Second Crust Monitoring and Application Center

CEA, China

Second Crust Monitoring and Application Center

CEA, China
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Li Y.,Institute of Geology | Li Y.,Second Crust Monitoring and Application Center | Cui D.,Second Crust Monitoring and Application Center | Hao M.,Second Crust Monitoring and Application Center
Diqiu Kexue - Zhongguo Dizhi Daxue Xuebao/Earth Science - Journal of China University of Geosciences | Year: 2015

GPS mwasurements can provide a high accuracy of spatio-temporal images, but there aren't enough study about it. We use the spherical linear block theory constrained by geodetic observations from Global Positioning System (GPS) stations to estimate fault slip rates on the Northeastern margin of Tibet plateau and spatially variable coupling on Haiyuan fault in abroad sense. The 3D geometric block model is based on the previous researches of active block. The result provides a new constraint and reference for the geodynamics of present crustal deformation and the middle-long term strong earthquake hazard study in this area. ©, 2015, China University of Geosciences. All right reserved.

Yang C.,Chang'an University | Yang C.,Key Laboratory of Western China Mineral Resources and Geological Engineering | Zhang Q.,Chang'an University | Zhang Q.,Key Laboratory of Western China Mineral Resources and Geological Engineering | And 5 more authors.
Mining Science and Technology | Year: 2010

For harmful ground collapse and its special deformation characteristics, which causes SAR images to lose coherence, InSAR technology cannot be applied in monitoring surface collapse in mining areas. We took the Shenmu mining area in northern Shaanxi province as an example to study subsidence in mining areas and proposed an interpolated multi-view processing method. The results show that this method can improve the detectable deformation gradient to a certain extent and can become a good reference value for monitoring large scale gradient deformation. We also analyzed the rules for temporal decorrelation in mining. © 2010 China University of Mining and Technology.

Ji L.,Second Crust Monitoring and Application Center | Hu Y.,Second Crust Monitoring and Application Center | Wang Q.,Second Crust Monitoring and Application Center | Xu X.,China Earthquake Administration | Xu J.,Second Crust Monitoring and Application Center
Journal of Geodynamics | Year: 2015

Ground surface deformation monitoring is important for understanding regional crustal movement. However, in eastern Hainan Island, China, few near-field geodetic observations are available; thus, the in situ crustal movement remains poorly understood. In this study, the deformation field of the eastern Hainan Island region was captured from 2007 to 2011 by applying the stacking-InSAR approach to ALOS PALSAR images. The results exhibit a trough deformation pattern that extends along the small to moderate earthquake belt with a maximum peak-to-trough range change rate of approximately 9. mm/year. We propose that a magma-fed dyke is responsible for the observed surface deformation pattern. The modeled dyke is approximately 54. km long, 1. km wide, dipping 71° to the west, centered 25. km fixed during modeling beneath eastern Hainan Island, and strikes nearly N-S, parallel to the elongated pattern of seismicity in the area. We infer that the regional stress field favors the formation of dyke beneath eastern Hainan Island; consequently, the intruding magma has accumulated in an elongated, dyke-like storage zone. The zone dilated progressively over time, accompanied by sporadic earthquakes and subtle surface deformation. © 2015 Elsevier Ltd.

Liu W.-Y.,Second Crust Monitoring and Application Center
Earthquake | Year: 2012

Prof. Chen Xinlian devoted himself into earthquake-related research and management from 1968.After spending over half of his life working in related fields, he has got great success and stands out as the initiator, founder and pioneer of the discipline of crustal deformation in China, and become an honored expert and famous scientist in dynamic geodesy. Prof. Chen is a key person with strategic vision and is good at top-design capability, he has also been a problem solver in the field of earthquake preparation and disaster mitigation. This paper reviews Prof. Chen's academic thoughts in learning and managing crustal deformation, earthquake-related policy and safety.

Zhu Y.-Q.,Second Crust Monitoring and Application Center | Liu F.,Second Crust Monitoring and Application Center | Fu G.-Y.,Institute of Earthquake Science | Zhao Y.-F.,Second Crust Monitoring and Application Center
Earthquake | Year: 2012

Temporal-spatial evolution of gravity field before the Wenchun M S8.0 earthquake has been analyzed systematically by integrally adjusting the gravity observation data from the northeastern edge of the Tibetan Plateau. The results show that deep material of Tibetan Plateau moved northeastward after Wenchun M S8.0 earthquake, and some channels have been blocked by the Ordos block. Regional gravity field has changed significantly on a large spatial scale. After the Wenchun earthquake, gravity field changed non-uniformly between Liupanshan fault zone which borders land of Gan-Ning-Shan and the fault zone along the north edge of west Qinling mountains. This area has been affected by the Wenchun earthquake significantly.

Zhang S.-X.,Second Crust Monitoring and Application Center | Zhang X.,Second Crust Monitoring and Application Center
Earthquake | Year: 2012

In order to investigate seismicity in the peripheral areas of the Ordos block after the 2008 Wenchuan earthquake, we analyzed evolutive course of the current vertical deformation in the Fenwei fault-depression zone using fault-crossing leveling data situated on different locations. The following are obtained: 1: The vertical movement extent of ascending and sinking difference is about 20 mm, and there is no obvious exceptional deformation; 2: Small earthquake activities may be transient instability of horizontal stress field of Ordos block, due to adjustment of compressional stress from Qinghai-Tibet plate and relative strengthening of compressional stress from North China sub-plate.

Zhou C.,Second Crust Monitoring and Application Center | Wang Q.-L.,Second Crust Monitoring and Application Center | Wang S.-X.,Second Crust Monitoring and Application Center
Earthquake | Year: 2014

Because of the existence of geological structure such as fractures and small cracks in the earth, there are some nonlinear phenomena, which are similar to solitary waves in observed seismic data. Studies on solitary waves in solid media can help to explain their formation mechanism. Based on the KdV equation, using Ricker wavelet as initial condition and dilaton mechanism to construct body force, we simulated solitary waves in detail by finite difference method. Theoretical results indicate that solitary waves could be evolved from Ricker wavelet, and initial amplitude of seismic wave and dispersion coefficient can significantly influence the evolution process. The observed seismic data in this paper can also illustrate the possibility of this kind of evolution. In addition, according to the zonal distribution of the coefficient matrix, sparse matrix access method has been used, which can reduce the computation memory and improve the calculation efficiency.

Guo S.S.,Second Crust Monitoring and Application Center | Zhu Y.Q.,Second Crust Monitoring and Application Center | Zhao Y.F.,Second Crust Monitoring and Application Center
Applied Mechanics and Materials | Year: 2014

The gravity data from 1998 to 2012 in eastern margin of Tibetan Plateau was processed to analysis the relation between gravity field and earthquake activities. The results show that long period gravity change appears to be concentrated in regions with active faults, and short term variation may be affected by change of the active tectonic in eastern margin of Tibet plateau that due to energy release and adjustment after Wenchuan Ms 7.9 and Yushu Ms 7.1 earthquake. Specifically, gravity field alternated with positive and negative from 2010 to 2011 reflects viscoelastic properties of coseismic deformation after Wuchuan earthquake; a restorational change from negative to positive during 2011-2012 provides support crust tectonics exists strain accumulate and release stage in regions. © (2014) Trans Tech Publications, Switzerland.

Yang C.-S.,Chang'an University | Zhang Q.,Chang'an University | Zhao C.-Y.,Chang'an University | Wang Q.-L.,Second Crust Monitoring and Application Center | Ji L.-Y.,Second Crust Monitoring and Application Center
Journal of Geodynamics | Year: 2014

The Datong Basin is located to the north of the Fenwei Graben Basin, where ground fissures and subsidence are common geological hazards. The Datong Basin is also one of China's main energy bases and is known as "the hometown of coal". In this study, the small baseline subset InSAR technique was used to process 40 scenes of Envisat ASAR images that cover this area. The magnitude and distribution of subsidence in the Datong Basin were obtained. Additionally, the relationships among the regional land subsidence, ground fissures and fault activity were addressed. The results reveal that Datong ground subsidence is affected by the groundwater exploitation and the nearby faults. The Datong ground fissures are controlled by regional fault activity (e.g., seismic activity) and its interaction with the ground subsidence. Meanwhile, the influence of surface precipitation on ground fissure activity was analyzed. The differential subsidence on both sides of the ground fissures was also studied. © 2014 Elsevier Ltd.

Zhu Y.-Q.,Second Crust Monitoring and Application Center | Zhu Y.-Q.,CAS Wuhan Institute of Geodesy and Geophysics | Wen X.-Z.,Institute of Earthquake Science | Sun H.-P.,CAS Wuhan Institute of Geodesy and Geophysics | And 2 more authors.
Chinese Journal of Geophysics (Acta Geophysica Sinica) | Year: 2013

Using the observation data of relative gravity measurements in western Sichuan region from 2010 to 2012, we have systematically analyzed the spatial-temporal variation of the regional gravity field and their relation to the occurrence of the Ms=7.0 Lushan earthquake on April 20, 2013. Our research mainly shows that: (1) Spatially the anomaly change of the regional gravity field is closely related to both the southern segment of the NE-trending Longmenshan fault zone and the NNW-trending Markang fault, suggesting that the active tectonic action or deformation happened along the two fault zones (or segments) during 2010 to 2012, which would have induced the variation in the ground gravity observation. (2) Before the Ms=7.0 Lushan earthquake, regional gravity anomaly appeared in the whole study region and local gravity anomalies at and near the potential source area. Among the region and the areas with gravity anomalies, the anomaly variations near Baoxing, Tianquan, Kangding, Luding and Shimian were up to and over 100×10-8m·s-2, apparently reflecting an enhancement of tectonic or stress's action in the study region and at and near the potential source area, that could be related to the preparation and occurrence of the earthquake. (3) The dynamic evolution patterns of the regional gravity changes and those patterns of cumulated gravity variations suggest that significant anomalies of gravity variations in the relative gravity measurements appeared indeed in the last 2 to 3 years in the preparation of the Ms=7.0 Lushan earthquake, and such anomalies can be regarded as one of the medium-term precursory of the earthquake. In a certain degree, the first author of this paper and others once made a medium-term forecast before the Lushan earthquake, especially made a forecast for the locality of the earthquake based on the anomaly gravity variations. The case studied in this article demonstrates again that through relative gravity survey people can catch anomalous gravity variation that would be related to the process of earthquake preparation, especially to those anomaly variations appearing in the last stage of the process. Therefore, relative gravity survey has unique advantages in the medium- to long-term earthquake forecast, especially for forecasting localities of potential earthquakes.

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