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Two types of changes in apparent resistivity in earthquake prediction

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Science china Earth Sciences 2011年第1期54卷 145-156页

作者： DU XueBin1.2 1.anzhou institute of Seismology,{1., Lanzhou 730000, china 2Lanzhou Base of earthquake Science institute,{1., Lanzhou 730000, china 1. Lanzhou institute of Seismology China Earthquake Administration Lanzhou 730000 China2. Lanzhou Base of Earthquake Science Institute China Earthquake Administration Lanzhou 730000 China

Two types of changes in apparent resistivity (AR) have been linked to earthquake occurrences. This paper studies the changes and their causes, in detail with the ultimate purpose of developing and assessing a method of earthquake (EQ) prediction. The AR changes of the first type (CFT) are considered to be precursors related to earthquakes (EQs); these appear mostly in the medium-term period before EQs and in the short-term period preceding EQs. The changes of the second type (CST) are characterized by a turning anomaly of a long-trend AR variation or the drastically descending/ascending anomaly superimposed on such a variation; these appear synchronously in large areas, such as the Chinese mainland, and northern and northwestern china, ect. Their spatio-temporal clusters correspond well to high seismicities in the areas and distant great EQs around the Chinese mainland. Based on the behaviors of the two types of changes, the AR changes observed prior to the Ms8.0 Wenchuan EQ of 2008 are studied. The results show that in the medium-term period before the EQ, noticeable anomalies appeared synchronously at four stations around the Songpan-Ganzi active block, but only weak upward changes were observed in the short-term period preceding the EQ, which caused the prediction of the imminent EQ to fail.

关键词： strong earthquake apparent resistivity two types of changes spatio-temporal cluster Wenchuan earthquake

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,{1., Beijing 1.0039, china 2 earthquake {4. of Gansu Province, Lanzhou 730000, china institute of Geology China Earthquake Administration Beijing China earthquake {1. 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

Joint exploration of crustal structure in Fuzhou basin and its vicinities by deep seismic reflection and high-resolution refraction as well as wide-angle reflection/refraction

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Science china Earth Sciences 2005年第7期48卷 925-938页

作者： ZHU Jinfang1. XU Xiwei2, ZHANG Xiankang3, HUANG Zonglin1. CHEN Xiangxiong1. FANG Shengming3, LIU Baojin3, ZHENG Rongzhang2,4.1. Seismological Bureau of Fujian Province,Fuzhou 350003,{1. 2. institute of Geology,{1. earthquake {4.,Beijing 1.0029,{1. 3. Research Center for Exploration Geophysics,{1. earthquake {4.,Zhengzhou 4.0002,{1. 4. State Key Laboratory of earthquake Dynamics,institute of Geology,{1. earthquake {4.,Beijing 1.0029,{1. Seismological Bureau of Fujian Province Fuzhou 350003 China institute of Geology China Earthquake Administration Beijing 100029 China Research Center for Exploration Geophysics China Earthquake Administration Zhengzhou 450002 China State Key Laboratory of earthquake Dynamics Institute of Geology China Earthquake Administration Beijing 100029 China

The Fuzhou basin and its vicinities are located at the northern end of the southeastern coastal seismic zone of the mainland of china. By the joint explorations of high-resolution seismic refraction and wide-angle reflection/refraction as well as deep seismic reflection in the region, which is the first synthetic profile in china, its fine velocity structure and geometric structure from the ground to Moho discontinuity is obtained. The result shows that the crust is obviously layered with a thickness of about 32 km. Basically, it consists of two parts: upper crust and lower crust. The velocity of the upper crust is 5.9-6.2 km/s in which there is a 3-4.km-thick weak low-velocity layer between the depths of 1.-1. km, while the velocity of the lower crust in the range of 6.3-7.2 km/s. There exists a strong velocity gradient layer about 3 km thick above the Moho discontinuity whose velocity increases from 6.5 to 7.27 km/s. There exist high-angle normal faults that are small in size and extend only in the shallow crust. These faults are the secondary developed on the hanging wall of westward dipping low-angle normal faults. Thus, their seismogenic ability is limited, however, there exists a high-angle deep fault in the crust from Changle-Zaoan fault zone to seashore fault zone. This deep fault has cut the interface between the upper and lower crusts and Moho discontinuity, and may be the deep structure to trigger destructive earthquake source in future to affect Fuzhou City. These results have advanced the detecting precision of the deep structure in the southeastern coastal seismic zone of the mainland of china. In the aspect of the combined feature of the deep and shallow extensional structures that consist of the westward dipping low-angle normal faults and secondary normal faults on their hanging walls in the upper crust, it is firstly obtained that a united structural interpretation has deepened the knowledge about the deep dynamic process in the southeastern coasta

关键词： deep seismic reflection high-resolution seismic refraction wide-angle.

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 {1. 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 {1.(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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Progress and review of the studies on the end-Triassic mass extinction event

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Science china Earth Sciences 2005年第12期48卷 2049-2060页

作者： DENG Shenghui1.2, LU Yuanzheng1.2,3 & XU Daoyi4.1. Research {1. of Petroleum Exploration and Development, Beijing 1.0083, china 2. Key Laboratory of Oil and Gas Reservoir of Petrochina, Beijing 1.0083, china 3. china University of Geosciences, Beijing 1.0083, china 4. {1. of Geology, china earthquake administration, Beijing 1.0029, china 1. Research institute of Petroleum Exploration and Development 100083 Beijing China 2. Key Laboratory of Oil and Gas Reservoir of Petrochina 100083 Beijing China 3. china University of Geosciences 100083 Beijing China 4. {1. of Geology China Earthquake Administration 100029 Beijing China

The mass extinction at the end-Triassic is one of the five biggest in the Phanerozoic. However,it is the least well understood among these five events, and only till last decade it became a great academic interesting subject to geologists. The evidences for this event come obviously from bivalves, brachiopods, ammonites, corals, radiolaria, ostracods and foraminifera of marine habitats, and plants and tetrapods of terrestrial realm. By contrast, for some of other groups, such as marine gastropods and marine vertebrates, no mass extinction has been recog-nized yet. The extinction event is strongly marked at specific level but shown a complicated situa-tion at generic and family levels. Dramatic changing of the environment, such as the temperature raise due to the greenhouse effect, the marine anoxic habitats caused by a sudden transgression after the regression at the end of Triassic, has been claimed to be the main cause of the extinction. Many hypotheses have been suggested to demonstrate the mechanisms of the environment changing, among which two popular ones are the bolide impact and volcanic eruption. The Triassic-Jurassic (Tr-J) boundary mass extinction event is still poorly understood because no enough data have been obtained from the Tr-J boundary successional sections of both marine and terrestrial sediments, and most of these studies were regionally restricted. The basic aspects of the event and its associated environmental conditions remain poorly characterized and the causal mechanism or mechanisms are equivocal. Some authors even doubt its occurrence. china has many successionally developed terrestrial and marine Tr-J sections. Detailed studies of these sections may be important and significant for well understanding of the event.

关键词： progress, review, end-Triassic, mass extinction, mechanism, Tr-J boundary.

The tectonic settings and seismogenic tectonics of the M5.7 Jiujiang earthquake in 2005,Jiangxi Province,{1.

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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,{1., Beijing 1.0029, china 2 Jiangxi earthquake {4., Nanchang 330039, china 3 Beijing earthquake {4., Beijing 1.0080, china 1. institute of Geology China Earthquake Administration Beijing 100029 China 2. Jiangxi earthquake {1. Nanchang 330039 China 3. Beijing earthquake {1. 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

Distribution and characteristics of gravelly soil liquefaction in the Wenchuan M_s 8.0 earthquake

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earthquake Engineering and Engineering Vibration 2010年第2期9卷 167-175页

作者： Cao Zhenzhong1.Hou Longqing2,Xu Hongmei2 and Yuan Xiaoming1.1. institute of Engineering Mechanics,{1. earthquake administration,Harbin 1.0080,{1. 2. East {1. institute of Technology,Fuzhou 34.000,{1. institute of Engineering Mechanics China Earthquake Administration Harbin 150080 China

In this paper,a distribution map of gravelly soil liquefaction that was caused by the Wenchuan M8.0 earthquake in {1. is proposed based on a detailed field investigation and an analysis of geological soil profiles. The geological background of the earthquake disaster region is summarized by compiling geological cross sections and borehole logs. Meanwhile,four typical liquefied sites were selected to conduct sample drillings,dynamic penetration tests (DPT),and shear wave velocity tests,to understand the features of liquefied gravelly soil. One hundred and eighteen (1.8) liquefied sites were investigated shortly after the earthquake. The field investigation showed:(1. sandboils and waterspouts occurred extensively,involving thousands of miles of farmland,1.0 villages,eight schools and five factories,which caused damage to some rural houses,schools,manufacturing facilities and wells,etc.; (2) the Chengdu plain is covered by a gravelly soil layer with a thickness of 0 m to 54. m according to the geological cross sections; (3) there were 80 gravelly soil liquefied sites in the Chengdu plain,shaped as five belt areas that varied from 20 km to 4. km in length,and about ten gravelly soil liquefied sites distributed within Mianyang area; and (4. the grain sizes of the sampled soil were relative larger than the ejected soil on the ground,thus the type of liquefied soil cannot be determined by the ejected soil. The gravelly soil liquefied sites are helpful in enriching the global database of gravelly soil liquefaction and developing a corresponding evaluation method in further research efforts.

关键词： gravelly soil liquefaction borehole soil profile geological cross section grain size distribution Wenchuan earthquake

The upper mantle structure of the Tibetan Plateau and its implication for the continent-continent collision

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Science china Earth Sciences 2005年第8期48卷 1158-1164页

作者： WU Qingju1. ZENG Rongsheng1.& ZHAO Wenjin2 1. institute of Geophysics,{1., Beijing 1.0081. china 2. institute of Geology, china Academy of Geological Sciences, Beijing 1.0037, china 1. institute of Geophysics China Earthquake Administration 100081 Beijing China 2. institute of Geology China Academy of Geological Sciences 100037 Beijing China

The upper mantle structures of Himalayas-Tibet have been obtained from the mi-gration of receiver functions of the teleseismic events recorded by INDEPTH-III. The result of migration imaging shows a dipping interface subducting northward from the depth of 1.0 km to the 4.0-km discontinuity underneath southern Tibet. It indicates that the lithospheric mantle of the Indian continent had been detached from the crust and deeply subducted to the upper mantle of Eurasia during the Indo-Eurasian collision. This kind of continent-continent collision process is fundamentally different from the oceanic collision.

关键词： Tibetan Plateau, receiver function, upper mantle structures, Indo-Eurasian collision, dipping interface.

Average slip rate, earthquake rupturing segmentation and recurrence behavior on the Litang fault zone, western Sichuan Province, {1.

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Science china Earth Sciences 2005年第8期48卷 1183-1196页

作者： XU Xiwei1. WEN Xueze2, YU Guihua1. ZHENG Rongzhang1. LUO Haiyuan2 & ZHENG Bin2 1. institute of Geology,{1., Beijing 1.0029, china 2. earthquake {4. of Sichuan Province, Chengdu 61.04., china 1. institute of Geology China Earthquake Administration 100029 Beijing China 2. earthquake {1. of Sichuan Province 610041 Chengdu China

The Litang fault zone (LFZ) is an active fault zone within the northwestern Sichuan sub-block. Field investigation reveals new evidence for its late Quaternary offset, neoteric earthquake ruptures and surface-rupturing segmentation, from which long-term slip-rates, char-acteristic earthquake magnitudes and recurrence intervals on the fault zone are estimated. This study shows that the LFZ consists of three subordinate faults, and they are the northern Maoyaba fault, Litang fault and Kangga-Dewu fault, respectively. All of them are dominated by left-lateral strike-slip with reverse dip-slip component on different segments. Based on offset landforms and ages of relevant deposits collected from seven sites, it is estimated that the average left-lateral slip-rate on the LFZ reaches 4.0±1.0 mm/a in the past 1.2}ka BP, and vertical (reverse) dip-slip rate in the range of 0.1.1.8 mm/a. Three subordinate faults are independent earthquake rup-turing segments, on which the maximum moment magnitude of the characteristic earthquakes is estimated to be 7.0―7.3, and their average recurrence interval to be 500―1.00 a. The latest earthquake ruptures occurred 1.9±2 years ago on the northern Maoyaba fault, about 1.90 AD on the Litang fault, and in 1.4. AD on the Kangga-Dewu fault, and this may indicate a unidirectional migration for surface rupturing earthquakes along the Litang fault zone, related to stress trigger-ing between the segments.

关键词： Litang fault zone, slip rate, earthquake rupturing segmentation, recurrence interval.