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The deformation pattern and fault rate in the Tianshan Mountains inferred from GPS observations

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Science china Earth Sciences 2008年第8期51卷 1064-1080页

作者： YANG ShaoMin1,2, LI Jie1,3 & WANG Qi2,1 1 Research Center of Space Science and Technology, china University of Geosciences, wuhan 430074, china 2.institute of seismology, china earthquake administration, wuhan 430071, china 3 earthquake administration of Xinjiang Uygur Autonomous Region, Urumqi 830011, china 1. Research Center of Space Science and Technology China University of Geosciences Wuhan 430074 China 2. institute of seismology China Earthquake Administration Wuhan 430071 China 3. earthquake administration of Xinjiang Uygur Autonomous Region Urumqi 830011 China

Based on GPS measurements conducted from 1992 to 2006, we present the current crustal movement velocity field for approximately 400 sites in the Tianshan Mountains and their adjacent areas, and estimate slip rates on the major faults using a 2-D elastic dislocation model. Our studies show slip rates within the range of 1―4 mm/a on the NW-SE trending strike-slip faults (such as Talas-Fergana fault) in the Tianshan Mountains. We also found the slip rates on the approximately WE-SN trending gently-dipping detachment fault vary from 10―13 mm/a for the southwest Tianshan Mountains to 2―5 mm/a for the eastern Tianshan Mountains, and to 6―12 mm/a for the Kyrgrz Tianshan. The GPS velocity field reveals that the total convergence is not uniformly distributed across the Tianshan Mountains, with 80%―90% of the N-S shortening absorbed along the southern and northern edges, and relatively little deformation accommodated within the interior. This first-order feature of strain pattern is explained best by underthrusting of adjacent blocks beneath the Tianshan Mountains along a basal detachment fault. We found the occurrence of historical M7―8 earthquakes somewhere in the locked ramp that connects the creeping and locking segments of the detachment, thereby resulting in elastic strain concentration and accumulation around it. The elastic strain confined in the upper crustal layer above the detachment ultimately releases through infrequent great earthquakes in the Tianshan Mountains, resulting in considerable folding and faulting at their margins. The Tianshan Mountains propagated outward and rose progressively as a wedge-shaped block.

关键词： Tianshan Mountains GPS slip rates tectonic deformation

Discussion on moment tensor solution and seismogenic structure of Ruichang-Yangxin earthquake on 10 September 2011

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earthquake Science 2012年第3期25卷 229-234页

作者： Lifen Zhang1,2, Guichun Wei and Wulin Liao1 1 Key Laboratory of earthquake Geodesy, institute of seismology, china earthquake administration, wuhan 430071, china 2.institute of Geophysics, china earthquake administration, Beijing 100081, china 1. Key Laboratory of earthquake Geodesy Institute of Seismology China Earthquake Administration Wuhan 430071 China 2. institute of Geophysics China Earthquake Administration Beijing 100081 China

Ruichang-Yangxin earthquake is another moderate earthquake in Yangxin-Jiujiang area since 2005 Jiujiang-Ruichang M5.7 earthquake. In order to more understand the seismic activities in this area, we study the moment tensor solution and the seismogenic structure of the Ruichang-Yangxin earthquake. Precise earthquake relocation shows that the mainshock occurred on the southwestern part of the NE-trending fault and aftershocks are distributed not only along the NE-trending fault but also along its conjugated NW-trending fault. By comprehensive analysis on the earthquake distribution, characteristics of isoseismal curve, focal mechanism, and regional structure characteristics, it is inferred that this earthquake is caused by the NE-trending Tanlu fault. In addition, it has close relationship with the conjugated NW-trending fault as well. Many researches have shown that the junction area is the earthquake-prone area, and should be paid more attention to. And our study also proves this viewpoint.

关键词： moment tensor inversion Ruichang-Yangxin earthquake seismogenic structure

Serving High-Level Opening up with "TaxExpress"

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Belt and Road Initiative Tax Journal 2024年第1期 97-105页

作者： International Taxation Department, State Taxation administration,the People's Republic of china International Taxation Department State Taxation Administrationthe People's Republic of China

Over the past decade,the Chinese tax authorities have been actively supporting the development of the Belt and Road Initiative,by creating a unique cross-border tax and fee service model with Chinese characteristics,which has laid a solid foundation for the establishment of the "TaxExpress" cross-border service *** October 2023,the State Taxation administration of china(STA) officially launched the "TaxExpress" brand,focusing on one service matrix,two service teams,three service mechanisms,and four knowledge *** brand aims to enhance cooperation between ministries and commissions,promote international exchanges,and establish a framework for effective cross-border tax and fee *** forward,the STA will continue to leverage existing resources to support high-level opening up,by enhancing brand value,improving measures for international tax and fee services,expanding cross-border tax and fee services,strengthening professional talent teams,so as to develop a cross-border tax and fee service system that combines Chinese characteristics with international best practices.

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Prilimary result of temperature distribution and associated thermal stress in crust in Tianshui, china

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Acta Seismologica Sinica(English Edition) 2007年第6期20卷 641-655页

作者：刘耀炜高安泰Lanzhou institute of seismology china earthquake administration 施锦Lanzhou institute of seismology china earthquake administration 苏鹤军Lanzhou institute of seismology china earthquake administration School of Water Resources and Environment China University of Geosciences

The heat flow in crust and the thermal stress generated by the flow play a very important role in earthquake occurrence. Different crustal structure has different effect on heat distribution and associated thermal stress. In all of typical seismogenic crustal structure models, including the bulge of Moho surface, the deep-large fault in the mid-lower crust, low-velocity and high-conductive layer in the middle crust, and the typical crustal structure in mid-upper crust, the thermal stress produced by deep heat disturbance may move up to the mid-upper crest. This leads to upper brittle part of crust break and hence, strong earthquakes. This result is constructive in enhancing our understanding of the role of deep fieat flow in curst in development of earthquake and its generation, as well as the generation mechanism of the shallow flowing fluid.

关键词： earthquake crust structure thermal stress numerical simulation geothermal field

Plumb line variation at Tangshan during 1987―1998 and its relation with the earthquakes around

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Science china Earth Sciences 2009年第1期52卷 101-107页

作者： LI ZhengXin1,2 & LI Hui3 1 Shanghai Observatory,Chinese Academy of Sciences,Shanghai 200030,china 2.institute of Geodesy and Geophysics,Chinese Academy of Sciences,Wuchang 430077,china 3 institute of seismology,china earthquake administration,Wuchang 430071,china Shanghai Observatory Chinese Academy of Sciences Shanghai 200030 China institute of Geodesy and Geophysics Chinese Academy of Sciences Wuchang 430077 China institute of seismology China Earthquake Administration Wuchang 430071 Chin

Plumb line variations(PLV) at Tangshan during the years of 1987―1998 are determined by using the 46 batch repeated gravity observations of the Beijing-Tangshan *** has been found that PLV at Tangshan are related with the 38 earthquakes in this *** appears that the time of an earthquake around Tangshan is usually quite the same when PLV at Tangshan begins moving in opposite direction.

关键词： plumb line variations network in northern china variations of local gravity field earthquakes

Evolution of terraces Ⅰ–Ⅲ along the Anning River, western Sichuan, based on pollen records and terrace structure

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Science china Earth Sciences 2011年第1期54卷 127-135页

作者： CHENG JianWu1,2 1 institute of Geology, china earthquake administration, Beijing 100039, china 2 earthquake administration of Gansu Province, Lanzhou 730000, china institute of Geology China Earthquake Administration Beijing China earthquake administration of Gansu Province Lanzhou China

This study reconstructs the long-term evolution of river terraces over large spatial scales along the Anning River, western Sichuan, and identifies external factors controlling terrace formation. Pollen record analysis and terrace structure indicate that formation of the middle section of terraces I-III resulted from the interaction of changing climates and uplift of the margins of the Qinghai-Tibet Plateau. The relative influence of climate and uplift in terrace formation changes in different periods. The terraces reveal multiple, gradual uplift events on the eastern Qinghai-Tibet Plateau, which is of great significance for determining uplift mechanisms across the entire plateau.

关键词： Anning River in western Sichuan terrace formation pollen paleoclimate

The tectonic settings and seismogenic tectonics of the M5.7 Jiujiang earthquake in 2005,Jiangxi Province,china

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Science china Earth Sciences 2008年第5期51卷 640-653页

作者： LI ChuanYou1, ZENG XinFu2 & ZHANG JianXi3 1 institute of Geology, china earthquake administration, Beijing 100029, china 2 Jiangxi earthquake administration, Nanchang 330039, china 3 Beijing earthquake administration, Beijing 100080, china 1. institute of Geology China Earthquake Administration Beijing 100029 China 2. Jiangxi earthquake administration Nanchang 330039 China 3. Beijing earthquake administration Beijing 100080 China

The M5.7 Jiujiang earthquake in 2005 was a mid-strong one, stronger than expected to occur in the region. This paper discusses the neo-tectonic settings of this earthquake, and it is thought that the earthquake region is located in the transitional belt, a potential area inducing weak to moderately strong earthquakes, between two large different tectonic units. The results of the reconnaissance work and on-the-spot investigation after earthquake indicate that the occurrence of the M5.7 Jiujiang earth- quake is closely related with the NE-trending fault on the western margin of Ruichang Basin. From its controlling to the landforms and Quaternary depositions, geological profiles, ESR dating, etc., the ac- tivity of the Dingjiashan-Langjunshan fault bounding the basin is discussed. It suggests that this fault displays an active one in Middle Pleistocene by the outcrop. Based on the activity of the fault, and the direction and location of the ground fissures, the isoseismal lines and the nodal plane of the focal mechanism solution, it is inferred that the Dingjiashan-Langjunshan fault is the seismogenic tectonics of the M5.7 Jiujiang earthquake, and the intersection point between this fault and the active NW ones is the possible origin of location of this earthquake. Our study shows that this earthquake is not an event exceeding expectation, and that the active and invisible characteristics of the causative fault are typical in the eastern area of china.

关键词： Jiujiang earthquake tectonic settings Dingjiashan-Langjunshan fault activity seismogenic tectonics

A circum-earth shear zone at low-latitudes and episodic large earthquakes in it and the circum-Pacific seismic zone

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Science china Earth Sciences 2006年第9期49卷 897-903页

作者： MA Zongjin1, DU Pinren1, REN Jinwei2 & GAO Xianglin1 1. institute of Geology, china earthquake administration, Beijing 100029, china 2. institute of earthquake Science, china earthquake administration, Beijing 100036, china 1. institute of Geology China Earthquake Administration Beijing 100029 China 2. institute of earthquake Science China Earthquake Administration Beijing 100036 China

Because of the differential motions between the Northern and Southern Hemispheres of the Earth, there exists a motion discordant zone between them. On the surface this zone consists of 13 large faults dominant with strike-slip. We call it a global shear zone at low-latitudes (E system). By statistical analysis of temporal distribution of earthquakes Mw≥7.5 in the E system and the circum-Pacific (P system) during 1900―2003, we find that there exist quasi-episodic and alternative activities in and between these two systems. This phenomenon is likely associated with the half-sphere oscillation in dilation and contraction and the change of the Earth’s rotation rate.

关键词： shear zone, circum-Pacific zone, great earthquake, quasi-episode.

Source mechanism of strong aftershocks (M_s≥5.6) of the 2008/05/12 Wenchuan earthquake and the implication for seismotectonics

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Science china Earth Sciences 2009年第6期52卷 739-753页

作者： ZHENG Yong1,2,MA HongSheng3,Lü Jian4,NI SiDao5,LI YingChun6 & WEI ShengJi2 1 institute of Geodesy and Geophysics,Chinese Academy of Sciences,wuhan 430077,china 2.institute of Geophysics,Chinese earthquake administration,Beijing 100086,china 3 institute of earthquake Science,Chinese earthquake administration,Beijing 100086,china 4 earthquake administration of Jiangxi Province,Nanchang 330039,china 5 School of Earth and Space Science,University of Science and Technology of china,Hefei 230026,china 6 earthquake administration of Jiangsu Province,Nanjing 210014,china 1. institute of Geodesy and Geophysics Chinese Academy of Sciences Wuhan 430077 China 2. institute of Geophysics Chinese Earthquake Administration Beijing 100086 China 3. institute of earthquake Science Chinese Earthquake Administration Beijing 100086 China 4. earthquake administration of Jiangxi Province Nanchang 330039 China 5. School of Earth and Space Science University of Science and Technology of China Hefei 230026 China 6. earthquake administration of Jiangsu Province Nanjing 210014 China

Dozens of >M5, hundreds of >M4, and much more >M3 aftershocks occurred after the 2008/05/12 Wenchuan earthquake, which were well recorded by permanent and portable seismic stations. After relocated with P arrival, the >M3 aftershocks show two trends of distribution, with most of the aftershocks located along the north-east strike consistent with Longmenshan fault system, yet there is a north-west trend around the epicenter. It seems that substantially more aftershocks occur in regions with crystalline bedrocks. Then we collected waveform data from National Digital Seismograph Network and regional seismograph network of china, and employed 'Cut and Paste' method to obtain focal mechanisms and depths of the big aftershocks (M≥5.6). While most of those aftershocks show thrust mechanism, there are some strike slip earthquakes in the northern-most end of the rupture. Focal mechanisms show that the events located on the southern part of central Beichuan-Yingxiu Fault (BY) are mainly thrust earthquakes, which is consistent with initial mechanism of the main shock rupture. In the north part the aftershocks along the BY are also dominated by thrust slip, which is quite different from the right slip rupture of the main shock. Around Qingchuan-Pingwu Fault, the focal mechanisms are dominated by right-slip rupture with large depths (~18 km). So we suspected that in the north part the main shock might rupture on two faults: Beichuan Fault and Qingchuan-Pingwu Fault. The complex pattern of aftershock mechanisms argues for presence of a complicated fault system in the Longmenshan area.

关键词： focal mechanism seismotectonics Wenchuan earthquake cut and paste.