditions in the region of interest, the contrast method is more suitable for the correction of systematic errors in stream sediment geochemical survey data on different map sheets in the Gouli Region and can be selected and applied in geochemical data processing under similar topographic and geomorphic conditions in Northwest China.

Groundwater pollution risk assessment is an effective tool for preventing and controlling groundwater pollution. The study on groundwater pollution risk assessment can serve as a basis for the management of groundwater contaminated sites. The present risk assessments often ignore the spatial variability of pollution within the site and the susceptibility of receptor. This paper proposes a new site groundwater pollution risk index system that can be used for pollution sites with a variety of features. The index system considers the spatial distribution of pollutant at the site and nearby receptors. Based on the four aspects of pollution load, vadose zone vulnerability, aquifer vulnerability, and receptor susceptibility, this paper conducted index screening and weight calculation using the analytical hierarchy process. A site groundwater pollution risk assessment index system was constructed, and the risk was divided into four levels: low, medium, higher, and high. Using the constructed risk index system, the spatial risk distribution of a hexavalent chromium site in Henan Province was studied. The results show that the site was at a medium risk level, with the highest risk at the chrome slag heaps and the southeastern of the buried chrome slag. The potential loss of surrounding receptors and the pollution load are the main causes of groundwater contamination risk at the site. Single parameter sensitivity analysis shows that the effective weights of each index are in line with the theoretical weights, indicating the rationality of the constructed site groundwater pollution risk assessment system, which can be applied to other sites with characteristic pollutants.

Geological reference material is a primary standard to ensure the accuracy of geological sample analysis results. After more than 40 years of development, China has developed and certified thousands of geological reference materials covering different media such as rock, ore, soil, sediment, organism, and water. China’s metrological management department divides the certified reference material into two classes according to the classification class, the first-class reference material (GBW) and the second-class reference material [GBW(E)]. According to their attributes and application fields, they are divided into 13 categories[6-7], and the geological reference materials belong to the seventh category [GBW07 and GBW(E)07]. It can be seen from the National Sharing Platform for Reference Materials (https://www.ncrm.org.cn) that by the end of the 13th Five-Year Plan, the total number of geological reference materials approved by the State Administration for Market Regulation is 1013, including 718 first-class certified reference materials, and the amount of first-class certified reference materials ranks first in the 13 categories (Fig.1). Geological materials are the most important and basic raw materials in the development of human society, with various types, complex components, and large differences in component content. It is because of the complexity of geological materials and the demand for reliable quantitative analysis that thousands of geological reference materials have been developed. Some reference materials developed by some industrial geological agencies are classified into other categories in classification management, such as isotope reference materials belonging to the fourth category, biological composition reference materials belonging to the tenth category, coal reference materials belonging to the eleventh category, these reference materials are widely used in related geological work, and in this paper they will be classified as geological reference materials. To systematically grasp the development status of geological reference materials in China, the first-class geological certified reference materials are comprehensively sorted, and are divided into six categories according to the type of matrix, property value and application scope: basic, ore, marine, environment, energy and special purpose (Table 1), and the development situation of each type, matrix characteristics and fixed value index respectively are summarized. On the basis of summarizing the results, on one hand, the main problems existing in the application of geological reference materials and the causes of these problems are analyzed. On the other hand, the detailed technical problems that may affect the uncertainty in the process of homogeneity, stability and characterization are discussed, and the views and suggestions are expounded. In this paper, the first-class geological certified reference materials are divided into the following six categories to summarize the development of each type: (1) 260 basic geological reference materials have been developed, the type of matrix including rock, soil and river sediments. The characteristic components of the certified value are generally 70 elements and compounds, which are mainly used as monitoring standards for sample analysis in basic geological surveys and research. (2) 272 ore geological reference materials have been developed, including precious metal ore, metal ore, single mineral, and non-metallic ore. The specific mineral types are shown in Table 1. There are generally 20 property values, which are the main technical indicators in mineral exploration. They are mainly used as a monitoring standard for geological exploration, mineral processing and smelting, comprehensive utilization, commodity inspection and trade amongst other fields. (3) 16 marine geological reference materials have been developed, including marine sediments and marine minerals. The specific samples include 10 marine sediment reference materials namely, 1 near sea, 1 Yellow Sea, 2 South China Sea, 1 East China Sea, 3 deep Pacific Ocean, 1 Antarctic Ocean and 1 Arctic Ocean. Six marine mineral reference materials are three polymetallic nodules and three ocean cobalt-enriched crusts. The characteristic composition of the certification value is the same as that of the basic geological reference material, but slightly less, generally 51-71 kinds. This is a necessary chemical composition measurement standard for marine sediment measurement and marine mineral resource survey and research. (4) 101 standard materials for environmental geology have been developed, including the available state of soil elements, the form of soil and sediment elements, the valence state of groundwater elements, the extractable state of soil elements, biological inorganic elements, organic pollutants in soil and sediment and other reference materials. The characteristic components of the matrix and certified values are the total amount of inorganic elements in biological samples, the available states, and forms of elements in soil and sediment, the valence states of elements in water and organochlorine pesticides, polychlorinated biphenyls, and polycyclic aromatic hydrocarbons in soil and sediment. This kind of reference material provides analytical quality monitoring standards for land quality geochemical surveys and evaluation, regional ecological geochemical evaluations, multi-objective geochemical surveys and detailed surveys of soil pollution. (5) 23 energy geological reference materials have been developed. The property values of oil-generating rock reference materials are organic carbon, pyrolysis hydrocarbon S2, pyrolysis peak temperature Tmax, and chloroform asphalt “A”. The property values of coal reference material are calorific value, ash, volatile matter, total sulfur, carbon, hydrogen, nitrogen, true relative density and phosphorus, chlorine, fluorine, and arsenic. The property values of the reference materials of highly evolved hydrocarbon source rock are pyrolysis hydrocarbon S2, pyrolysis peak temperature Tmax, and total organic carbon TOC. This is the monitoring standard for the exploration, evaluation and rational utilization of energy and mineral resources. (6) 129 reference materials for special purposes have been developed, including 20 synthetic reference materials for emission spectroscopy and 4 synthetic reference materials for X-ray fluorescence spectroscopy analysis. The property values are 28-29 inorganic chemical elements. There are 38 isotope reference materials, and the property values of those include isotope abundance and abundance ratio. There are 35 electron probe reference materials, and the property values are generally two principal components of their minerals. There are 15 reference materials for phase analysis, and the property values are the corresponding main phase. There are 5 soil limit water content reference materials, and the property values are 10mm liquid limit, plastic limit, and plastic index. There are 12 soil pH reference materials, and the property values are pH. It can be seen from the classification and summary that the geological reference material matrix in China is rich in types and quantities, which establishes an influential quality monitoring system for geological sample analysis, ensures the reliability and consistency of geological sample test data, and significantly improves the comparability and scientific value of relevant data. At present, there are still some problems in the application and development technology of a large number of geological reference materials. The problems are discussed and analyzed, hoping to draw attention to improving the value determination class of geological reference materials. In the aspect of application, the specific problems existing in different types of geological reference materials and their causes at the present stage are analyzed and development suggestions are proposed, according to the work needs of current mineral resources, international cooperation, marine strategy, ecological civilization and other fields. In the aspect of development technology, some detail technologies which may affect the value determination class in the process of homogeneity, stability and characterization are analyzed. In the aspect of development technology, some detail technologies which may affect the setting in the process of homogeneity, stability and value setting are analyzed. The test method of homogeneity and the evaluation method of stability uncertainty are discussed. Suggestions are made for the uncertainty evaluation method of unexamined elements for homogeneity test and control limit of relative extended uncertainty. 1. Three problems existing in the current application of geological reference materials are analyzed: (1) The quantity of some types of reference materials developed is small, the gradient distribution of characteristic values is insufficient, and the matrix type is simple. For example, the amount of marine geology, micro-area analysis, energy and mineral resource reference material development is small. The ore-forming elements of key metal ore reference materials are mainly low content, lacking rich ore grade or higher content grade. The matrix types of the samples of organic pollutant reference materials are only soil and sediment, and the property values are only organochlorine pesticides, polychlorinated biphenyls, polycyclic aromatic hydrocarbons and other compounds, and the matrix types and target compounds are few. The main reasons for these problems are difficulty in obtaining samples, little working demand, difficulty in ensuring the uniformity and stability of the sample preparation technology, large error of analysis technology unable to determine the value. (2) There are many components in the geological reference materials with mature development technology that have no certified values. The reasons of low element content and test interference are mainly analyzed. (3) At the current class of analytical technology, there is only one measurement method for several elements, and for some elements, with the widespread application of modern instrumental analysis technology, the optional measurement method is gradually becoming singular. 2. The detail technology of four aspects in the development of reference material is discussed: (1) Uniformity testing method. XRF is a widely used measurement method for the uniformity test of geological standard materials due to its high testing precision. However, due to its large sample size, XRF cannot meet the requirements of minimum sample size. Since the release and implementation of China National Technical Specification for Measurement “General and Statistical Principles for Characterization of Reference Materials” (JJF1343) in 2012, the uniformity of reference materials was tested by ICP-MS and ICP-OES under 0.1g weighing sample[24-30]. The measurement precision of these two methods is not as good overall as that of XRF, and the accuracy of individual elements is poor, which may cause the numerical value to be too large when calculating the uncertainty introduced by uniformity, thus affecting the reasonable evaluation of the uncertainty of property value. For this reason, some scholars[34-35] improved the XRF sample preparation device, studied the accuracy and precision of the method under 0.1g weighing sample, and verified the application effect for uniformity testing. However, only 10 major components in the reference materials of soil and stream sediments were tested under 0.1g weighing sample, while the reference materials of other matrix types and other trace elements, especially heavy elements, have not been studied and tested. Therefore, the feasibility of the XRF method with a sample size of 0.1g still needs to be verified. (2) Uncertainty calculation method for elements without uniformity test. The composition of geological materials is complex, and its reference substances generally have multiple attribute values, and the content of each component is greatly different, so it is usually difficult to test the uniformity of all attribute values. According to the provisions of JJF1646—2017, the characteristic of representative and less homogeneous should be selected for uniformity evaluation. The uncertainty of the untested elements can be evaluated according to the concentration and geochemical properties with reference to the uncertainty introduced by the tested elements. However, the exact calculation method was not specified. An evaluation method that considers both element properties, content and test methods (Table 2) is presented here. The specific calculation method is to multiply the relative uncertainty (Ur) of the uniformity of the detected element by the standard value μ of the undetected element and take it as the uncertainty component ubb of the undetected element. (3) Evaluation method of stability uncertainty. At present, trend analysis method is generally used to evaluate the stability uncertainty (us) of geological reference materials, and the calculation formula is us=s(b1)·t. It can be seen from the formula that the longer the stability monitoring time, the greater the stability uncertainty introduced. The stability uncertainty data of several reference materials were compared and determined to be the main contribution to the total uncertainty, which is inconsistent with the long-term observation of the stability of the geological reference materials. Therefore, this calculation method is not suitable to evaluate the uncertainty introduced into the stability of geological reference material. Meng et al.[42] suggested using the analysis of variance to calculate, and the comparative analysis showed that us was still the main contribution to the total uncertainty. Wang et al.[43] used range method to calculate us, but the application of this method in geological reference materials has yet to be verified. In conclusion, the reasonable evaluation of stability uncertainty of matrix reference materials with more test error sources needs to be studied further. (4) Control limits for relative extended uncertainty. The determination of the property value of geological reference materials usually has certain control requirements for relative extended uncertainty (Urel), but these control limits are rarely introduced in the public information of the reference material. It was not until the specification JJF1646 published in 2017 that Urel was required in principle. Urel is the embodiment of the quality of property value data. Urel control limits in Table 3 are proposed on the basis of the principle requirements of JJF1646—2017 by referring to the control limits in the development of existing reference materials and the analysis of different types of geological reference materials. In the process of development, the developer also needs to comprehensively consider the matrix condition, setting index, element content of the sample and formulate reasonable Urel control limits of uncertainty in combination with the current analysis technology class, to obtain accurate and reasonable property value and uncertainty.