Evolution characteristics of Quaternary tectonic stress field in the north and east margin of Qinghai-Xizang plateau

1999 ◽  
Vol 12 (5) ◽  
pp. 550-561 ◽  
Author(s):  
Fu-Ren Xie ◽  
Shi-Min Zhang ◽  
Su-Qin Dou ◽  
Xiao-Feng Cui ◽  
Sai-Bing Shu
2020 ◽  
Author(s):  
Guangyin Xu ◽  
Qing Wu ◽  
Suyun Wang

<p>The Ngari area in Tibet is in the forefront of land-continent collisions. The area is accompanied by the polymerization of plates, forming complex structures such as the Tethys Himalayan pleat belt, the Yarlung Zangbo suture belt, and the Gangdese continental margin magma arc from the south to the north. The multi-period dive collision-inland convergence process, the geological structure is complex and the seismicity is very high. Based on the Chinese historical earthquake catalogue, the China Modern Earthquake Catalogue and the seismic data from the International Seismological Center (ISC), we analyzed the seismic activity, focal mechanism and modern tectonic stress field in the Ngari area, and then analyzed the seismicity and its source of geodynamics. The main conclusions are as follows:(1) The seismic activities in the Ngari area are mainly distributed in the Himalayan tectonic belt, the Bangong-Nujiang tectonic belt, the Alkin-East Kunlun tectonic belt, and some near north-south trending tectonic belts; (2) Earthquakes near the Himalayan tectonic belt is dominated by reverse faulting events. The seismic activity near the Bangong-Nujiang tectonic belt and the Alkin-East Kunlun tectonic belt is dominated by strike-slip earthquakes. Near the north-south extensional tectonic belt, the earthquakes show as the normal faulting events. (3) The main direction of the modern tectonic stress field in the study area is near north-south direction; (4) Seismic activity, focal mechanism and modern tectonic stress field show that the geodynamic source in the Ngari region is from Collision and squeezing the between the Eurasian plate and the Indian Ocean plate.</p>


2018 ◽  
Vol 9 (3) ◽  
pp. 1025-1037
Author(s):  
D. A. Safonov

The Amur region (Priamurie) is located in the NE part of the Amur lithospheric plate and its surrounding territories. Seismic activity is moderate in Priamurie, and the regional earthquakes, including the strongest ones, occur mainly in three seismic belts: Stanovoi (the zone of influence of the eastern flank of the Stanovoi fault), Yankan-Tukuringra-Soktakhan (the eastern flank of the Mongolia-Okhotsk lineament), and Turan-Selemzhinsky (from the Lesser Khingan to the north). The Sakhalin Branch of FRC GS RAS Catalogue of focal mechanisms of 57 regional earthquakes provide the data for a more precise estimation of the parameters of the crustal stress state in the study area. The Cataclastic Analysis Method (CAM) developed by Yu.L. Rebetsky (stage 1) was used to estimate the orientations of the main axes of the stress tensor and the Lode – Nadai coefficient. The analysis shows that the Upper Priamurie is dominated by shearing and compression with shearing. The Amur plate moves relative to the Aldan-Stanovoi block along the South Tukuringra and North Tukuringa faults to the east. Vertical shearing is predominant along the Dzheltulak fault and the western segment of the North Tukuringra fault. The NNE-trending compression takes place in the area located east of the quiescence zone of the Dzhagda ridge. Along the Mongolia-Okhotsk fault system, near the Sea of Okhotsk, the direction of compression changes to the northward one. The tectonic stress field along the Tanlu fault zone is inhomogeneous and comprises the alternating zones of horizontal compression and stretching with varying directions of the main stress axes. To the east of the band characterized by the maximum seismic activity, compression changes its direction to the southeast- and eastward. Probably, the impact of the oceanic subduction on the northern part of the Japan-Korean block begins to manifest itself in this part of the Amur region. The tectonic stress field reconstructed from the seismological data is consistent with the measurements of the modern crustal movements. The results of our study can prove useful for clarifying the tectonics of the region. 


2013 ◽  
Vol 864-867 ◽  
pp. 2418-2421
Author(s):  
Li Yang ◽  
Jian Lin Li ◽  
Shi Wei Luo

The tectonic stress field plays an important role in the research of crustal stability, fault activity and the geological disaster effect. On the basis of related geological data, ANSYS and FLAC3D are applied in this paper to set up a reasonable geological structure model and boundary conditions, aiming at making a numerical simulation analysis of tectonic stress field in the southeast of the Qinghai-Tibet plateau. The result and the measured data fit better, which provides a reference for the further study of the project.


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