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Rock Damage Structure of the South Longmen-Shan Fault in the 2008 M8 Wenchuan Earthquake Viewed with Fault-Zone Trapped Waves and Scientific Drilling 被引量:9
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作者 LI Yonggang XU Zhiqin LI Haibing 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2014年第2期444-467,共24页
This article is to review results from scientific drilling and fault-zone trapped waves (FZTWs) at the south Longman-Shan fault (LSF) zone that ruptured in the 2008 May 12 M8 Wenchuan earthquake in Sichuan,China.I... This article is to review results from scientific drilling and fault-zone trapped waves (FZTWs) at the south Longman-Shan fault (LSF) zone that ruptured in the 2008 May 12 M8 Wenchuan earthquake in Sichuan,China.Immediately after the mainshock,two Wenchuan Fault Scientific Drilling (WFSD) boreholes were drilled at WFSD-1 and WFSD-2 sites approximately 400 m and 1 km west of the surface rupture along the Yinxiu-Beichuan fault (YBF),the middle fault strand of the south LSF zone.Two boreholes met the principal slip of Wenchuan earthquake along the YBF at depths of 589-m and 1230-m,respectively.The slip is accompanied with a 100-200-m-wide zone consisting of fault gouge,breccia,cataclasite and fractures.Close to WFSD-1 site,the nearly-vertical slip of ~4.3-m with a 190-m wide zone of highly fractured rocks restricted to the hanging wall of the YBF was found at the ground surface after the Wenchuan earthquake.A dense linear seismic array was deployed across the surface rupture at this venue to record FZTWs generated by aftershocks.Observations and 3-D finite-difference simulations of FZTWs recorded at this cross-fault array and network stations close to the YBF show a distinct low-velocity zone composed by severely damaged rocks along the south LSF at seismogenic depths.The zone is several hundred meters wide along the principal slip,within which seismic velocities are reduced by ~30-55% from wall-rock velocities and with the maximum velocity reduction in the ~200-m-wide rupture core zone at shallow depth.The FZTW-inferred geometry and physical properties of the south LSF rupture zone at shallow depth are in general consistent with the results from petrological and structural analyses of cores and well log at WFSD boreholes.We interpret this remarkable low-velocity zone as being a break-down zone during dynamic rupture in the 2008 M8 earthquake.We examined the FZTWS generated by similar earthquakes before and after the 2008 mainshock and observed that seismic velocities within fault core zone was reduced by ~10% due to severe damage of fault rocks during the M8 mainshock.Scientific drilling and locations of aftershocks generating prominent FZTWs also indicate rupture bifurcation along the YBF and the Anxian-Guangxian fault (AGF),two strands of the south LSF at shallow depth.A combination of seismic,petrologic and geologic study at the south LSF leads to further understand the relationship between the fault-zone structure and rupture dynamics,and the amplification of ground shaking strength along the low-velocity fault zone due to its waveguide effect. 展开更多
关键词 Rupture zone rock damage structure scientific drilling fault-zone trapped waves Wenchuan Earthquake longmen-Shan fault
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Late Quaternary Activity of the Central-North Segment of the Taihang Mountains Piedmont Fault Zone
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作者 Gao Zhanwu Wu Hao +1 位作者 Li Gangtao Cheng Li 《Earthquake Research in China》 CSCD 2015年第1期103-116,共14页
The location and late Quaternary activity of the Central-North Segment of the Taihang Mountains Piedmont fault zone have been studied by shallow seismic survey and combined drill exploration.Our results show that the ... The location and late Quaternary activity of the Central-North Segment of the Taihang Mountains Piedmont fault zone have been studied by shallow seismic survey and combined drill exploration.Our results show that the Baoding-Shijiazhuang fault and the Xushui fault were active in the late Pleistocene,but the south Xushui fault has been inactive since the late Pleistocene.The maximum magnitude of potential earthquake of the faults is 6.0. 展开更多
关键词 Taihang mountains Piedmont fault zone Activity in late QuaternaryShallow seismic survey Combined drill exploration
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Tectonic implication of geomorphometric analyses along the Saravan Fault: evidence of a difference in tectonic movements between the Sistan Suture Zone and Makran Mountain Belt 被引量:1
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作者 Roghayeh KASHANI Abdolreza PARTABIAN Ahmad NOURBAKHSH 《Journal of Mountain Science》 SCIE CSCD 2019年第5期1023-1034,共12页
In this paper, remote sensing techniques,as well as field studies, have been used to investigate the geomorphological processes and landscape evolution along the Saravan Fault, SE Iran to highlight how topographic fea... In this paper, remote sensing techniques,as well as field studies, have been used to investigate the geomorphological processes and landscape evolution along the Saravan Fault, SE Iran to highlight how topographic features were influenced by active tectonics. Quantitative geomorphic analysis was carried out using mountain-front sinuosity(Smf),valley floor width-valley height ratio(Vf), drainage basin asymmetry factor(Af), Hypsometric integral(Hi), drainage basin shape index(Bs), mean axial slope of channel(MASC), standard deviation of topography(STD) and index of active tectonic(Iat).Remote sensing techniques, as well as field studies revealed that the Saravan Fault have three parts trending N-S, NW-SE, and E-W. Obtained results show that basins with high Iat index are located at where the strike of the Saravan Faults changes and where several strike-slip faults are crossed the Saravan fault. 展开更多
关键词 Active TECTONIC Sistan SUTURE zone MAKRAN MOUNTAIN BELT Saravan fault Iran DEM
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RELATIONSHIP BETWEEN P-T CONTITIONS OF TWO PHASES OF TAN-LU STRIKE-SLIP SHEAR ZONES AND DELAMINATION OF OROGENIC BELTS ON THE EASTERN MARGIN OF THE DABIE MOUNTAINS 被引量:2
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作者 WANG Yongsheng ZHU Guang WANG Daoxuan LIU Guosheng SONG Chuanzhong 《Geotectonica et Metallogenia》 2005年第2期139-151,共13页
The Tan-Lu fault zone joins the Dabie Mountains on its eastern margin, and offsets the Dabie and Sulu orogenic belts sinistrally for about 500 kin. On the basis of calculation of temperature and pressure experienced b... The Tan-Lu fault zone joins the Dabie Mountains on its eastern margin, and offsets the Dabie and Sulu orogenic belts sinistrally for about 500 kin. On the basis of calculation of temperature and pressure experienced by the two phases of the fault zone as well as the thermo-chronological information on mylonite from the earlier and later Tan-Lu fault zones on the eastern margin of the Dabie Mountains, this paper discusses the delamination history and uplifting magnitudes of the Dabie Mountains from earlier Jurassic to earlier Cretaceous. From mineral assemblages, mineral deformation and muscovite-chlorite geothermometry calculation, it is known that the temperature experienced by the two phases of Tan-Lu fault zones are between 40℃ and 450℃, and the confining pressures are between 0.25Gpa and 0.36GPa for the earlier shear zones and 0.24-0.39GPa for the late shear zones. According to the geobarometry of Si-in-phengite and by considering shear heating and tectonic over-pressure, it is concluded that the maximum formation depths for the two phases of the ductile shear zones are not more than 12 kin. Differential formation depths for the two phases of shear zones are 1-2 km at most. At about 190 Ma and 128 Ma, the Tan-Lu fault zone experienced two phases of cooling events. During this period, the eastem margin of the Dabie Mountains experienced a tectonic calm period and no uplifting. According to information from the Tan-Lu fault zone, the uplifting magnitudes of the Dabie orogenic belts are not more than 12 km during the earlier Cretaceous. 展开更多
关键词 eastern margin of DaNe mountains Tan-Lu fault zone orogenic delamination PHENGITE thermometry
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DEFORMATIONAL AND METAMORPHIC HISTORY OF THE CENTRAL LONGMEN MOUNTAINS, SICHUAN CHINA
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作者 Chris J.L. Wilson 1, Brenton A. Worley 1, Shefa Chen 1, Mathew J. Harrowfield 1,Liu Shugen 2,Luo Zhili 2 2 Chengdu University of Technology, Chengdu 6 《地学前缘》 EI CAS CSCD 2000年第S1期273-274,共2页
The Longmen Mountains and adjacent regions on the eastern margin of the Tibetan plateau can be divided into three tectonic units: the eastern Songpan—Garzê fold belt, the Longmen Mountains (Longmen Shan) Thrust... The Longmen Mountains and adjacent regions on the eastern margin of the Tibetan plateau can be divided into three tectonic units: the eastern Songpan—Garzê fold belt, the Longmen Mountains (Longmen Shan) Thrust—Nappe belt and the Western Sichuan foreland basin that occupies the western part of the Sichuan basin. The Longmen Shan Thrust—Nappe belt is subdivided by six northwest\|dipping major listric thrusts, with accompanying duplexes and imbricate fans, into five large\|scale nappes (Chen & Wilson, 1996). In the inner Longmen Shan, the nappe units have incorporated both Mesoproterozoic basement and Sinian (Neoproterozoic) to Triassic cover sequences as “thick\|skinned" horses. Whereas, in the frontal Longmen Shan, Sinian to Cretaceous cover sediments have been stripped from the basement as “thin\|skinned" fold and thrust sheets, including extensively distributed klippen structures. Pre\|thrusting extension during Devonian to middle Late Triassic times resulted in syndepositional normal faults. Structural inversion of these faults initiated the “Peng Xian—Guan Xian basement complex", Jiuding Shan and Tangwangzhai nappes, during an early episode of the Indosinian Orogeny (Norian to Rhaetian). This was followed by episodic thrusting during latest Triassic to Early Cretaceous times to develop the Guan Xian—An Xian and Southeastern Marginal nappes that have incorporated sediments from the neighbouring foreland basin into the frontal part of the Thrust—Nappe belt. Differential thrusting occurred across the Thrust—Nappe belt during a Late Miocene reactivation of the pre\|existing faults. 展开更多
关键词 longmen mountains Songpan—Garzê fold BELT Wenchuan—Mouwen SHEAR zone Wenchuan—Mouwen fault METAMORPHIC BELT transpressional SHEAR Himalayan OROGENY Indosinian OROGENY
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Study on rupture zone of the M=8.1 Kunlun Mountain earthquake using fault-zone trapped waves
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作者 李松林 张先康 樊计昌 《Acta Seismologica Sinica(English Edition)》 EI CSCD 2005年第1期43-52,共10页
The observation of the fault-zone trapped waves was conducted using a seismic line with dense receivers across surface rupture zone of the M=8.1 Kunlun Mountain earthquake. The fault zone trapped waves were separated ... The observation of the fault-zone trapped waves was conducted using a seismic line with dense receivers across surface rupture zone of the M=8.1 Kunlun Mountain earthquake. The fault zone trapped waves were separated from seismograms by numerical filtering and spectral analyzing. The results show that: a) Both explosion and earthquake sources can excite fault-zone trapped waves, as long as they locate in or near the fault zone; b) Most energy of the fault-zone trapped waves concentrates in the fault zone and the amplitudes strongly decay with the distance from observation point to the fault zone; c) Dominant frequencies of the fault-zone trapped waves are related to the width of the fault zone and the velocity of the media in it. The wider the fault zone or the lower the velocity is, the lower the dominant frequencies are; d) For fault zone trapped waves, there exist dispersions; e) Based on the fault zone trapped waves observed in Kunlun Mountain Pass region, the width of the rupture plane is deduced to be about 300 m and is greater than that on the surface. 展开更多
关键词 fault-zone trapped waves M=8.1 Kunlun Mountain earthquake seismic rupture plane
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Differential Tectonic Deformation of the Longmen Mountain Thrust Belt,Western Sichuan Basin,China 被引量:6
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作者 TANG Liangjie YANG Keming +3 位作者 JIN Wenzheng WAN Guimei LüZhizhou YU Yixin 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2009年第1期158-169,共12页
Field investigation and seismic section explanation showed that the Longmen Mountain Thrust Belt has obvious differential deformation: zonation, segmentation and stratification. Zonation means that, from NW to NE, th... Field investigation and seismic section explanation showed that the Longmen Mountain Thrust Belt has obvious differential deformation: zonation, segmentation and stratification. Zonation means that, from NW to NE, the Longmen Mountain Thrust Belt can be divided into the Songpan- Garz~ Tectonic Belt, ductile deformation belt, base involved thrust belt, frontal fold-thrust belt, and foreland depression. Segmentation means that it can be divided into five segments from north to south: the northern segment, the Anxian Transfer Zone, the center segment, the Guanxian Transfer Zone and the southern segment. Stratification means that the detachment layers partition the structural styles in profile. The detachment layers in the Longmen Mountain Thrust Belt can be classified into three categories: the deep-level detachment layers, including the crust-mantle system detachment layer, intracrustal detachment layer, and Presinian system basal detachment layer; the middle-level detachment layers, including Cambrian-Ordovician detachment layer, Silurian detachment layer, etc.; and shallow-level detachment layers, including Upper Triassic Xujiahe Formation detachment layer and the Jurassic detachment layers. The multi-level detachment layers have a very important effect on the shaping and evolution of Longmen Mountain Thrust Belt. 展开更多
关键词 differential deformation detachment layer segmentation STRATIFICATION transfer zone zonation longmen Mountain Thrust Belt
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An Experimental Study on the Observation Method of Hydrogen Concentration in Fault Gas
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作者 Fan Xuefang Li Zihong +3 位作者 Li Bin Liu Guojun Huang Chunling Wang Xiangyang 《Earthquake Research in China》 2014年第3期335-349,共15页
In order to explore the new technology and methods for seismic underground fluid observation,a test study on measurement of hydrogen concentration in fault gas is carried out at the piedmont fault zone of Zhongtiao Mo... In order to explore the new technology and methods for seismic underground fluid observation,a test study on measurement of hydrogen concentration in fault gas is carried out at the piedmont fault zone of Zhongtiao Mountain. Through the experiment on observation positions,gas collection devices and sampling depths,the paper presents the observation method for fault gas hydrogen concentration by using an online automatic trace hydrogen analyzer. Comparative tests are conducted on the stability and optimum conditions of this type of instrument in the field environment, and the hydrogen concentrations at different measuring points of the same fault are observed. The results show that it is technically feasible to carry out continuous hydrogen concentration on a fault zone. The method proposed in this study could be a useful tool for setting the observation points,choosing a reasonable observation depth and scientific analysis of the observed data. 展开更多
关键词 the piedmont fault zone of Zhongtiao Mountain fault gas theconcentration of hydrogen Continuous observation New technique forseismic monitoring
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Study on the Development of Earthquake Tourism Resources in Sichuan Province
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作者 傅广海 《Journal of Landscape Research》 2009年第1期32-36,65,共6页
The concept of earthquake tourism resources was defined.With the view of disaster economics,the theory of to tourism plan and the systematic methods,the earthquake tourism resources produced by '5.12' Wenchuan... The concept of earthquake tourism resources was defined.With the view of disaster economics,the theory of to tourism plan and the systematic methods,the earthquake tourism resources produced by '5.12' Wenchuan earthquake were analyzed.The developmental principles and general ideas of the earthquake tourism resources were put forward.The framing proposals were provided on complementation,coordination and integration about the development of the earthquake tourism products in the whole fault zone of Longmen Mountain. 展开更多
关键词 EARTHQUAKE TOURISM RESOURCES Development of EARTHQUAKE TOURISM products fault zone of longmen MOUNTAIN SICHUAN PROVINCE
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Seismogenic Structure around the Epicenter of the May 12,2008 Wenchuan Earthquake from Micro-seismic Tomography 被引量:7
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作者 AN Meijian FENG Mei +5 位作者 DONG Shuwen LONG Changxing ZHAO Yue YANG Nong ZHAO Wenjin ZHANG Jizhong 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2009年第4期724-732,共9页
A three-dimensional local-scale P-velocity model down to 25 km depth around the main shock epicenter region was constructed using 83821 event-to-receiver seismic rays from 5856 aftershocks recorded by a newly deployed... A three-dimensional local-scale P-velocity model down to 25 km depth around the main shock epicenter region was constructed using 83821 event-to-receiver seismic rays from 5856 aftershocks recorded by a newly deployed temporary seismic network. Checkerboard tests show that our tomographic model has lateral and vertical resolution of -2 km. The high-resolution P-velocity model revealed interesting structures in the seismogenic layer: (1) The Guanxian-Anxian fault, Yingxiu-Beichuan fault and Wenchuan-Maoxian fault of the Longmen Shan fault zone are well delineated by sharp upper crustal velocity changes; (2) The Pengguan massif has generally higher velocity than its surrounding areas, and may extend down to at least -10 km from the surface; (3) A sharp lateral velocity variation beneath the Wenchuan-Maoxian fault may indicate that the Pengguan massif's western boundary and/or the Wenchuan-Maoxian fault is vertical, and the hypocenter of the Wenchuan earthquake possibly located at the conjunction point of the NW dipping Yingxiu-Beichuan and Guanxian-Anxian faults, and vertical Wenchuan-Maoxian fault; (4) Vicinity along the Yingxiu- Beichuan fault is characterized by very low velocity and low seismicity at shallow depths, possibly due to high content of porosity and fractures; (5) Two blocks of low-velocity anomaly are respectively imaged in the hanging wall and foot wall of the Guanxian-Anxian fault with a -7 km offset with -5 km vertical component. 展开更多
关键词 Wenchuan earthquake seismogenic structure micro-seismic tomography Pengguan massif longmen Shan fault zone
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The Seismogenic Structure of the 2010 Suining Ms 5.0 Earthquake and its Geometry,Kinematics and Dynamics Analysis 被引量:6
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作者 LU Renqi HE Dengfa +4 位作者 JOHN Suppe MA Yongsheng GUAN Shuwei SUN Yanpeng GAO Jinwei 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2011年第6期1277-1285,共9页
In January 2010, the Suining Ms5.0 earthquake occurred in central Sichuan Basin, with the epicenter in Moxi-Longnvsi structural belt and a focal depth of 10 km. Based on structural interpretations of seismic profiles ... In January 2010, the Suining Ms5.0 earthquake occurred in central Sichuan Basin, with the epicenter in Moxi-Longnvsi structural belt and a focal depth of 10 km. Based on structural interpretations of seismic profiles in this area, we recognized a regional detachment fault located at a depth of 9-10 km in the Presinian basement of the Suining area, transferring its slipping from NW to SE orientation. This detachment fault slipped from NW to SE, and underwent several shears and bends, which caused the basement to be rolled in and the overlaying strata fold deformation. It formed a fault-bend fold in the Moxi area with an approximate slip of 4 km. Correspondingly, the formation of the Moxi anticline is related to the detachment fault. With the earthquake's epicenter on the ramp of the detachment fault, there is a new point of view that the Suining earthquake was caused by re-activation of this basement detachment fault. Since the Late Jurassic period, under the influence of regional tectonic stress, the detachment fault transfered its slip from the Longmen Mountains (LMS) thrust belt to the hinterland of the Sichuan Basin, and finally to the piedmont zone of southwest Huayingshan (HYS), which indicates that HYS might be the final front area of the LMS thrust belt. 展开更多
关键词 Suining Ms5.0 earthquake Seismic interpretation Detachment fault Moxi anticline longmen mountains Sichuan Basin
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Sedimentary characteristics and main controlling factors of the Middle-Upper Permian and Middle-Upper Triassic around Bogda Mountain of Xinjiang,NW China 被引量:2
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作者 YANG Youxing ZHANG Junfeng +5 位作者 ZHANG Jinhu GAO Yongjin ZHOU Xingui SUN Xiangcan WEN Lei MIAO Miaoqing 《Petroleum Exploration and Development》 CSCD 2022年第4期770-784,共15页
Based on field geological survey,interpretation of seismic data and analysis of drilling and logging data,the evolution of geological structures,stratigraphic sedimentary filling sequence and sedimentary system around... Based on field geological survey,interpretation of seismic data and analysis of drilling and logging data,the evolution of geological structures,stratigraphic sedimentary filling sequence and sedimentary system around the Bogda Mountain were analyzed according to the idea of"structure controlling basin,basin controlling facies and facies controlling assemblages".The tectonic evolution of the basin around the Bogda Mountain can be divided into nine stages.The Middle-Late Permian–Middle-Late Triassic was the development stage of intracontinental rift,foreland basin and inland depression basin when lake,fan delta and braided river delta sedimentary facies developed.Early intracontinental rifting,late Permian tectonic uplift,and middle-late Triassic tectonic subsidence controlled the shape,type,subsidence rate and sedimentary system evolution of the basin.The Bogda Mountain area was the subsidence center and deposition center of the deep water lake basin in the Middle Permian with mainly deep-water deposition and local gravity flow deposition.This area had tectonic inversion in the Late Permian,when the Bogda Mountain uplifted to form a low bulge and a series of fan delta sand bodies.In the Middle-Late Triassic,subsidence occurred in the Bogda low uplift,characterized by extensive development of braided river delta deposits. 展开更多
关键词 Junggar Basin Bogda Mountain Fukang fault zone PERMIAN Lucaogou Formation TRIASSIC sedimentary filling sequence sedimentary system
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Regional fault deformation characteristics before and after the Menyuan Ms6.4 earthquake
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作者 Ning Li Lingyun Ji Shuangxu Wang 《Geodesy and Geodynamics》 2016年第4期245-252,共8页
This study analyzes data regarding cross-fault deformations within the seismogenic zone of the 2016 Qinghai Menyuan Ms6.4 earthquake and its surrounding area. The results showed that the tendency anomaly sites near th... This study analyzes data regarding cross-fault deformations within the seismogenic zone of the 2016 Qinghai Menyuan Ms6.4 earthquake and its surrounding area. The results showed that the tendency anomaly sites near the epicenter had relatively long anomaly durations prior to the earthquake, while sudden-jumping anomaly sites started to increase in the middle eastern Qilian Mountains approximately a year before the earthquake and continued to increase and migrate towards the vicinity of the epicenter two to six months before the earthquake. Intensive observations a few days after the earthquake indicated that abnormal returns and turns before the earthquake were significant, but all had small amplitudes, and the coseismic effect was generally minor. In addition, the post-seismic tendency analysis of individual cross faults in the Qilian Mountain fault zone revealed an accelerating thrust tendency at all cross-fault sites in the middle Qilian Mountains after the 2008 Wenchuan Ms8.0 earthquake. This indicates that the Wenchuan mega-earthquake exerted a great impact on the dynamic environment of the northeastern margin of the Qinghai-Tibet plate and significantly enhanced the extrusion effect of the Indian plate on the middle Qilian Mountains, generating favorable conditions for the occurrence of Menyuan thrust earthquakes. 展开更多
关键词 Menyuan Ms6.4 earthquake Cross-fault level Deformation anomaly Tendency anomaly Qilian Mountain fault zone
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青藏高原大型地震断裂带的变形机制
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作者 张蕾 李海兵 +12 位作者 王焕 吴琼 杨少华 孙知明 司家亮 Marie-Luce CHEVALIER 曹勇 郑勇 潘家伟 刘栋梁 赵中宝 马绪宣 卢海建 《地球学报》 CAS CSCD 北大核心 2024年第6期854-870,共17页
近年来,大震频发,地震发生机制和地震断裂作用的研究已成为当今社会的重大课题,而断裂带的变形机制,尤其是大型地震断裂带的变形机制是认识断裂活动性和地震发生机制的关键。本文通过介绍青藏高原东缘龙门山断裂带和鲜水河断裂带的最新... 近年来,大震频发,地震发生机制和地震断裂作用的研究已成为当今社会的重大课题,而断裂带的变形机制,尤其是大型地震断裂带的变形机制是认识断裂活动性和地震发生机制的关键。本文通过介绍青藏高原东缘龙门山断裂带和鲜水河断裂带的最新研究成果,探讨青藏高原大型地震断裂带的变形机制,主要认识如下:(1)汶川地震使不同性质断层同时破裂,并在地壳浅部(~732.6 m深度)富流体断层泥中发生了熔融作用,颠覆了地震的传统认识,深化了对浅部断层力学性质的认识。(2)龙门山断裂带映秀—北川断裂带在晚三叠世曾经发生Mw7.4~7.9级的逆冲-左行走滑大地震,断裂岩的高磁化率各向异性度值指示了大地震活动。(3)汶川—茂县断裂带在新生代时期存在三期不同构造变形,青藏高原东缘不存在下地壳隧道流模式。(4)龙门山断裂带汶川—茂县断裂带曾经发生了摩擦热温度>500℃的大地震活动,孕震环境为还原性的含有硫化物的低温热液流体环境。(5)强震频发的鲜水河断裂带是藏东南物质外迁的主要边界,具有长期蠕滑变形行为,流体作用较强,流体的注入明显提高断层核部强矿物含量,促进了蠕滑断层的局部变强。上述认识丰富和完善了断裂作用理论,提高了对青藏高原大型地震断裂带变形机制的认识,为断裂带活动性、地震发生机制、地震危险性评估和防震减灾提供了科学依据。 展开更多
关键词 断裂岩 变形机制 龙门山断裂带 鲜水河断裂带 青藏高原
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龙门山山前带中段分层差异变形特征及成因
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作者 郑娜 何登发 +2 位作者 汪仁富 孟宪武 王莹 《地质科学》 CAS CSCD 北大核心 2024年第3期768-780,共13页
龙门山构造带是研究陆内构造变形活动的理想场所之一。龙门山山前带的构造变形整体具有纵向分段、横向分带、垂向分层的特点。为了明确龙门山山前带中段分层变形特征,并进一步探讨分层差异变形成因。本文应用浅表地质露头、数字高程与... 龙门山构造带是研究陆内构造变形活动的理想场所之一。龙门山山前带的构造变形整体具有纵向分段、横向分带、垂向分层的特点。为了明确龙门山山前带中段分层变形特征,并进一步探讨分层差异变形成因。本文应用浅表地质露头、数字高程与三维地震数据等资料,开展龙门山山前带中段构造样式的识别及分层差异解析,绘制典型剖面构造演化图,计算关键层位缩短量。研究表明:龙门山山前带发育多种类型的断层相关褶皱,其中,上三叠统叠瓦逆冲构造以及深部逆冲楔在龙门山山前带中段广泛发育。总体来看,龙门山山前带中段大致以嘉陵江组为界,呈叠瓦逆冲构造系统与深部中小尺度冲断构造系统垂向叠置的构造特征,滑脱层对分层变形起着控制作用。此外,岩性也影响着分层变形,嘉陵江组膏盐岩等区域性分布的软弱层在变形中发挥着传递应变的滑脱层作用;多期次变形的叠加也是导致龙门山山前带中段分层差异变形的重要原因。 展开更多
关键词 龙门山 山前带 构造样式 分层变形 多重滑脱
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2022—2023年四川泸定M_(S)6.8、M_(S)5.0和M_(S)5.6地震序列的发震构造及成因
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作者 张建勇 王新 +1 位作者 陈凌 刘杰 《地球物理学报》 SCIE EI CAS CSCD 北大核心 2024年第4期1471-1486,共16页
四川泸定2022年9月5日发生M_(S)6.8强震,随后10月22日和2023年1月26日又分别发生M_(S)5.0和M_(S)5.6强余震,主震和两次强余震的震中相距仅几公里却有着截然不同的震源机制解,因此,探究三者的发震构造、联系及成因至关重要.本研究利用国... 四川泸定2022年9月5日发生M_(S)6.8强震,随后10月22日和2023年1月26日又分别发生M_(S)5.0和M_(S)5.6强余震,主震和两次强余震的震中相距仅几公里却有着截然不同的震源机制解,因此,探究三者的发震构造、联系及成因至关重要.本研究利用国家地震台网记录到的这三次地震序列的连续波形数据及震相资料进行双差重定位,并进一步采取CAP波形反演方法和P波初动极性反演方法获得研究区M_(L)2.5+的79个余震震源机制解.结果显示,主破裂沿鲜水河断裂磨西段,破裂彻底,余震活动性不高.沿主断裂分布的余震具有明显的分段特征,断层近直立且西北浅东南深.主震及磨西段大部分余震均为走滑机制,是典型的印度—欧亚板块挤压旋转造成鲜水河走滑断裂带应力失稳触发的强震活动.发生在贡嘎山地区的余震是M_(S)6.8主震触发的震群活动,震级水平不高,分布弥散,并没有触发与主断裂共轭的燕子沟、海螺沟和磨子沟次级断裂,而是触发了与主断裂近平行的次级隐伏断裂——贡嘎山断裂.M_(S)5.0和M_(S)5.6两次强余震均发生在该次级隐伏断裂上,断层倾角40°~50°且震源深度较浅.贡嘎山地区拉张型地震活动明显不同于走滑型为主的鲜水河断裂带,可能是印度—欧亚板块挤压旋转作用下贡嘎山快速隆升而地表快速剥离导致局部因重力卸载而垮塌造成的,M_(S)6.8主震有明显的触发作用.三次泸定强震的发生,释放了磨西段及西侧贡嘎山地区部分应力,但并未改变"Y"字形交汇区强震发生的可能性. 展开更多
关键词 四川泸定地震 鲜水河断裂带 贡嘎山地区 发震构造 地震活动性
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SH波入射下山体-断层破碎带-隧道相互作用分析
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作者 黄磊 周颜婷 +2 位作者 刘中宪 段更月 张传秀 《防灾减灾工程学报》 CSCD 北大核心 2024年第4期870-880,共11页
采用一种高精度间接边界积分方程法(IBIEM),开展了山体-断层破碎带-隧道整体模型对地震波的散射作用模拟,考虑了三种影响因素:入射波强度、隧道与断层破碎带间距以及破碎带动力特性,模拟了其对山体表面及隧道地震动力响应的影响。研究... 采用一种高精度间接边界积分方程法(IBIEM),开展了山体-断层破碎带-隧道整体模型对地震波的散射作用模拟,考虑了三种影响因素:入射波强度、隧道与断层破碎带间距以及破碎带动力特性,模拟了其对山体表面及隧道地震动力响应的影响。研究结果表明:断层破碎带的存在使得山体-断层破碎带-隧道整体系统内相互作用更加复杂,山体表面位移幅值以及隧道的位移和应力幅值主要呈现放大效应,山体表面断层破裂处破坏异常严重,位移幅值陡增,可达10以上;在衬砌的拱肩、拱脚处的应力集中较为明显,衬砌的顶部和底部应力较小;地震波低频入射时,隧道内外壁应力和位移曲线较平缓,随着入射频率的增大,波的相干效应更加明显,衬砌隧道应力和位移发生空间重分布,出现峰值多段集中现象。 展开更多
关键词 山体 断层破碎带 隧道 地震波散射
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川西鲜水河、安宁河和龙门山断裂带地热水的水文地球化学特征及成因模式的讨论 被引量:1
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作者 吕国森 章旭 +4 位作者 张云辉 SAFONOVA Inna 黄豪擎 余中友 代倩 《中国地质》 CAS CSCD 北大核心 2024年第1期341-359,共19页
[研究目的]研究川西鲜水河断裂带、安宁河断裂带和龙门山断裂带地热水的水化学特征及成因模式,可为川西地热水资源的合理开发利用提供重要参考依据。[研究方法]本文运用水文地球化学、热储温度计算、氢氧同位素等方法分析了分布在3条断... [研究目的]研究川西鲜水河断裂带、安宁河断裂带和龙门山断裂带地热水的水化学特征及成因模式,可为川西地热水资源的合理开发利用提供重要参考依据。[研究方法]本文运用水文地球化学、热储温度计算、氢氧同位素等方法分析了分布在3条断裂带上的48处典型温泉(地热井)的水化学组分、水化学过程、热储温度和深度、热水补给来源等特征,并探讨了其形成模式。[研究结果]结果显示:(1)鲜水河断裂带热水水化学类型以HCO_(3)-Na型为主;龙门山断裂带主要为SO_(4)-Na和Cl-Na型;安宁河断裂带包括HCO_(3)·Cl-Na、HCO_(3)·SO_(4)-Ca·Mg和Cl·SO_(4)-Na型等。(2)3条断裂带地热水组分主要受硅酸盐矿物溶解和离子交换作用控制。(3)鲜水河断裂带热储温度为129.6~210.6℃,深度为2532~4184 m,冷水混入比为66%~82%;安宁河断裂带热储温度为81~121.9℃,深度为2155~3519 m,冷水混入比为52%~95%;龙门山断裂带热储温度为108.2~153℃,深度为3573~5654 m,冷水混入比为68%~89%。(4)3条断裂带的地热水接受大气降雨补给,补给高程分别为鲜水河断裂带2493~5034 m、安宁河断裂带3235~3839 m和龙门山断裂带1628~4574 m。(5)鲜水河断裂带地热水的“δ^(18)O漂移”程度强于安宁河断裂带,龙门山断裂带部分地热水出现“δ^(18)O漂移”和“负向漂移”特征。[结论]基于本次研究得到的3条断裂带地热水成因模式,鲜水河断裂带地热水的开发潜力优于安宁河断裂带、龙门山断裂带,是四川省中高温地热资源开发利用的优势靶区。 展开更多
关键词 断裂带 地热水 水文地球化学 热储 补给来源 形成模式 地热地质调查工程 龙门山 四川西部
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广东省惠东县元坑钨锡多金属矿区地球化学特征及找矿方向探讨
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作者 廖静 赵新胤 +2 位作者 郭丽荣 朱沛云 王长全 《世界有色金属》 2024年第14期68-70,共3页
元坑钨锡多金属矿区位于佐坑幅北部,位于武夷成矿带粤东段,紫金-博罗大断裂与莲花山断裂带西带夹持区域。该区为一个受断裂构造控制的岩浆热液充填交代型矿床。矿体赋存于与岩体接触带附近且受断裂构造改造的下侏罗统青坑组变浅海潮坪... 元坑钨锡多金属矿区位于佐坑幅北部,位于武夷成矿带粤东段,紫金-博罗大断裂与莲花山断裂带西带夹持区域。该区为一个受断裂构造控制的岩浆热液充填交代型矿床。矿体赋存于与岩体接触带附近且受断裂构造改造的下侏罗统青坑组变浅海潮坪相砂岩中,北东向断裂及北西向断裂构造,具有硅化、角岩化、绿泥石化等地段是重要的找矿方向。 展开更多
关键词 钨锡多金属矿 地球化学 找矿方向 莲花山断裂带 广东省
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龙门山复杂构造带红星1井天然气勘探突破及其油气地质意义 被引量:2
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作者 杨跃明 白晓亮 +8 位作者 易海永 刘冉 马华灵 韩嵩 闫柯 彭思桥 陈延贵 王尉 钟佳倚 《天然气工业》 EI CAS CSCD 北大核心 2023年第2期1-14,共14页
龙门山复杂构造带位于四川盆地西部,是该盆地油气勘探的重点区带,近期风险探井——红星1井首次钻穿龙门山推覆构造体,揭示推覆带下盘存在原地构造,并且在中二叠统栖霞组测试获得12.66×10^(4)m^(3)/d高产工业气流。为了探究该风险... 龙门山复杂构造带位于四川盆地西部,是该盆地油气勘探的重点区带,近期风险探井——红星1井首次钻穿龙门山推覆构造体,揭示推覆带下盘存在原地构造,并且在中二叠统栖霞组测试获得12.66×10^(4)m^(3)/d高产工业气流。为了探究该风险探井天然气勘探突破所蕴含的油气地质意义,基于该井所获丰富的钻探资料,重建了推覆体地质模型,并在此基础上对线束三维地震资料进行精细处理解释,恢复了龙门山前山带构造模式,进而剖析了川西龙门山复杂构造带深层碳酸盐岩沉积、储层特征及油气成藏地质条件。研究结果表明:(1)龙门山推覆构造带具有“逆掩推覆、直立倒转、原地系统”3段叠加式地质结构,前山带推覆冲断带二叠系、三叠系地层受断层控制,具有重复倒转的特征;(2)推覆体下盘栖霞组钻遇地层和岩性组合与山前带双鱼石地区特征相同,均为台缘滩相沉积,白云岩储层大面积分布,进一步证实了该区原地构造带台缘相带滩相孔隙型白云岩储层连片大面积分布;(3)龙门山复杂构造带具备“多源供烃—断裂输导—侧向对接—隐伏保存”的油气成藏条件,红星1井测试结果证实,该复杂构造带前山带和山前带均具有良好的油气成藏条件,区带油气勘探前景广阔。 展开更多
关键词 红星1井 龙门山构造带推覆体 推覆带下盘原地构造 中二叠统栖霞组 工业气流 台缘带 孔隙型白云岩储层
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