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Background: The Mediterranean Sea is a region characterized by high seismic activity, with at least 200 tsunami events recorded from the fourth century to the present twenty-first century. Numerous studies have been conducted to understand past tsunami events, earthquake–tsunami generation, tsunami recurrence periods, tsunami vulnerability zones, and tsunami hazard mitigation strategies. Therefore, gaining insights into future trends and opportunities in Mediterranean Sea tsunami research is crucial for significantly contributing to all relevant aspects. This study aims to assess such trends and opportunities through a scientometric analysis of publications indexed by Web of Science from 2000 to 2023. Results: Based on a selection of 329 publications, including research articles, review articles, book chapters, and conference papers, published between 2000 and 2023, Italy has the highest number of publications and citations in this field. The number of publications has increased significantly, especially after the 2004 Indian Ocean, 2011 Tohoku, and 2018 Palu tsunamis. According to the keyword analysis, the terms "tsunami", "earthquake", "hazard", "wave", "Mediterranean", "coast", and "tectonic" were the most frequently used in these publications. Research themes consist of four classifications: motor themes, such as seismic hazard; specific but well-developed themes, like tsunamiite; emerging or disappearing themes, for example, climate change; and general or basic themes, such as equations and megaturbidite. The number of publications related to the motor theme classification continued to grow throughout 2000–2023. Topics from 2011–2023 are more complex compared to 2000–2010, characterized by the emergence of new keywords such as evacuation planning, risk reduction, risk mitigation, building vulnerability, coastal vulnerability, climate change, probabilistic tsunami hazard assessment (PTVA-3 and PTVA-4). However, topics that were popular in the 2000–2010 period (e.g., paleotsunami deposits, earthquake, and tsunami propagation analysis) also increased in 2011–2023. Conclusions: Research topics with high centrality and density such as seismic hazard will continue to develop and prospect. The cluster network of this topic includes seismoturbidites, sedimentary features, tsunami modeling, active faults, catalog, and historical earthquakes. [ABSTRACT FROM AUTHOR]

Human-induced earthquakes are an issue of foremost significance affecting multiple industries such as geothermal, oil and gas, water, mining, and waste disposal. Current research addresses global monitoring of induced earthquakes, case histories, improving monitoring techniques, understanding the physical mechanisms involved, forecasting, mitigating risk, predicting the magnitude of the largest possible earthquake, and assessing impacts and stakeholder opinion. This Guest Editor Collection presents over 20 research papers summarizing the current state of knowledge throughout all aspects of the subject, and comprises an excellent resource for stakeholders. [ABSTRACT FROM AUTHOR]

Interpretation plays a central role in using scientific models to explain natural phenomena: Meaning must be bestowed upon a model in terms of what it is and what it represents to be used for model explanations. However, it remains unclear how capacious and complex interpretation in models can be, particularly when conducted by the same group of scientists in the context of one explanatory project. This paper sheds light upon this question by examining modelling and explanatory practices related to the Olami-Feder-Christensen model of earthquakes. This case study shows that various interpretations are intricately connected in the overall meaning of a model used for model explanations. This leads to a manifold picture of interpretation, according to which scientific models are construed as networks of interconnected meanings. As scientists ponder and integrate these various interpretations, guided by locally attended epistemic interests, they achieve model explanations with layers of content, both in their explanantia and explananda. [ABSTRACT FROM AUTHOR]

According to B.L. Berry's 'harmonic model,' any natural or social process is a superposition of several cosmic rhythms. The author assumes that stability of these rhythms allows prediction of earth phenomena over an unlimited time. We show that the statistical criteria supposedly substantiating the harmonic model were applied incorrectly. The initial data for the analysis were biased and selected incompetently; the adequacy of the methods used was not verified. Predictions of natural catastrophes (earthquakes, weather anomalies, etc.) and various social events according to Berry's model are unsatisfactory. Statistics do not confirm that these predictions are at least slightly better than random guessing. Berry's model is unacceptable; it is untenable both in detail and in general. [ABSTRACT FROM AUTHOR]

Earthquakes endanger lives and properties and trigger widespread online public opinion. If the government fails to implement emergency measures quickly, the risks associated with this online public opinion may escalate and present significant challenges in managing it. To solve this issue, this paper investigates the M5.7 earthquake in Yibin, China, as a case study, drawing data from China's Sina Weibo. It also develops an evolutionary model of earthquake online public opinion using the life cycle theory of public opinion dissemination, public opinion crisis management theory, and system dynamics methods. This study chooses a system dynamic model because it can capture overall trends and feedback cycles. This approach provides a comprehensive view of the evolution of the whole system's behavior and public opinion during the crisis. This model analyzes the evolution of the online public opinion of the earthquake from the perspective of the earthquake, netizens (social media users), media, and government. This study explores the differences between online public opinion by adjusting the size of different variables in the model. This provides an entry point for better control of the development and communication of earthquake online public opinion. The findings indicate that, following the earthquake, the media exerted the most significant influence on public opinion, mainly through media participation, diffusion, and impact, demonstrating a significantly positive correlation with the magnitude of public opinion. Moreover, the simulation revealed that the government is leading in preventing and controlling online public opinion. This study presents the following innovations: (1) It builds a comprehensive online public opinion model for earthquakes, which provides insights for studying online public opinion regarding other sudden natural disasters. (2) It employs system dynamics to simulate earthquake online public opinion, providing countermeasures and recommendations for the government to manage and regulate this discourse effectively. [ABSTRACT FROM AUTHOR]

Earthquakes present formidable challenges to structural stability, driving the need for ongoing advancements in construction methodologies. This review highlights the crucial role of Geopolymer Concrete (GPC) in enhancing earthquake resistance and addresses the need for innovative solutions. The review begins with an overview of the importance of earthquake-resistant construction practices, emphasizing that the next generation of GPC can increase flexural strength by up to 30% compared to conventional GPC concrete when incorporating nanomaterials such as nano-Al2O3, nano clays, and nano-SiO2. A detailed survey of current earthquake-resistant strategies reveals that while traditional concrete is susceptible to chloride attacks, GPC demonstrates a 37% lower vulnerability and significantly improved durability under harsh environmental conditions. The paper presents real-world case studies where GPC has been successfully implemented in seismic applications, illustrating effective enhancements in structural resilience metrics. The review then explores various emerging strategies for earthquake-resistant GPC, elucidating their unique features and advantages for seismic applications. Real-world case studies and examples illustrate the practical success and effectiveness of these next-generation strategies in improving structural resilience. The paper also outlines performance evaluation criteria for seismic structures, showing how these new approaches offer notable improvements over traditional methods. Challenges associated with implementing these advanced strategies are discussed, along with innovative solutions and recent advancements in the field. A comparative analysis of traditional and next-generation approaches highlights their respective benefits and potential drawbacks. The review concludes with an outline of future research directions and prospects for further enhancing GPC structures against seismic forces. This review consolidates key findings and underscores the transformative potential of next-generation strategies in earthquake-resistant construction. [ABSTRACT FROM AUTHOR]

The 2009 and 2012 earthquakes in Italy occurred in a close-knit region and time horizon but differed substantially on both the initial shock to the stock and the subsequent flow of resources. This paper considers the short run impact on the dynamic response of labor market outcomes. Both earthquakes lowered employment and labor force participation by more than 0.5%. With its negative effect on the resources available, the 2009 shock led to a drop in real wages of 1.3% and a sharp—but short-lived—widening of the wage gap generated by the skill premium. The 2012 earthquake, which led firms to upgrade their technology, increased wages by 2.2% and led to a more balanced—but persistent—widening of the wage gap. The predictions of a model developed in this paper are consistent with these results. [ABSTRACT FROM AUTHOR]

In this paper, we performed microseismicity detection and location using the deep learning method and obtained a high-precision earthquake catalog in the Changning gas field, which is one of the largest shale gas production demonstration areas in China. We found that the spatial and temporal characteristics of seismicity in the region are indicative of its correlation with industrial operations. The distribution of earthquakes at depth reflected variations in reservoir depth and provided valuable constraints on it. The horizontal layered distribution of earthquakes at depth is due to the formation of fracture surfaces from interconnected fractures near the reservoir during hydraulic fracturing (HF) operations, which clearly demonstrates how HF operations impact seismicity. We suggested that the horizontally layered distribution was driven by two fundamental mechanisms: reactivation of pre-existing faults during HF and injection of high-pressure fluids into the reservoir, leading to fracture creation. Several ML ≥4 earthquakes, which did not occur on well-defined seismogenic faults, may have been triggered by pore elastic coupling resulting from regional stress accumulation and fluid injection. Significantly, the ML 4.9 seismic sequence occurring at the basement indicates that fracking has reactivated and promoted pre-existing faults, highlighting the need for further investigation into potential seismic hazards in the region. [ABSTRACT FROM AUTHOR]

The preface for the article collection "10 years after the 2011 Tohoku earthquake: a milestone of solid earth science" highlights the scientific discoveries made since the earthquake, thanks to near-field observations and existing knowledge about the northeastern Japan arc. The earthquake revealed dynamic frictional behaviors of the subduction interface and provided insights into subduction zone dynamics. The collection of research on the Tohoku earthquake is expected to benefit the understanding of subduction earthquakes worldwide. The preface also mentions various research papers included in the collection, covering topics such as coseismic stress drop, afterslip, seafloor observations, slow earthquake activity, tsunami deposits, paleoseismology, and numerical modeling of the earthquake cycle. Ongoing research on postseismic deformation and historical research on earthquake occurrence are also discussed. The authors express their appreciation to the reviewers and the editorial board for their contributions to the special issue. [Extracted from the article]

In the last thirty years, Seismic Structural Health Monitoring (S SP 2 sp HM) has received a growing interest from both researchers and professionals, and an increasingly high number of seismic monitoring systems are currently installed in various countries. Therefore, the paper B Liao et al. b shows that medium-quality accelerometers (MEMS-based instruments) can provide feasible solutions for cost-effective city-scale deployment and performances that are superior to those of sensor networks with high-quality accelerometers. Vibration-based damage identification techniques are thus an important decision support tool that is being investigated by several research groups using both data-driven and model-based approaches. [Extracted from the article]

In Geophysics, topographic factors are observations that can be directly measured, but they are often ignored to simplify the model. Studying the coseismic deformation caused by earthquakes helps accurately determine the epicenter's parameterization. It provides a reference for the reasonable layout of coseismic observation stations and GNSS observation stations. After the Mw7.8 earthquake in Nepal in 2015, GCMT, USGS, GFZ, CPPT, and other institutions released their epicenter parameter. However, according to their parameters, the coseismic displacements simulated by the spectral-element method are quite different from the GNSS observations. Firstly, this paper inverts the geometric parameters of the seismogenic fault with Nepal's coseismic GNSS displacement. The spectral-element method determines the source's location and depth under the heterogeneous terrain and outputs the source parameters. Among the results of many studies, the surface source is more consistent with the generation mechanism of large earthquakes. Secondly, this paper calculates the fault slip distribution of this earthquake using SDM (Steepest Descent Method) based on GNSS and InSAR data, which is divided into 1500 subfaults, and the moment tensor of each subfault is calculated. This paper investigates the distribution characteristics of the coseismic deformation field of the 2015 Mw 7.8 earthquake in Nepal under three different models. The results show that the influence of topographic factors is ~ 20%, and the influence of heterogeneous factors is ~ 10%. This paper concludes that the influence of topographic factors is much more significant than that of heterogeneous factors, and the influence of both should be addressed in coseismic deformation calculations. [ABSTRACT FROM AUTHOR]

Strong earthquake geological hazards cause significant social and economic losses. The assessment of post-earthquake socioeconomic development levels is one of the important bases from which to measure the recovery capacity of hazard areas. However, the long-term impact of geological hazards is rarely considered in the assessment of the socioeconomic development level of a mountainous earthquake-stricken area. The purpose of this paper is to study the complex relationship between earthquake geological hazard effects and socioeconomic development in the long-term post-earthquake development and reconstruction of mountainous extremely earthquake-stricken areas, to provide a reference for the study area to achieve regional sustainable development goals and high-quality development. On this basis, using the economic, social, ecological environment and other relevant data from 2008 to 2016, and using unsupervised machine learning algorithms, a socioeconomic development level evaluation model based on spectral clustering was established, and the effects of different kernel function scale parameters on the model were analyzed. The optimal parameters were determined, and the spatiotemporal analysis of the socioeconomic development level of the study area was carried out. The research results show that the performance of the evaluation model is optimal when the output category is 4 and the scale parameter is 0.26, and the scale parameter of the kernel function is an important indicator that affects the accuracy of the model. From 2008 to 2016, the socioeconomic development level of Qingchuan has always been at a very low level, Wenchuan and Beichuan have always been at a low level, Shifang and Mianzhu have always been at a high level, and Pengzhou and Dujiangyan have always been at a very high level. The socioeconomic development level of Anxian, Maoxian and Pingwu fluctuates greatly over time. Another interesting finding is that the socioeconomic development level of the mountainous earthquake-stricken area has a strong correlation with its own industrial structure and landslide hazard effects. The work done in this paper is of great significance for understanding the temporal and spatial effects of hazards and understanding the complexities of regional disaster systems. [ABSTRACT FROM AUTHOR]

The analysis of collaborative contribution networks and hot spots in earthquake research from a global perspective will reveal some rules and trends in this field that will provide references and macroguidance for scientific researchers in the field. With the help of data analysis software Excel and visualization software VOSviewer, this study mainly uses two methods of bibliometric and social network analysis to analyze 66,296 papers on the subject of "earthquake" collecting in Web of Science in 2009–2018 from multiple perspectives. In the past 10 years, scientific research output in the earthquake field has steadily increased year by year with an evident cross subject. The contribution of co-publishing is much higher than that of single publishing, and it has a higher number of citations and displays. Half of the 50 keywords with the highest frequency of co-occurrence are the continuation of hot spots in 1900–2010. The evolution of hot spots shows that in the average publishing year of 2013.5–2015.0, hot spots have changed from old to new, but few new hot spots have appeared in the past 2 years. [ABSTRACT FROM AUTHOR]

In order to study the effect of the velocity pulse on the dynamic response of the train-bridge system of the high-speed railway simple supported beam bridge, the velocity pulse is simulated by the trigonometric function method and superimposed with the far-field earthquake without pulse to synthesize the pulse with different pulse types, pulse periods and pulse peaks. A 10 × 32m typical high-speed railway simple supported beam bridge is considered an case illustrating study. Then, the dynamic response of train-track-bridge coupling system is calculated by train-track-bridge seismic analysis software TTBSAS. Afterwards, the influence of pulse near-field earthquakes parameters and vertical components on dynamic response of train-bridge system and the safety of the train on the bridge are discussed in detail.The new derailment evaluation index is adopted to evaluate driving safety under earthquakes. The train safety control of simply supported beam bridge under the action of near-field earthquake is studied. The results show that the impact of pulse ground motion on the dynamic response of the train-track-bridge coupling system is significantly higher than that of no-pulse ground motion, especially the impact on the bridge and rail subsystem is more significant than that of train subsystem. Under the excitation of ground motion intensity of 0.05g ∼ 0.15g, the safe speed threshold of pulse near-field ground motion is smaller than that of far-field ground motion. When the ground motion intensity is 0.20g ∼ 0.30g, the safe speed threshold of pulse near-field ground motion and far field ground motion is 200km/h. So, the pulse near-field earthquake poses a greater threat to the safety of the train on the bridge than the far-field earthquake. Therefore, the influence of pulse near-field earthquakes should be considered in the seismic design. The research results of this paper can provide theoretitcal support for the design of a high-speed railway bridge in the near-field area. [ABSTRACT FROM AUTHOR]

Abstract—This paper analyzes the use of the automated aftershock hazards assessment system (AFCAST) through the example of a series of aftershocks of the Mw 7.8 earthquake in Turkey of February 6, 2023 (the Pazarcik earthquake). The paper presents automated estimates of the aftershock activity area, the magnitude of the strongest aftershock, and the duration of the hazardous period, yielded using data on the main shock and on the first aftershocks. [ABSTRACT FROM AUTHOR]

The hospital system is one of the most critical systems in the city and plays an irreplaceable role in the whole process of earthquake disasters. This paper presents a method that considers the medical supply–demand relationship to quantify the functionality and functional loss of a hospital system under earthquake conditions, which is different from the current quantitative method that only considers internal factors of the hospital system. This method provides a "finest granularity" method for the division of quantitative evaluation units of hospital system functionality based on GIS overlay. Secondly, the functionality of the hospital system considering the medical supply–demand relationship and the quantitative metric, substitution capacity of medical resources (SCMR), is constructed. Then, we propose a quantification method of SCMR by combining the spatial and network analysis methods. Finally, a hospital system in eastern China is considered as an illustrative example. The impact of changes in the medical supply and demand at different times of the day on the hospital system functionality is analyzed. The results show that the medical supply and demand can impact hospital system functionality. The loss of medical supply causes a decline of hospital system functionality, while changes in the spatial aggregation of medical demand positively affect the loss of hospital system functionality. This paper can use the proposed method to quantify the hospital system functionality and reflect the balance of the medical supply–demand relationship before and after the earthquake. It can help decision-maker develop scientific post-earthquake emergency plans and enhance hospital system resilience. [ABSTRACT FROM AUTHOR]

Active seismicity, which began since late 2020 under the Noto Peninsula, Japan, led to the M7.6 earthquake on the 1st January 2024. This paper analyzes the M5.9 pre-event that occurred 13 s before the M7.6 mainshock. Near-field ground motion records clearly distinguish this pre-event from the ground shaking of the mainshock. We then use six near-field ground motions over a 10-s period to obtain first the focal mechanism and then dynamic rupture models by fixing the hypocenter location. We obtain a steep dip angle of 67°, whereas the dip of the M7.6 mainshock is 33° after Japan Metrological Agency catalog. We propose a simplified inversion process that dynamic rupture models are built by varying the location of the target circular patch, the stress level and the fault dipping directions. The preferred model has an up-dip rupture directivity (rake direction) on the south–east dipping fault, i.e. propagating away from the hypocenter of the M7.6 mainshock, and the two events are not aligned on the same planar fault. Uplift of about 20 cm and more is expected on the north coast of the Noto Peninsula in the case of the stress drop of 6 MPa or less. We also analyze another M5.5 pre-event 4 min earlier, with a slightly deeper focal depth and a gentle dip angle of 36°. This earthquake has also a rupture directivity in the up-dip direction. This infers that there should have been a preparation process of the M7.6 mainshock behind these pre-events and multiple fault segmentations around the hypocenter zone might have played a role. [ABSTRACT FROM AUTHOR]

The Irpinia Fault, also known as the Monte Marzano Fault System, located in the Southern Apennines (Italy), is one of the most seismically active structures in the Mediterranean. It is the source of the 1980, Ms 6.9, multi-segment rupture earthquake that caused significant damage and nearly 3,000 casualties. Paleoseismological surveys indicate that this structure has generated at least four Mw ~ 7 surface-rupturing earthquakes in the past 2 ka. This paper presents a comprehensive, high-resolution geophysical investigation focused on the southernmost fault segment of the Monte Marzano Fault System, i.e., the Pantano-Ripa Rossa Fault, outcropping within the Pantano di San Gregorio Magno intramontane basin. The project, named TEst Site IRpinia fAult (TESIRA), was supported by the University of Napoli Federico II to study the near-surface structure of this intra-basin fault splay that repeatedly ruptured co-seismically in the past thousands of years. Our imaging approach included 2D and 3D electrical and seismic surveys, gravimetry, 3D FullWaver electrical tomography, drone-borne GPR and magnetic surveys, and CO2 soil flux assessment across the surface rupture. This multidisciplinary investigation improved our understanding of the basin shallow structure, providing an image of a rather complex subsurface fault and basin geometry. Seismic data suggest that fault activity at the Pantano segment of MMFS is characterized by a near-surface cumulative displacement greater than previous estimations, calling into question earlier assumptions about the timing of its activation. Despite some challenges with our drone-mounted survey equipment, the integrated dataset provides a comprehensive and reliable image of the subsurface structure. This work demonstrates the utility of developing an integrated approach at high-resolution geophysical imaging and interpretation of fault zones with weak morphological expressions. [ABSTRACT FROM AUTHOR]

Given the uncertainty in earthquake forecasting, seismic hazard analysis has been considered to be the better method to estimate site-specific response spectra in seismic design. This research addresses a seismic hazard study for the Sarcheshmeh Copper Site in the Kerman Province, in southeast Iran. The first part of this paper includes an evaluation of seismotectonic and seismicity conditions throughout the study area. The second part addresses the seismic hazard analysis procedure followed by the determination of design ground motion parameters which is finally expressed in terms of peak ground acceleration in deterministic and probabilistic schemes. The peak ground acceleration (PGA) was obtained for the 75-, 475-, and 2475-year return period spectrum. (Kijko and Sellevoll's in Bull Seismol Soc Am 79(3):645 654, 1989) method was used for the evaluation of seismicity parameters, and the SEISRISK III computer program was used to conduct the probabilistic seismic hazard analysis. Finally, the third part is devoted to the development of the earthquake design spectrum obtained by dynamic ground response analysis. Site response analysis program, EERA (Equivalent-linear Earthquake site Response Analysis), which implements an equivalent linear approach, was used for one-dimensional ground response analyses. The subsurface conditions including the geometry of the soil layers and their dynamic properties were extracted from the geotechnical investigations. Based on the results, the PGA values for the 75-, 475-, and 2475-year return period spectrum are 0.087, 0.302, and 0.425, respectively. This paper can provide guidance on conducting seismic hazard analyses at other sites. Also, the results could be used for earthquake-resistant design of civil engineering infrastructures of the studied area. [ABSTRACT FROM AUTHOR]

It is proposed in this paper to use the focal characteristics of small seismic events, in particular, the scaled energy and the rupture propagation velocity, as indicators of possible dynamic movements along a fault. The two sites selected for analysis underwent microseismic events induced by mining operations. The first site, the Korobkovskoe iron ore deposit of the Kursk Magnetic Anomaly, is located in the aseismic region. The second site, the apatite–nepheline deposit of the Khibiny massif, is characterized by relatively intensive natural and human-triggered seismicity. Based on the results of the analysis, the values of the scaled seismic energy and the rupture propagation velocity are drastically different at the deposits under consideration. At the apatite–nepheline ore deposit, the parameter values are close to the range of values characteristic for "normal" earthquakes. At the KMA deposit, the obtained anomalously low values of the scaled energy and the rupture propagation velocity correspond to "slow" earthquakes. The results obtained are indicative of the prospects for using the selected parameters as indicators of possible large dynamic events at the studied site of the fault zone. [ABSTRACT FROM AUTHOR]

The characterization of the cyclic resistance of soils is more important for the prediction of the liquefaction potential and the safety of the buildings. Thus, various cyclic resistance curves had been proposed in the literature and improved regularly. The hyperbolic boundary function (HBF) model based on standard penetration test (SPT) data was developed from a database of 669 sets, which includes 302 sets of Chi-Chi earthquake data and 367 sets of data collected by Youd and his colleagues. This model is based on the Seed and Idris hypothesis, which states that the peak shear stress induced at a given depth is always less than that deduced from the simplified procedure of Seed and Idriss. Filali and Sbartai, based on a suite of equivalent linear site response analyses, showed that the peak shear stress induced by an earthquake can in many cases be greater than the simplified peak shear stress; it means that the rd factor became greater than 1. In this case, the assumption on which is based the simplified procedure is not always verified. For this reason, Filali and Sbartai proposed an earthquake corrector factor (RC) in the range where the shear stress reduction factor (rd) is greater than 1 to adjust the deformable and rigid body. In this paper, we will perform a probabilistic analysis to evaluate the liquefaction potential using a database based on standard penetration test collected after the Chi-Chi Taiwan earthquake with a cyclic stress ratio computed using the proposed corrector factor. This paper presents an adjusted model of the Bayesian mapping function that relates deterministic factor of safety to probability of liquefaction (PL) using the corrected version of the simplified method. In this study, probability boundary curves derived from a Bayesian mapping function are presented based on the original and the corrected version of the simplified method in order to show, in each case, the position of the deterministic boundary curve defined by the hyperbolic function (HBF) model with respect to the probability of liquefaction. The paper also presents an updated form of the hyperbolic function (HBF) model based on the true position of the probabilistic boundary curve according to the corrected version of the simplified method. [ABSTRACT FROM AUTHOR]

Background: The landslide inventory of the western flank of Mount Oku, Cameroon, includes spreads or complex landslides, indicating sudden soil weakening, possibly due to seismic activity or heavy rainfall causing groundwater rise. These landslides were likely triggered between 2009 and 2018 based on the dates of the aerial imagery. Identifying triggers for past landslides remains a major unresolved issue in landslide science. However, understanding these triggers is crucial for accurately assessing future landslide hazards. Methodology: In this paper, we investigate the possibility of earthquakes to precondition landslide development or reactivation during climatic events. By assuming a magnitude 5.2 earthquake, an epicenter of 10 km from this area, and different wetness conditions, the factor of safety (FS) and Newmark displacement (ND) models were calculated for shallow and deep-seated landslides with sliding depths of 3 and 7.5 m. Afterward, the relationship between FS, assumed ND, and observed landslides was analyzed in a cluster analysis, to derive patterns of climatically and seismically triggered landslides. Results: The comparison of FS maps and FS values of the observed landslides revealed that especially for landslides at 7.5 m depth, most sites that are stable during dry conditions become instable under saturated conditions, indicating a climatic trigger. At 3 m depth, however, some landslide sites that are still marginally stable under saturated conditions, display relatively high ND values for the investigated hypothetical earthquake, indicating a possible seismic influence. In the cluster analysis, we clustered the observed landslides according to their distances to rivers and topographic ridges and obtained three clusters. Landslides from cluster 3 with 31% of the landslides display medium to high ND for the assumed earthquake, and were found near ridges and farther away from rivers, suggesting seismic triggering. Cluster 2, with 12% of landslides closer to rivers, suggested climatic origins. Thus, while climate is a critical landslide contributing factor, seismic events may also contribute, either by predisposing to landslides or by reactivating them alongside climatic factors. These results enable the establishment of more precise and effective landslide mitigating measures considering mostly rainfall but also earthquakes as possible triggers. [ABSTRACT FROM AUTHOR]

In this paper, we present a description of a database of earthquake focal mechanisms, which is compiled from the data of international seismological agencies and literature sources for the East Arctic region. It consists of 595 focal mechanism solutions for 273 seismic events with M = 2.1–7.6, which occurred in 1927–2022. Information about the source depth, the scalar seismic moment, and the moment magnitude are also presented there for many events. In addition to the focal parameters, their quality assessments are available, which facilitates a comparison of different solutions in many cases. For user convenience, the database has a graphical interface that permits searching by various attributes (coordinates, time, magnitude, and depth). In terms of volume of the collected information, our database significantly exceeds all the analogues available at the present time. It can be used to perform a seismotectonic analysis, to estimate the stress–strain state of the lithosphere, and to assess seismic hazard for the entire East Arctic region or its separate areas. Implementation of the compiled database for comparison of different solutions of earthquake focal mechanisms and their seismotectonic analysis is illustrated in the paper on the example of seismic events occurred in the Olenek Bay of the Laptev Sea and adjacent territories. We suggest adding new information to the database every five years in future. [ABSTRACT FROM AUTHOR]

This paper is focused on study of the geomagnetic field variation response caused by a series of earthquakes with magnitudes of Mw = 7.5–7.8 in Turkey on February 6, 2023. The initial data include high-precision observations of the geomagnetic field with a one-second sampling rate recorded at magnetic observatories in Russia and neighboring countries from middle to high latitudes. The paper analyzes the morphology of the geomagnetic signal, its amplitude-frequency characteristics, pulses in the rate of change and delays of the geomagnetic field response to earthquakes with magnitudes Mw = 7–8 depending on the distance to the source. The results suggest that the geomagnetic effect is detected best in the rate of change recordings, reaching anomalous amplitudes of 10 nT/s. The signal delay ranges from 221 to 592 s depending on the magnetic field component and the distance to the epicenter, which is in the range from 765 to 2650 km for the selected observatories. [ABSTRACT FROM AUTHOR]

In this paper, a scalable end-to-end tree boosting system called XGBoost has been applied for predicting the magnitude of an earthquake from the early part of earthquake waveform data. This model uses the features extracted from the early P wave phase of the records as an input. The model's effectiveness has been verified by using data on earthquakes occurring in the Eurasian plate of Japan Islands from 1996 to 2021. Feature engineering has given 29 new features identified from the early P wave phase of the record, which show a high correlation with the magnitude of an earthquake. The comparison of predicted and actual magnitude shows that a trained XGboost model, which uses a single input record for magnitude prediction, gives an average prediction error of 0.004 ± 0.57 for earthquakes in the test dataset. In contrast, the average prediction error of –1.1 ± 0.80 and –0.65 ± 0.69 has been obtained for the magnitude estimated from conventional τc and Pd methods using the same test dataset. It is further seen that the average predicted magnitude of a single earthquake of magnitude 4.5 and 6.1 (MJMA) obtained by using multiple nearfield records using XGBoost model is 4.58 ± 0.33 and 6.32 ± 0.29, which is close to the actual magnitude of the earthquake. The results presented in this paper clearly show that the structured data can be effectively used by complex machine learning or deep learning models to predict earthquake magnitude from single or multiple records. [ABSTRACT FROM AUTHOR]

This paper investigates the earthquake response of the Kömürhan cable-stayed bridge with a single pylon and steel deck, which was exposed to the Elazığ-Sivrice earthquake (Mw = 6.8) on January 24, 2020, while it was under construction. The distance from the epicenter to the bridge is approximately 23 km. 82% of the Kömürhan bridge deck was completed during the Elazığ-Sivrice earthquake in 2020. The spectral accelerations of the Elazığ-Sivrice earthquake are approximately 2.5 times greater than those of the design earthquake (72-year) considered during the construction stage. This paper first presents the characteristics of the Kömürhan cable-stayed bridge and the Elazığ-Sivrice earthquake (Mw = 6.8). Subsequently, a 3D numerical finite model of the Kömürhan cable-stayed bridge under construction is created. Modal and seismic responses of the deck, pylon and cables of the bridge under construction are compared for the load combinations including the design (72-year) and the Elazığ-Sivrice earthquakes. The result shows that under the 2020 Elazığ-Sivrice earthquake, the maximum vertical displacements, axial forces, and bending moments of the deck, as well as the cable forces, are three times greater than the design values (72-year). Nevertheless, despite the significant increase in the structural response, no visual damage was observed on the structural elements. This highlights the conservative design of the Kömürhan cable-stayed bridge. [ABSTRACT FROM AUTHOR]

Purpose: Considering the sudden change of the structure shape of a double-tower structure with a large podium (DTS), the mechanical properties of the structure under earthquake are extremely complex. Therefore, it is very important to evaluate the seismic fragility of new structures such as the DTS under different control schemes. This paper uses the seismic fragility analysis method based on IDA to study the seismic performance of the DTS. By comparing and analyzing the control effects of different control schemes, the advantages of composite passive control schemes are highlighted, which provides a theoretical basis for pre-earthquake disaster prevention and post-earthquake damage assessment of the DTS. Methods: With the aim of minimizing the mean–variance of the total vibration energy of the structure, the optimal control parameters of the energy dissipation damper are obtained by combining theoretical analysis with finite element simulation. Then the optimal arrangement scheme of the energy dissipation damper is determined by arrangement and combination. Considering that the previous structural performance level division methods cannot accurately reflect the results of the seismic fragility analysis of the DTS, the performance grade and damage grade of the structure were divided into five limit states and six damage degrees for the first time in this paper, and on this basis, the seismic fragility analysis of the DTS under two different control schemes was carried out based on IDA. Results: The response curves of each substructure of the equivalent single-DOF model are consistent with those of the multi-degree-of-freedom layer shear model (multi-DOF model), which indicates the validity and rationality of the equivalent single-DOF model are verified. Conclusion: The research shows that the equivalent single-DOF model of the DTS avoids a large number of iterative calculations, improves the calculation efficiency, retains the accuracy of the multi-DOF model, and has good applicability and rationality. In addition, the finite element simulation results show that the failure of the DTS under the two control schemes is caused by the failure of the isolation bearing. Compared with the LIC scheme, the CPC scheme improves the structure's seismic performance as a whole. [ABSTRACT FROM AUTHOR]

A natural disaster like an earthquake has the capability of damaging critical infrastructure systems, and valuable assets, limiting products or services movements, and in extreme conditions may cause injuries and even mortalities. The unavailability of a workforce as a response to an earthquake can directly affect the regional sector's productivity, as most business operations are labor dependent. In addition, the inherent interdependency of regional economic sectors can further delay the recovery process, This paper presents the dynamic inoperability input–output (DIIM) model and sector resilience to formulate a recovery analysis model by incorporating both the deterministic and stochastic modeling for workforce-interdependent sectors in the aftermath of an earthquake. The developed model is capable of evaluating the social and economic losses caused by workforce disruption. Moreover, a risk-based framework developed for the guidance of policymakers is to manage and control the adverse effects of the earthquake on the disrupted region. This paper identifies and prioritizes critical industry sectors based on two metrics i.e., inoperability and economic loss. Inoperability levels describe the percentage variation between the maximum production of the sector to the reduced production level, while economic loss is the quantified monetary value associated with the reduced level of sector output. The main contribution of this work focuses on the modeling of uncertainty caused by new disruption to the interconnected sectors within a recovery horizon of the initial outbreak of the disaster using a dynamic model for the disrupted region. This model is developed and applied to the regional sectors of Pakistan for an earthquake disaster but can be generalized to other regions and other disaster scenarios as well. Finally, the purpose of presenting different earthquake intensity scenarios is to validate the effective use of risk and uncertainty analysis in modeling the inoperability and economic loss behaviors because of time-varying perturbations and their related ripple effects on interdependent economic sectors. [ABSTRACT FROM AUTHOR]

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Recent geodetic measurements have detected recurrent slow slip events (SSEs) in many subduction zones. Numerical simulations suggest that the recurrence intervals and magnitudes of such SSEs decrease in the later stage of the interseismic period. Therefore, activities of SSEs and their temporal variations in recurrence intervals and magnitudes provide important clues for evaluating future large earthquakes. However, our knowledge of recurrent SSEs before the establishment of dense observation networks is limited. Here, we report a possible SSE in 1973 beneath the Kii peninsula along the Nankai subduction zone, southwest Japan, where magnitude 8 class earthquakes such as the 1944 Tonankai and 1946 Nankai earthquakes repeatedly occur. The possible SSE was detected by a horizontal pendulum tiltmeter installed in 1947 at the Kishu observatory. We recovered and converted the original tilt records from 1969 to 1974 drawn on bromide (light sensitive) papers to digital tilt records. In late-November 1973, there was a slow transient signal down to the northeast of about 1.4 μrad, lasting about 1–3 days. Assuming this crustal deformation was due to an SSE, we searched for a possible fault model by adopting the already-known SSE models occurring from 1996 to 2012 as template models. Among the 42 template fault models, five models were able to qualitatively explain the direction of the observed tilt change. The centroids of these fault models were located about 30–60 km to the west of the observatory. In the source region, two magnitude 5 class earthquakes occurred before the initiation of the transient signal, and thus may be related to the occurrence of the possible SSE. In contrast, the magnitude of the calculated tilt change was about 1–2 order smaller than that of the observed tilt change. This discrepancy could be partly explained by a slip amount larger than that in the template models, which suggests that the possible SSE in 1973 was larger than those detected by recent observations. Further investigation of historical data on crustal deformation will reveal more about the temporal change in the recurrence intervals and magnitudes of SSEs during earthquake cycles of large earthquakes. [ABSTRACT FROM AUTHOR]

Background: Rock slope instability is a complex geotechnical issue that is affected by site-specific rock properties, geological structures, groundwater, and earthquake load conditions. Numerous studies acknowledge these aleatory uncertainties in slope stability assessment; however, understanding the rock behaviour could still be improved. Therefore, this paper aims to summarise the probability methods applied in rock slope stability analysis in mining and civil engineering and develop new probabilistic design and assessment methodologies for four methods, namely empirical/rock mass classifications techniques, kinematic analysis, limit equilibrium (LE), and numerical methods and introduces how to integrate all methods to determine the total probability of failure. The case studies have been conducted based on slopes from Indonesia, a seismically active country, utilising the proposed design methods. Results: Regarding the probabilistic empirical/rock mass classification (RMC) technique, this study has identified that seven of the ten most involved input parameters in RMC naturally exhibit aleatory uncertainty. Thus, the optimal way to present the output probability of RMC is as a confidence interval (CI) or total and conditional probability associated with each rock mass class. In probabilistic kinematic analysis, this study presents a systematic method to compute the probabilities of different types of failure alongside the total probability of occurrence (PtK). The probability of failure (PoF) for jointed generalized Hoek-Brown (GHB) numerical modelling was lower than that obtained through the probabilistic LE approach for a similar slope. However, the PoF of jointed GHB is higher than the LE approach when loaded with 0.1 and 0.15 earthquake coefficients. Conclusions: The variation of PoF across different failure criteria determines how epistemic uncertainty is apparent in the modelling process, while the aleatory uncertainty arises from input parameters. Furthermore, this study introduces the total probability of failure equation as a combination of kinematic and kinetic probabilities (limit equilibrium and numerical modelling). [ABSTRACT FROM AUTHOR]

After the occurrences of large-scale earthquakes, secondary damage (e.g., fire following earthquake) can result in tremendous losses of life, properties, and buildings. To reduce these disaster risks, fire following earthquake assessment methods composed of ignition and fire-burned rate estimation models have been utilized. However, previous methods required for large amounts of building and GIS information, and complex modeling and analysis processes, leading to significant time consumption. This paper proposed a static analysis-based rapid fire following earthquake assessment method using simple information and implemented it in Pohang City, South Korea. Based on previous studies, the best-fit model for the ignition rate estimation was selected, and a cluster-based fire-burned rate estimation model was developed using simple building information (e.g., construction year, building occupancy, story, and total floor area) from the public building database (e.g., building registration data). For the fire-burned rate estimation model, fire-resistant structure types were defined using simple building information, and this was utilized to generate clusters of buildings at a regional level by comparing fire-spread distances for each fire-resistant structure type with adjacent distances among the buildings. This proposed method was applied to Pohang City, South Korea, and validated as follows: (1) the selected ignition rate model predicted similar ignition numbers to the actual reported number (actual number of ignitions = 4 vs. predicted number of ignitions = 3), and (2) the fire-burned rate model estimated fire-burned areas with a marginal difference compared to the fire spread simulation (fire-burned area using the proposed model = 13,703.6 m2 vs. results of fire spread simulation = 16,800.0 m2, with an error of approximately 18%). [ABSTRACT FROM AUTHOR]

Predictive models for spatial correlation play an effective role in the assessment of seismic risk associated with distributed infrastructure and building portfolios. However, existing models often rely on simplified approaches, assuming isotropy and stationarity. This paper verifies these assumptions by presenting a comprehensive study using a database of 3D physics-based simulated broadband ground motions for Istanbul, generated by the SPEED software. The results reveal significant event-to-event variability and nonstationary and anisotropic characteristics of spatial correlation influenced by source, path, and site effects. The development of nonstationary correlation models requires exploring influential metrics beyond spatial proximity and gaining a deep understanding of their impact, which is the focus of this study. Analysis of the spatial correlations of peak ground displacement, peak ground velocity, peak ground acceleration, and response spectral accelerations at different periods, employing both stationary and nonstationary correlation modelling methods and considering the finite fault model, indicates that the slip distribution pattern, direction and distance of station pairs relative to earthquake rupture, soil softness, and homogeneity of soil properties significantly influence the spatial correlations of near-field earthquake ground motions. Implementation of the introduced parameters in predictive spatial correlation models enhances the precision of regional seismic hazard assessments. [ABSTRACT FROM AUTHOR]

One hundred years ago, Fusakichi Omori died. Our paper is dedicated to his memory. Omori made an outstanding contribution to the physics of earthquakes. In 1894 he formulated the law of aftershock evolution. Omori's Law states that after the main shock of an earthquake, the frequency of aftershocks decreases hyperbolically with time. In this paper, we briefly describe one of the directions of modern aftershock research. We present Omori's law in the form of a differential equation describing the evolution of aftershocks. The evolution equation allows us to solve the inverse problem of the earthquake source "cooling down" after the main shock. The solution of the inverse problem allowed us to reveal the existence of the so-called Omori epoch. It is established that at the end of the Omori epoch something similar to a bifurcation of the source state occurs. A logistic equation supposedly describing the bifurcation phenomenon is proposed. [ABSTRACT FROM AUTHOR]

As electric vehicle (EV) adoption increases, transportation services will shift dependence from liquid fuel infrastructure to electric power infrastructure. Since transportation plays a major role in disaster response and recovery, this shift in dependence has important implications for coupling electrical grids and transport resilience. The implications for the electrical grid for southwestern British Columbia, Canada are examined, motivated by this region's high EV adoption rate and the potential for a catastrophic magnitude 9.5 earthquake. A comparison of the resilience of the electrical infrastructure compared to the fuel infrastructure is provided and approaches for increasing resilience in the region for EV power supply are discussed. This paper compiles lessons learned from past large earthquakes in Chile, Japan, and New Zealand with consideration given to successes and failures. While this paper was written with a focus on southwestern British Columbia, many of the suggestions for increasing power system resilience could be applied in other seismically active locations during the transition to EVs. This paper also considers integrated disaster resilience planning for the changing transport landscape from fuel vehicles to EVs. [ABSTRACT FROM AUTHOR]

This paper demonstrates the enhanced resilience performance of steel structures with viscoelastic friction dampers (VEFDs) based on numerical simulations of building responses. Velocity-dependent dampers, which are widely used to increase seismic resilience, may increase the axial force of the column under strong earthquake conditions because the generated force depends on the interstory velocity. This often leads to plastic hinges being placed on the columns of the structure, which can lead to structural collapse via weak-layer failure. In addition, while viscoelastic dampers are effective in reducing story drift, peak acceleration, and peak velocity, the proposed hybrid VEFD offers the additional benefit of reducing base shear via the friction damper. Simulation results for 10- and 20-story buildings with the novel VEFDs show that the proposed dampers can control drift and plastic deformation in structural members. Nonlinear dynamic analysis of 20 far-fault seismic ground motion records conducted using OpenSees also reveals lower peak absolute floor acceleration and velocity. Overall, the results suggest that the proposed VEFD has excellent potential for use in the performance-based seismic design of structures because it can reduce both structural and nonstructural damage. The results verify the damper's effectiveness in controlling story drift without a significant increase in the base shear. Collapse probability assessment also demonstrates the collapse resistance of moment-resisting frames when used in conjunction with VEFDs. [ABSTRACT FROM AUTHOR]

Sustainable development in urban areas requires a wide variety of current and theme-based information for efficient management and planning. In addition, researching the spatial distribution of earthquake (EQ) clusters is an important step in reducing seismic risks and EQ losses through better assessment of seismic hazards, therefore it is desirable to acquire an uncontaminated database of seismic activity. Quarry blasts (QBs) conducted over the mapped area have tainted the seismicity inventory in the northwestern region of Egypt, which is the focus of this paper. Separating these QBs from the EQs is hence preferable for accurate seismicity and risk assessments. Consequently, we present a highly effective ML model for cleaning up the seismicity database, allowing for the accurate delineation of EQ clusters using data from a single seismic station, "AYT", which is part of the Egyptian National Seismic Network. The magnitudes ≤ 3 that are very uncertain as EQs or QBs and need a significant amount of time to analyze are the primary focus of the model. In order to find the best way to classify EQs and QBs, the method looks at a number of ML models before settling on the best one using eight features. The results show that the suggested method, which uses the quadratic discrimination analysis model for discriminating, successfully separates EQs and QBs with a 99.4% success rate. [ABSTRACT FROM AUTHOR]

Earthquake-induced rock landslides in the eastern mountains of the Tibetan Plateau, especially landslides with weak interlayers pose a significant threat to major construction projects. Prestressed anchor cable is one of the main reinforcement methods of rock slopes. This paper combines shaking table model tests and numerical simulation to study the reinforcement effect and dynamic response characteristics of prestressed anchor cables applied to rock slopes with weak interlayers under strong earthquakes. The research results show that prestressed anchor cables can effectively reinforce slopes with weak interlayers. A small cable inclination, a small spacing and a high prestress are recommended in the seismic reinforcement design of prestressed anchor cable. In addition, the characteristics of slope progressive damage and prestress loss under the earthquake are found by the shaking table test. The results have been applied in hazard prevention and control of rock slopes on the Chengdu-Lanzhou Railway at the eastern Qinghai-Tibet Plateau. [ABSTRACT FROM AUTHOR]

Abstract—A source of a strong earthquake, as a rule, consists of subsources which are identified by waveform modeling. This modeling does not yield an unambiguous result. In this paper, we show an example when two significantly different focal mechanism solutions are presented for the same earthquake. In one solution, the subsources are characterized by similar faulting type, while in the other solution, the last subsource has an opposite mechanism. In (Vakarchuk et al., 2013), this discrepancy was interpreted as the realization of compensatory motion. The compensatory movements are detected not only in the subsources but also at the scale level of the source zone overall, where these movements manifest themselves in a certain regularity of the aftershock mechanisms discovered in the study of the 1970 Dagestan earthquake by Kuznetsova et al. (1976). In this paper, perhaps for the first time, compensatory movements are detected in a high-magnitude earthquake swarm lacking a pronounced main shock, which occurred in 2023 in Herat Province, Afghanistan. The results are supported by the set of the seismological and satellite interferometric data. [ABSTRACT FROM AUTHOR]

This paper delivers an in-depth bibliometric analysis of distributed acoustic sensing (DAS) research within the realm of geophysics, covering the period from 2012 to 2023 and drawing on data from the Web of Science. By employing bibliographic and structured network analysis methods, including the use of Bibliometrix and VOSviewer®, the study highlights the most influential scholars, leading institutions, and pivotal research contributions that have significantly shaped the field of DAS in geophysics. The research delves into key collaborative dynamics, unraveling them through co-authorship network analysis, and delves into thematic developments and trajectories via comprehensive co-citation and keyword co-occurrence network analyses. These analyses elucidate the most robust and prominent areas within DAS research. A critical insight gained from this study is the rise of 'photonic seismology' as an emerging interdisciplinary domain, exemplifying the fusion of photonic sensing techniques with seismic science. This paper also discusses certain limitations inherent in the study and concludes with implications for future research. [ABSTRACT FROM AUTHOR]

This paper serves as an introduction to focus on the meaning of resilience as a notion that hypothetically enables cities and their citizens to remain unaffected by shocks and stresses of diverse nature, but in practice, is a parsimonious representation of a highly complex human endogenous condition that is often not adequately understood and addressed due to weak or weathered disaster risk governance. Through an empirical analysis, the relevance of the occurrence of disasters such as the one produced by the Mexico City earthquake of September 19, 2017, and its relationship to the meaning of urban resilience is addressed. Since the 100 Resilient Cities program launch in 2013, several cities, including Mexico City, have adopted diverse strategies to build and become more resilient to physical, social, and economic shocks and stresses. Nonetheless, the degree of success of such strategies expressed in everyday life within the cities, regardless of what the official documents report, reveals highly heterogeneous results. In the case of Mexico City, it is evident that the appropriate strategy for attaining the desired outcome of becoming a Resilient City has not been successful. Despite setting the goal of advancing disaster risk reduction through urban and regional planning, the impact of the earthquake of September 19, 2017, proved otherwise. [ABSTRACT FROM AUTHOR]

The discovery of gas in Groningen in 1959 has been a massive boon to the Dutch economy. From the 1990s onwards, though, gas production has led to induced seismicity. In this paper, we carry out a comprehensive exploratory analysis of the spatio-temporal earthquake catalogue. We develop a non-parametric adaptive kernel smoothing technique to estimate the spatio-temporal hazard map and to interpolate monthly well-based gas production statistics. Second- and higher-order inhomogeneous summary statistics are used to show that the state-of-the-art rate-and-state models for the prediction of seismic hazard fail to capture inter-event interaction in the earthquake catalogue. Based on these findings, we suggest a modified rate-and-state model that also takes into account changes in gas production volumes and uncertainty in the pore pressure field. [ABSTRACT FROM AUTHOR]

On January 8, 2022, an M6.9 earthquake occurred in Menyuan, Qinghai, which caused surface damage. In this paper, the line-of-sight (LOS) coseismic surface deformation field is obtained by the interferometric synthetic aperture radar (InSAR) of the Sentinel-1 satellite. Constrained by the InSAR surface deformation field, a Bayesian method based on sequential Monte Carlo sampling was used to invert the geometric parameters of seismogenic faults and the distribution of fault slip. Moment magnitude of the model is Mw6.6. The earthquake was determined to occur at a left-lateral strike-slip fault. Based on the historical strong earthquake dislocation model, the PSGRN/PSCMP program was used to calculate the Coulomb stress change at the epicenter of the 2022 Menyuan M6.9 earthquake caused by the surrounding historical strong earthquakes. The results show that the occurrence of the Gulang M8 earthquake in 1927, the Menyuan Mw5.7 in 1986 and the Menyuan Mw5.9 earthquake in 2016 caused a significant increase in Coulomb stress at the epicenter of the 2022 Menyuan earthquake. The coseismic and post-seismic Coulomb stress increases were greater than 0.01 MPa. Combined analysis of this result with regional tectonic stress, allows us to conclude that the 2022 Menyuan M6.9 earthquake occurred on the dynamic background of the continuous extrusion of the Indian plate towards the Eurasian plate, and the regional historical strong earthquake activity played a significant role in promoting it. The research results provide a theoretical basis for understanding the seismogenic background and dynamic mechanism of the 2022 Menyuan earthquake. [ABSTRACT FROM AUTHOR]

Natural disaster risk assessment is of great significance to increasingly severe disaster prevention and mitigation work. However, the method of risk assessment for multi-disaster is still a difficult problem. In this paper, a novel multi-disaster risk assessment framework based on multi-dimensional correlation analysis is proposed, which combines numerical correlation, geographic correlation and multi-disaster correlation, from a more comprehensive point of view to give a reasonable multi-disaster risk assessment. Firstly, in the perspective of numerical correlation, gray correlation method is used to quantify and rank impact factors system data of natural disasters. Then, the factor detection module of geographic detector is used to detect the driving force of factors, which distributes the weights, based on the geographic correlation view. Finally, combining with above results, a multi-disaster coupling risk assessment model (MRAM) is established, which focus on multi-disaster correlation, to assess the integrated multi-disaster risk. The multi-disaster risk assessment framework is applied to evaluate the integrated risk of multiple natural disasters like flood, earthquake and storm surge in Tianjin City, China. The integrated risk is compared with the history natural disasters intensity and the risk results obtained by TOPSIS (Technique for Order Preference by Similarity to an Ideal Solution), which shows that the MRAM proposed is more reasonable to reflect the risk distribution. Furthermore, the framework is expected to be extended to multi-disaster risk assessment in other areas and contribute to building good disaster prevention and mitigation system. [ABSTRACT FROM AUTHOR]

The work presented in paper is focussed on the development of an accurate time-frequency representation of accelerograms, representing the seismic activity of the Himalayalan regions. The Himalayas have a long history of high levels of seismicity due to the movement of tectonic plates in the region. The effectiveness of the advanced time-frequency analysis (TFA) method known as Wavelet Synchro-Squeezed Transforms (WSST) has been exploited for processing accelerograms of the regions. Obtaining simultaneous time and frequency localizations with high levels of resolution is always challenging for non-stationary signals such as accelerograms. To have better time and frequency localization, the first part of the paper proposes an advanced TFA technique using WSST. The second part of work is then focused on devising a technique for accurate synthesis of the accelerograms to represent the actual and limited seismic records. A WSST based denoising is further proposed to remove the unwanted noise from the signals. Using the available actual recorded data from the region, respective synthetic accelerograms and response spectra have been developed for different magnitude and distance ranges using the WSST technique. The synthetic signals are then authenticated with the actual signal data using different Joint-TFA (JTFA) approaches. The effectiveness of the proposed WSST based synthesis method is further confirmed by higher structural similarity metric (SSIM) scores when compared with the time-frequency representations of the reference ground truth accelerograms. [ABSTRACT FROM AUTHOR]

Abstract—The paper presents the results of a study showing that anomalies in the seismic regime parameters before earthquakes of various magnitudes occur in stages. The occurrence in stages means the correlation between the times of formation and development of anomalies in various seismic regime parameters. Earthquakes in regions with two general types of tectonics are selected for analysis: in the subduction zone (Kamchatka and Japan) and in the rift zone (Iceland). The selection of regions is primarily based on the availability and quality of regional seismic catalogs. GR b-value and the composite parameter known as the RTL are used as the seismic regime parameters. The detection of spatiotemporal anomalies before the selected earthquakes is based on the known "precursory patterns" of the seismic regime parameters. Comparing the durations of the detected anomalies shows that the anomalies of b-value generally occur earlier than the RTL anomalies. Possible reasons why the anomalies occur in stages are suggested. In the vicinity of the studied earthquakes, a change in the seismogenic rupture concentration parameter within the corresponding seismic cycles is also estimated. Comparing the times at which the detected seismic regime anomalies occur with the values of the seismogenic rupture concentration parameter corresponding to these times shows that the formation of seismic regime anomalies occurs at a stage when the system of seismogenic ruptures accumulated during the seismic cycle has almost reached its critical value. [ABSTRACT FROM AUTHOR]

Liquefaction occurs when the ground experiences intense shaking due to seismic activities, causing water-saturated soils or loosely packed sediments near the surface to weaken and behave like a liquid. The present paper has reviewed and investigated the liquefaction around tunnels due to any seismic event that may occur during the tunnel's lifetime. To effectively prevent soil liquefaction around the tunnel, it is crucial to analyze both the acceleration response of the tunnel and the soil motion that results from liquefaction. This paper examines the geotechnical engineering aspects of such liquefactions and discusses analytic techniques to mitigate their effects. Also, the response of tunnel displacement under different magnitudes of earthquakes has been discussed. Different mitigation methods are explored in response to the damages caused by the liquefaction of soil due to earthquakes. Case studies of this problem that occurred in different nations were analyzed as well, amidst which are tunnel disasters in Turkey, Syria, China, Italy, Japan, India, and the USA. These instances demonstrate the terrible repercussions of liquefaction, such as building collapse, road network destruction, and surface and subsurface structure deterioration. By reviewing these instances, major patterns and trends in liquefaction-induced damages emerge, giving valuable insights for future mitigation and engineering practices. This review serves as a valuable resource for engineers and researchers involved in tunnel design, construction, and maintenance. This review paper addresses the dangers associated with liquefaction in soils and highlights the need for robust design considerations and appropriate construction techniques to mitigate potential damages. [ABSTRACT FROM AUTHOR]

The Samos Island (Aegean Sea) Earthquake occurred on 30 October 2020. It produced a tsunami that impacted coastal communities, ground shaking that was locally amplified in some areas and that led to collapse of structures with 118 fatalities in both Greece and Turkey, and wide-ranging geotechnical effects including rockfalls, landsliding, and liquefaction. As a result of the global COVID-19 pandemic, the reconnaissance of this event did not involve the deployment of international teams, as would be typical for an event of this size. Instead, following initial deployments of separate Greek and Turkish teams, the reconnaissance and documentation efforts were managed in a coordinated manner with the assistance of international partners. This coordination ultimately produced a multi-agency joint report published on the 2-month anniversary of the earthquake, and this special issue. This paper provides an overview of the reconnaissance activities undertaken to document the effects of this important event and summarizes key lessons spanning topic areas from seismology to emergency response. [ABSTRACT FROM AUTHOR]

On February 28th, 1969, a large earthquake (M SB w sb = 7.8) strokes the Iberian Peninsula and northern Morocco, producing some casualties and important damage and economic losses. This earthquake is the last large earthquake that has occurred in this region, very near where the catastrophic 1755 Lisbon earthquake took place. The paper by Udías ([11]) is a review of large tsunamigenic earthquakes that occurred at SW of Iberia before the 1755 Lisbon earthquake. [Extracted from the article]

Various geometric and mechanical conditions for soil–foundation interfaces affect the superstructure and foundation responses against earthquake. As one of these conditions, 2D asymmetry of soil around the embedded rigid foundation is emphasized in the present paper. Accordingly, a reduced-scaled embedded foundation bearing SDOF superstructure is considered under slow lateral cyclic and dynamic shake table tests in design and service levels at 1 g state, and the system response is compared to those of systems containing surface and embedded foundations with symmetric condition. Test results show the asymmetry in the moment–rotation response curve for system with asymmetric soil condition in static state. While for dynamic response, the behavior under harmonic excitation with the design amplitude level is close to one of system with surface foundation. In addition, the foundation moment capacity of nonlinear dynamic response can be estimated properly through theoretical expression for foundation with asymmetric condition. Moreover, the rocking behavior in two-way excitation causes significant loss of superstructure response relative to the foundation in all three cases. [ABSTRACT FROM AUTHOR]