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Numerical analysis of contemporary hori-zontal tectonic deformation fields in China from GPS data

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Acta Seismologica Sinica(English Edition) 2005年第2期18卷 135-146,254页

作者：杨少敏王琪游新兆 GPS Laboratory Institute of SeismologyChina Earthquake AdministrationWuhan 430071China

Assuming that the contemporary tectonic activity in China can be treated as continuous, we have simulated 1245 present-day multiple-epoch GPS velocity solutions in the range of Chinese mainland, Mongolia, Myanma, India, Nepal and Himalayas with a bi-cubic spline interpolation function to inverse the integral horizontal velocity with the fitting accuracy less than 3 mm and obtained the strain rate fields in Chinese mainland. We have also analyzed the characteristics of spatial distribution of horizontal deformation and strain rate fields in Chinese mainland. The result shows that the analysis on the continuous deformation in the large-scale and dense GPS velocity fields can reveal not only the integral tectonic characters of Chinese mainland but also the tectonic characters in local regions. Generally, the magnitude and intensity of horizontal tectonic deformation have a mutation in the South-North Seismic Belt (95°E-102°E), which is stronger in the west than the east and stronger in the south than the north. Large strain rates are found in the areas as Kunlun block, Xianshuihe fault zone and central Yunnan, and the variation of velocity is very rapid. At the same time, the tectonic activity is relatively calm on Altyn Tagh fault zone, and extensive strain is found in the eastern part of central Tianshan.

关键词： GPS tectonic deformation horizontal strain rate fields

Late Quaternary tectonic deformation of the Eastern End of the Altyn Tagh Fault

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Acta Geologica Sinica(English Edition) 2015年第6期89卷 1813-1834页

作者： YU Zhongyuan MIN Wei CHEN Tao LIU Yugang SU Peng Key Laboratory of Active tectonics and Volcanoes Institute of GeologyChina Earthquake Administration Earthquake Administration of Heilongjiang Province Key Laboratory of Active tectonics and Volcanoes Institute of GeologyChina Earthquake Administration Earthquake Administration of Zhejiang Province

The Quaternary activity of the faults at the eastern end of the Altyn Tagh fault, including the Dengdengshan-Chijiaciwo, Kuantanshan and Heishan faults, was studied on the basis of interpretation of satellite images, trenching, geomorphologic offset measurements and dating. The Altyn Tagh fault has extended eastwards to Kuantanshan Mountain. The left-slip rates of the Altyn Tagh fault decreased through the Qilianshan fault and were transformed into thrust and folds deformation of many NW-trending faults within the Jiuxi basin. Meanwhile, under NE-directed compression of the Tibetan plateau, thrust dominated the Dengdengshan-Chijiaciwo fault northeast of the Kuantanshan uplift with a rate lower than that of every fault in the Jiuxi basin south of the uplift, implying that tectonic deformation is mainly confined to the plateau interior and the Hexi Corridor area. From continual northeastward enlargement of the Altyn Tagh fault, the Kuantanshan uplift became a triangular wedge intruding to the east, while the Kuantanshan area at the end of this wedge rose up strongly. In future, the Altyn Tagh fault will continue to spread eastward along the Heishan and Jintananshan faults. The results have implications for understanding the propagation of crustal deformation and the mechanism of the India-Eurasian collision.

关键词： slips rate tectonic deformation Kuantanshan fault Dengdengshan fault Altyn Tagh fault

KINEMATIC FEATURES OF tectonic deformation OF TERRANES IN THE XIZANG (TIBETAN) TETHYAN BELT

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地震地质 1992年第3期 204-214页

作者： Shen Xianjie(Institute of Geology,Academia Sinica,Beijing 100029)

From the point of view of plate kinematics a unified convergence velocity model is employed to derive a series of kinematic equations for deformation of Himalaya and Lhasa-Gangdise terranes during the Himalayan orogeny.These equations describe terrane shortening,crust-upper mantle thickening,lateral strike-slip movement,plateau surface uplift,erosion planation and isostatic height of the crust,etc.These kinematic equations for terrane deformation derived on the basis of mass conservation define the macroscopic trends of tectonic evolution of 2-D deformation of the Himalaya Terrane and 3 D deformation of the Lhasa-Gangdise Terrane during the 40Ma of the Indian-Eurasian convergence-collision on the one hand,and provide the systematically defined initial and boundary conditions for further study on the process of tectono-thermal evolution of the deformed terranes on the other hand.

关键词： Tethyan Belt Terranes tectonic deformation Plate kinematics Mass conservation Xizang

Multi-layer tectonic Model for Intraplate deformation and Plastic-Flow Network in the Asian Continental Lithosphere

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Acta Geologica Sinica(English Edition) 1993年第3期67卷 247-271页

作者： Wang Shengzu Institute of Geology, State Seismological Bureau, Beijing Liu Linqun

In a large area of the east—central Asian continent there is a unified seismic network system composed of two families of large—seismic belts that intersect conjugately. Such a seismic network in the middle—upper crust is actually a response to the plastic flow network in the lower lithosphere including the lower crust and lithospheric mantle. The existence of the unified plastic flow system confirms that the driving force for intraplate tectonic deformation results mainly from the compression of the India plate, while the long-range transmission of the force is carried out chiefly by means of plastic flow. The plastic flow network has a control over the intraplate tectonic deformation.

关键词： Continental lithosphere tectonic deformation multi-layer tectonic model large-scale seismic belt seismic network plastic flow network

Soil bentonite wall protects foundation from thrust faulting: analyses and experiment

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Earthquake Engineering and Engineering Vibration 2013年第3期12卷 473-486页

作者： Meysam Fadaee I. Anastasopoulos G. Gazetas M.K. Jafari M. Kamalian International Institute of Earthquake Engineering and Seismology School of Civil Engineering National Technical University

When seismic thrust faults emerge on the ground surface, they are particularly damaging to buildings, bridges and lifelines that lie on the rupture path. To protect a structure founded on a rigid raft, a thick diaphragm-type soil bentonite wall （SBW） is installed in front of and near the foundation, at sufficient depth to intercept the propagating fault rupture. Extensive numerical analyses, verified against reduced-scale （1 g） split box physical model tests, reveal that such a wall, thanks to its high deformability and low shear resistance, ＂absorbs＂ the compressive thrust of the fault and forces the rupture to deviate upwards along its length. As a consequence, the foundation is left essentially intact. The effectiveness of SBW is demonstrated to depend on the exact location of the emerging fault and the magnitude of the fault offset. When the latter is large, the unprotected foundation experiences intolerable rigid-body rotation even if the foundation structural distress is not substantial.

关键词： soil bentonite wall fault rupture soil-structure interaction seismic hazard mitigation tectonic deformation soil-foundation interaction

Characteristics of Mesozoic-Cenozoic tectonic diagenesis in the Kuqa area of the Tarim Basin,China

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Petroleum Science 2009年第4期6卷 366-375页

作者： Jianfeng Shou Yang Shen Huiliang Zhang Ronghu Zhang PetroChina Hangzhou Res Inst Petr Geol Hangzhou 310023 Zhejiang Peoples R China

tectonic diagenesis is a common and important geological phenomenon. We can fully understand the diagenesis of compressional basins through studying tectonic diagenesis. In this paper, we presented the tectonic diagenetic characteristics in the Kuqa area of the Tarim Basin by integrated method of geological analysis and paleotectonic stress. The results showed that the Mesozoic-Cenozoic tectonic diagenesis affected sandstone compaction evolution mainly through physical mechanisms. It showed characteristics of abrupt change and nonthermal indicator (it means that sandstone compaction can not be explained by thermal diagenetic compaction alone because actual sandstone compaction was larger than thermal compaction), which were different from the thermal and fluid diagenesis. Compared with thermal diagenesis, tectonic diagenesis had a typical tectonic compaction in very short time, and many phases of tectonic deformation showed multiple abrupt changes of compaction. There are obvious differences between tectonic and thermal diagenetic compaction, leading to sandstone compaction being larger than the thermal compaction under the same thermal evolution stage in the areas where tectonic deformation happened. The stronger the tectonic deformation, the more obvious the difference. tectonic process changed the stress distribution through changing the tectonic deformation styles, resulting in different tectonic diagenesis effects. Therefore, tectonic diagenesis of Mesozoic-Cenozoic in the Kuqa area can be divided into four types including rigid rock restraint, fault ramp, low angle fault slippage, and napping.

关键词： Sandstone reservoirs tectonic deformation tectonic diagenesis controlling factors Kuqa area

Gravity variation before Kunlun mountain pass western M_s=8.1 earthquake

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Acta Seismologica Sinica(English Edition) 2003年第3期16卷 304-311页

作者：祝意青王双绪江在森朱桂芝李辉张永志 The Second Crustal deformation Monitoring Center China Seismological BureauXi'an 710054China The Second Crustal deformation Monitoring Center China Semsmological BureauXi'an 710054China Center for Analysis and Prediction China Seismological BureauBeijing 100036China Institute of Seismology China Seismological BureauWuhan 430071China

The relation between the gravity variation features and Ms=8.1 earthquake in Qinghai-Xizang monitoring area is analyzed preliminarily, by using spatial dynamic variation results of regional gravity field from absolute gravity and relative gravity observation in 1998 and 2000. The results show that: 1) Ms=8.1 earthquake in Kulun mountain pass western occurred in the gravity variation high gradient near gravit/s high negative variation; 2) The main tectonic deformation and energy accumulation before Ms=8.1 earthquake are distributed at south side of the epicenter; 3) The range of gravity's high negative variation at east of the Ms=8.1 earthquake epicenter relatively coincides with that rupture region according to field geology investigation; 4) Gravity variation distribution in high negative value region is just consistent with the second shear strain's high value region of strain field obtained from GPS observation.

关键词： absolute gravity relative gravity Ms=8.1 earthquake tectonic deformation

Main controlling factors and enrichment area evaluation of shale gas of the Lower Paleozoic marine strata in south China

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Petroleum Science 2015年第4期12卷 573-586页

作者： Xian-Ming Xiao Qiang Wei Hai-Feng Gai Teng-Fei Li Mao-Lin Wang Lei Pan Ji Chen Hui Tian State Key Laboratory of Organic Geochemistry Guangzhou Institute of Geochemistry Chinese Academy of Sciences University of Chinese Academy of Sciences

The Lower Paleozoic shale in south China has a very high maturity and experienced strong tectonic defor- mation. This character is quite different from the North America shale and has inhibited the shale gas evaluation and exploration in this area. The present paper reports a com- prehensive investigation of maturity, reservoir properties, fluid pressure, gas content, preservation conditions, and other relevant aspects of the Lower Paleozoic shale from the Sichuan Basin and its surrounding areas. It is found that within the main maturity range （2.5 % 〈 EqRo 〈 3.5 %） of the shale, its porosity develops well, having a positive cor- relation with the TOC content, and its gas content is con- trolled mainly by the preservation conditions related to the tectonic deformation, but shale with a super high maturity （EqRo 〉 3.5 %） is considered a high risk for shale gas exploration. Taking the southern area of the Sichuan Basin and the southeastern area of Chongqing as examples of uplifted/folded and faulted/folded areas, respectively, geo- logical models of shale gas content and loss were proposed. For the uplifted/folded area with a simple tectonic defor- mation, the shale system （with a depth 〉 2000 m） has lar- gely retained overpressure during uplifting without a great loss of gas, and an industrial shale gas potential is generally possible. However, for the faulted/folded area with a strong tectonic deformation, the sealing condition of the shale system was usually destroyed to a certain degree with a great loss of free gas, which decreased the pressure coefficient and resulted in a low production capacity. It is predicted that the deeply buried shale （〉3000 m） has a greater gas potential and will become the focus for further exploration and development in most of the south China region （outside the Sichuan Basin）.

关键词： Lower Paleozoic shale gas Maturity Maincontrolling factors tectonic deformation

Heterogeneous strain regime in the eastern margin of Tibetan Plateau and its tectonic implications

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Earthquake Science 2015年第1期28卷 1-10页

作者： Guojie Meng Xiaoning Su Weiwei Wu Jinwei Ren Yonglin Yang Jicang Wu Chieh-Hung Chen Nikolay V.Shestakov Division of Earthquake deformation Institute of Earthquake ScienceChina Earthquake Administration Key Laboratory of Earthquake Prediction Institute of Earthquake ScienceChina Earthquake Administration Engineering Institute of Surveying and Mapping Earthquake Administration of Sichuan Province Tongji University ‘‘National’’ Chung Cheng University Institute of Applied Mathematics Far Eastern Branch of Russian Academy of Sciences

The eastern margin of Tibetan Plateau is one of the most active zones of tectonic deformation and seismicity in China. To monitor strain buildup and benefit seismic risk assessment, we constructed 14 survey-mode global position system （GPS） stations throughout the northwest of Longmenshan fault. A new GPS field over 1999-2011 is derived from measurements of the newly built and pre-existing stations in this region. Sequentially, two strain rate fields, one preceding and the other following the 2008 MwT.9 Wenchuan earthquake, are obtained using the Gausian weighting approach. Strain field over 1999-2007 shows distinct strain partitioning prior to the 2008 MwT.9 Wenchuan earthquake, with compression spreading over around Longmenshan area. Strain fieldderived from the two measurements in 2009 and 2011 shows that the area around Longmenshan continues to be under striking compression, as the pattern preceding the Wenchuan earthquake, implying a causative factor of the sequent of 2013 Mw6.7 Lushan earthquake. Our GPSderived dilatation shows that both the Wenchuan and Lushan earthquakes occurred within the domain of pro- nounced contraction. The GPS velocities demonstrate that the Longriba fault underwent slight motion with the faultnormal and -parallel rates at 1.0 -4- 2.5 mm and 0.3 4-2.2 mm/a; the Longmenshan fault displayed slow activity, with a fault-normal rate at 0.8 ± 2.5 mm/a, and a fault-parallel rate at 1.8 4- 1.7 mm/a. Longriba fault is on a par with Longmenshan fault in strain partitioning to accommodate the southeastward motion of eastern margin of the Tibetan Plateau. Integrated analysis of principal strain tensors, mean principal stress, and fast directions of mantle anisotropy shows that west of Sichuan is characterized as mechanically strong crust-mantle coupling.

关键词： GPS measurement Longmenshan faultzone Longriba fault zone tectonic deformation TibetanPlateau