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Abstract: Seismic tomography can provide both fine P-wave and S-wave velocity structures of the crust and upper mantle. In addition, with proper computation, Poisson’s ratio images from the seismic velocities can be determined. However, it is unknown whether Poisson’s ratio images have any advantages when compared with the P-wave and S-wave velocity images. For the purposes of this study, high-resolution seismic tomography under the eastern part of North China region was used to determine detailed 3-D crustal P- and S-wave seismic velocities structure, as well as Poisson’s ratio images. Results of Poisson’s ratio imaging show high Poisson’s ratio (high-PR) anomalies located in the Hengshan-North Taihang-Zhangjiakou (H-NT-Z) region, demonstrating that Poisson’s ratio imaging can provide new geophysical constraints for regional tectonic evolution. The H-NT-Z region shows a prominent and continuous high-PR anomaly in the upper crust. Based on Poisson’s ratio images at different depths, we find that this high-PR anomaly is extending down to the middle crust with thickness up to about 26km. According to rock physical property measurements and other geological data, this crustal Poisson’s ratio anomaly can be explained by Mesozoic partial melting of the upper mantle and basaltic magma underplating related to the lithospheric thinning of the North China craton. [Copyright &y& Elsevier]

Presents a study on the geothermal measurements in the pilot-boreholes of the China Continental Scientific Drilling. Results of the borehole temperature logging; Thermal conductivity of boreholes; Definition of territorial heat flow.

Cross-hole seismic tomography is a high-precision method that can obtain the velocity structure between boreholes. At present, single-component geophones are mainly used for P-wave velocity estimation. However, S waves have a shorter wavelength than P waves, incurring a high-resolution tomography image. In this paper, we apply three-component cross-hole seismic tomography to shallow geological survey. First, three-component geophone is used to collect cross-hole seismic data. Secondly, the apparent velocity polarization method is used to separate the P and S wavefields from the recorded three-component waveform data. Then, a damped least-squares traveltime tomography is used to calculate the cross-hole P- and S-wave velocity structures. Finally, the distribution of Poisson's ratio between the boreholes is derived from the inverted P- and S-wave velocities. Numerical model experiments show that this method can solve some typical shallow subsurface problems, such as the detection of karst features and boulders. The proposed method is used to detect an underground air-raid shelter located in Hangzhou, Zhejiang Province, China, and the P- and S-wave velocities and the Poisson's ratio are obtained with high precision. The tomography image of the air-raid shelter agrees well with its known location. and the calculated Poisson's ratio distribution shows that the air-raid shelter may be partially filled with mucky clay. Three-component cross-hole seismic tomography achieves a high data acquisition efficiency and can simultaneously obtain shallow subsurface stratum velocities and Poisson's ratio with high precision. Thus, this technique can be used for shallow-subsurface surveys. • Apply three-component cross-hole seismic tomography to shallow geological survey. • Acquire P and S wave velocity parameters and poisson's ratio at the same time. • Experiments have proved its high-precision imaging ability in shallow surface. [ABSTRACT FROM AUTHOR]

Groundwater is a potentially significant resource for agricultural and industrial uses in Tarim Basin, the largest arid endorheic basin in China. Hydrogeochemical and hydrogeologic researches have provided detailed information of groundwater chemical type, composition, ion content and flow. However, there is lacking in quantitative estimation of groundwater in whole basin scale subject to the limits of samples as well as the unclear underground structure. To address the problem, 3-D electrical resistivity model constructed from inversion of magnetotelluric (MT) data was used to calculate the Total Dissolved Solids (TDS) of groundwater based on previous experimental studies and empirical equations. The TDS model shows relatively high value in the east of the study area and in deep, primarily controlled by depth, flow direction, stratigraphy, and water table gradient. Groundwater can be classified into five categories in terms of TDS range in Standard for Groundwater Quality. Finally, the volume of each type and average available quantity of Classes I ∼ III (TDS < 1 g/L) per person were estimated by taking account of population distribution. Mapping groundwater TDS and volume reveals that human activities also play a role in groundwater salinity. The evaluation of groundwater quality and volume based on TDS provides a basis for future urban construction and development as well. We estimated the total dissolved solids (TDS) of groundwater of the Quaternary aquifer in Northern Tarim and found that its distribution is mainly controlled by flow direction, while human activities also have a certain impact. Freshwater is concentrated in the western and northeastern regions, providing reference for future urban construction. [Display omitted] • 3-D resistivity model in Tarim Basin inverted from magnetotelluric data. • Groundwater TDS and volume estimated at big basin-scale. • Water table gradient, depth and stratigraphy affect TDS distribution. • Human activities have some impacts on groundwater salinity. • Groundwater evaluation based on TDS provides a basis for future urban development. [ABSTRACT FROM AUTHOR]

• 756 magnetotelluric data were inverted in the Tarim basin by 3-D MGS inversion scheme. • 3-D electrical conductivity structure in the Tarim basin was obtained. • The crystalline basement of the Tarim basin is divided into three types of basement. • The Tarim basin possesses the attributes of a cratonic basin. • The variable lithosphere depth distribution of the Tarim basin was obtained for the first time. The Tarim basin, located in northwestern China, is the largest inland basin with oil, gas, and mineral resources in China. To study the deep structure of the Tarim basin, we conducted a magnetotelluric (MT) survey of the entire basin using 756 datasets to build a three-dimensional (3-D) electrical conductivity model. Based on the initial 3-D model, which was derived from a two-dimensional (2-D) minimum support gradient (MSG) inversion, the electrical conductivity structure of the Tarim basin was imaged by a 3-D MT regularized inversion using the contracting integral equation method (CIE) and quasi-Newton optimization. Based on simulation results, a thick resistive anomaly exists near the center of the Tarim basin, which suggests that the basin has the properties of a cratonic basin. The basin is also surrounded by resistive lithosphere faults, which indicates that it has the properties of a fault basin. The crystalline basement of the Tarim basin is divided into a resistive craton basement, high resistance basalt basement, and conductive crevice water metamorphic basement based on the shallow resistivity structure. In addition, the lithospheric thickness was estimated using the deeper resistive structure. [ABSTRACT FROM AUTHOR]

The quantitative analysis of the urban-rural integration development (URID) level and its driving factors is of great significance for the new-type urbanization of urban agglomerations. This study constructed a multidimensional framework in the perspective of a population-space-economy-society-ecology framework to measure the URID level from 2000 to 2020 and further explored the driving mechanism of the URID changes by a geographical detector model in the Hangzhou Bay urban agglomeration (HBUA). The results showed that the land-use change in the HBUA from 2000 to 2020 showed a typical characteristic of the transition between cultivated and construction land. The URID level in the HBUA improved from 0.294 in 2000 to 0.563 in 2020, and the year 2005 may have been the inflection point of URID in the HBUA. The URID level showed a significant spatial aggregation with high values. Hangzhou, Jiaxing, and Ningbo were hot spots since 2015, and the cold spots were Huzhou and Shaoxing. The population and spatial integration had more important impacts on URID levels in 2000, 2005, and 2020, while economic and social integration had more significant impacts on URID levels in 2010 and 2015. This study provided a deeper understanding of the evolution of URID in an urban agglomeration and could be used as a reference for decision makers.

The production of cash crops is often regarded as an effective way to increase farmers' income. This study evaluates the impact of non-food cultivation of cropland on farmers' income by using the least-squares (OLS) model in Zhejiang Province, eastern China. Farmers are further divided into different groups according to their income levels to analyze the different impacts of non-food cultivation on their household income. The result shows that non-food cultivation has a significant negative effect on farmers' income, with a more pronounced effect on farmers with a relatively low income. Accordingly, the increase in the proportion of cash crops that are grown does not increase the income of farmers in Zhejiang; instead, this harms their income. Therefore, farmers in Zhejiang should not rely on the cultivation of cash crops for their prosperity but must focus on participating in non-farm employment to increase their household income.