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１９９９年上半年全世界地震灾害总水平偏低,共发生Ｍｓ≥６地震４９次,其中Ｍｓ≥７地震３次。全世界地震造成的死亡人数总计为２１２８人,伤约６０００人;经济损失约１０亿美元。主要灾害地震发生在哥伦比亚、阿富汗、印度、伊朗和墨西哥 。 相似文献
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１９９８年上半年全世界共发生ＭＳ≥６地震３６次。全世界地震造成的死亡人数总计为９７９４人,伤１５１７３人;经济损失为５．３亿～８．１亿美元。１９９８年上半年全世界地震活动总水平与去年同期相同,但灾情较重于去年同期。主要灾害地震发生在阿富汗、土耳其、玻利维亚和中国张北－尚义地区。在南极海域地区发生８级大地震。 相似文献
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１９９７年全世界共发生ＭＳ≥６地震９５次,较大灾害地震１１次,死亡人数总计２８８２人,伤９４８３人,经济损失约２４０亿美元。 相似文献
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１９９７年上半年全世界共发生Ｍｓ≥６地震４１次，其中Ｍｓ≥７有３次，成灾有１３次。全世界死亡人数总计为２７４２人，伤８３７３人；经济损失为４亿￣８亿美元。主要灾害地震发生在伊朗、巴斯斯坦、印度和我国新疆伽师地区；从全世界范围看，１９９７年上半年地震灾情并不严重。 相似文献
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2000年全世界地震活动水平略高于往年，但地震灾情很轻，地震死亡人数总计240人，伤3096人，经济损失约3亿美元，2000年印度尼西亚是地震灾害最严重的国家。 相似文献
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2001年1－6月全世界发生的较重大灾害地震共计8次，地震共计造成17759人死亡，953人失踪，15．9万人受伤，经济损失约163．3亿美元。重大灾害地震发生在印度。 相似文献
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１９９６年世界地震活动总水平和地震灾害破坏程度均低于往年，地震死亡总数６０５人，经济损失总计约１０．１亿美元，该文综合介绍了１９９６年全世界地震灾害、地震破坏和伤亡情况，并就今后两年的地震灾害形势进行了估测。 相似文献
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2001年全世界灾害性地震综述 总被引：2，自引：0，他引：2
2001年全世界地震活动水平属于中等偏高,地震灾情比往年较重。地震死亡人数总计17 770人,伤15 9370人,经济损失约77亿美元。2001年印度是地震灾害最严重的国家。 相似文献
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本文简介从新疆叶城至西藏狮泉河的大地电磁测深剖面．它北起塔里木盆地，横跨昆仑山脉和喀喇昆仑山脉地区到冈底斯西段，全长８００余公里．探测结果表明，不同测点的地壳内部有的有两个低阻层，有的则只有一个低阻层，壳内第１低阻层的埋藏深度约１０－３５ｋｍ，第２低阻层的埋藏深度约３０－６５ｋｍ。在南昆仑缝合带以南，壳内低阻层的埋藏深度有从南向北不断加深的趋势；而在其以北的壳内低阻层的埋藏深度则与此相反．上地幔第１低阻层的埋藏深度约在１００－１５０ｋｍ之间，第２低阻层的埋藏深度约在３５０－５５０ｋｍ之间． 相似文献
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太白维山山前断裂活动特征的初步研究 总被引：1，自引：0，他引：1
本文立足于大量的野外第一手资料，综合解剖了太白维山山前断裂的几何结构，并就其运动学特征进行了初步探讨。认为：太白维山山前断裂第四纪以来的活动表现为正断型，其几何结构和运动特征都有着相同的分段性。我们将其划分为三段，西段结构简单，晚更新世以来无明显活动；中段结构复杂，一直强烈活动；东段活动强度较低。晚更新世晚期以来断裂（中段）的平均滑动速率０．４ｍｍ／ａ，全新世以来达到０．６７ｍｍ／ａ，而且这种速率 相似文献
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LATE QUATERNARY ACTIVITY OF THE CENTRAL SEGMENT OF THE DARI FAULT AND RESTUDY OF THE SURFACE RUPTURE ZONE OF THE 1947 M73/4 DARI EARTHQUAKE,QINGHAI PROVINCE 
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下载免费PDF全文 Bayan Hara Block is one of the most representative active blocks resulting from the lateral extrusion of Tibet Plateau since the Cenozoic. Its southern and northern boundary faults are characterized by typical strike-slip shear deformation. Its eastern boundary is blocked by the Yangze block and its horizontal movement is transformed into the vertical movement of the Longmen Shan tectonic belt, leading to the uplift of the Longmen Shan Mountains and forming a grand geomorphic barrier on the eastern margin of the Tibet Plateau. A series of large earthquakes occurred along the boundary faults of the Bayan Hara Block in the past twenty years, which have attracted attention of many scholars. At present, the related studies of active tectonics on Bayan Hara Block are mainly concentrated on the boundary faults, such as Yushu-Ganzi-Xianshuihe Fault, East Kunlun Fault and Longmen Shan Fault. However, there are also some large faults inside the block, which not only have late Quaternary activity, but also have tectonic conditions to produce strong earthquake. These faults divide the Bayan Hara Block into some secondary blocks, and may play important roles in the kinematics and dynamics mechanism of the Bayan Hara Block, or even the eastern margin of the Tibet Plateau. The Dari Fault is one of the left-lateral strike-slip faults in the Bayan Hara Block. The Dari Fault starts at the eastern pass of the Kunlun Mountains, extends eastward through the south of Yalazela, Yeniugou and Keshoutan, the fault strike turns to NNE direction at Angcanggou, then turns to NE direction again at Moba town, Qinghai Province, and the fault ends near Nanmuda town, Sichuan Province, with a total length of more than 500km. The fault has been considered to be a late Quaternary active fault and the 1947 M73/4 Dari earthquake was produced by its middle segment. But studies on the late Quaternary activity of the Dari Fault are still weak. The previous research mainly focused on the investigation of the surface rupture and damages of the 1947 M73/4 Dari earthquake. However, there were different opinions about the scale of the M73/4 earthquake surface rupture zone. Dai Hua-guang(1983)thought that the surface rupture of the earthquake was about 150km long, but Qinghai Earthquake Agency(1984) believed that the length of surface rupture zone was only 58km. Based on interpretation of high-resolution images and field investigations, in this paper, we studied the late Quaternary activity of the Dari Fault and the surface rupture zone of the 1947 Dari earthquake. Late Quaternary activity in the central segment of the Dari Fault is particularly significant. A series of linear tectonic landforms, such as fault trough valley, fault scarps, fault springs and gully offsets, etc. are developed along the Dari Fault. And the surface rupture zone of the 1947 Dari earthquake is still relatively well preserved. We conducted a follow-up field investigation for the surface rupture zone of the 1947 Dari earthquake and found that the surface rupture related to the Dari earthquake starts at Longgen village in Moba town, and ends near the northwest of the Yilonggounao in Jianshe town, with a length of about 70km. The surface rupture is primarily characterized by scarps, compressional ridges, pull-apart basins, landslides, cleavage, and the coseismic offset is about 2~4m determined by a series of offset gullies. The surface rupture zone extends to the northwest of Yilonggounao and becomes ambiguous. It is mainly characterized by a series of linear fault springs along the surface rupture zone. Therefore, we suggest that the surface rupture zone of the 1947 Dari earthquake ends at the northwest of Yilonggounao. In summary, the central segment of the Dari Fault can be characterized by strong late Quaternary activity, and the surface rupture zone of the 1947 Dari earthquake is about 70km long. 相似文献
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SURFACE TRACKS AND SLIP RATE OF THE FAULT ALONG THE SOUTHERN MARGIN OF THE WUWEI BASIN IN THE LATE QUATERNARY 下载免费PDF全文
下载免费PDF全文 The fault along the southern margin of the Wuwei Basin, located in the eastern Hexi Corridor, NW China, plays an important role in the thrust fault system in the northern Qilian Mountains. The activities of this fault resulted in the generation of the Gulang earthquake(MS8.0) in 1927. Based on remote sensing image interpretation, geological and geomorphic observations in the field and 14C geochronological dating results, we conducted a detailed research on the geometry and kinematics of the fault. According to the discontinuous geometric distribution and variable strike directions, we divide this fault into 5 segments: Kangningqiao Fault(F1), Nanyinghe Fault(F2), Shangguchengcun-Zhangliugou Fault(F3), Tajiazhuang Fault(F4)and Yanjiazhuang Fault(F5). Results indicate that this fault, with a total of 60km long trace at the surface, has been active since the late Pleistocene. It behaves predominantly as a thrust fault and is accompanied with a locally sinistral strike-slip component along the Nanyinghe Fault(F2). Intensive activities of this fault in Holocene have caused extensive occurrence of dislocated landforms along its strike. Some measured displacements of the dislocated geologic or geomorphic units, combined with the 14C dating results, yield a vertical slip rate of (0.44±0.08)mm/a on this fault in Holocene, and a sinistral strike-slip rate of (1.43±0.08)mm/a on the Nanyinhhe Fault (F2) in late Pleistocene. 相似文献
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LATE-QUATERNARY ACTIVITY OF THE YALAHE FAULT OF THE XIANSHUIHE FAULT ZONE,EASTERN MARGIN OF THE TIBET PLATEAU 下载免费PDF全文
下载免费PDF全文 LIANG Ming-jian CHEN Li-chun RAN Yong-kang LI Yan-bao WANG Dong GAO Shuai-po HAN Ming-ming ZENG Di 《地震地质》1979,42(2):513-525
Complex geometrical structures on strike-slip faults would likely affect fault behavior such as strain accumulation and distribution, seismic rupture process, etc. The Xianshuihe Fault has been considered to be a Holocene active strike-slip fault with a high horizontal slip rate along the eastern margin of the Tibetan plateau. During the past 300 years, the Xianshuihe Fault produced 8 earthquakes with magnitude≥7 along the whole fault and showed strong activities of large earthquakes. Taking the Huiyuansi Basin as a structure boundary, the northwestern and southeastern segments of the Xianshuihe Fault show different characteristics. The northwestern segment, consisting of the Luhuo, Daofu and Qianning sections, shows a left-stepping en echelon pattern by simple fault strands. However, the southeastern segment(Huiyuansi-Kangding segment)has a complex structure and is divided into three sub-faults: the Yalahe, Selaha and Zheduotang Faults. To the south of Kangding County, the Moxi segment of the Xianshuihe Fault shows a simple structure. The previous studies suggest that the three sub-faults(the Yalahe, Selaha and Zheduotang Faults of the Huiyuansi-Kangding segment)unevenly distribute the strain of the northwestern segment of the Xianshuihe Fault. However, the disagreement of the new activity of the Yalahe Fault limits the understanding of the strain distribution model of the Huiyuansi-Kangding segment. Most scholars believed that the Yalahe Fault is a Holocene active fault. However, Zhang et al.(2017)used low-temperature thermochronology to study the cooling history of the Gongga rock mass, and suggested that the Yalahe Fault is now inactive and the latest activity of the Xianshuihe Fault has moved westward over the Selaha Fault. The Yalahe Fault is the only segment of the Xianshuihe Fault that lacks records of the strong historical earthquakes. Moreover, the Yalahe Fault is located in the alpine valley area, and the previous traffic conditions were very bad. Thus, the previous research on fault activity of the fault relied mainly on the interpretation of remote sensing, and the uncertainty was relatively large. Through remote sensing and field investigation, we found the geological and geomorphological evidence for Holocene activity of the Yalahe Fault. Moreover, we found a well-preserved seismic surface rupture zone with a length of about 10km near the Yariacuo and the co-seismic offsets of the earthquake are about 2.5~3.5m. In addition, we also advance the new active fault track of the Yalahe Fault to Yala Town near Kangding County. In Wangmu and Yala Town, we found the geological evidence for the latest fault activity that the Holocene alluvial fans were dislocated by the fault. These evidences suggest that the Yalahe Fault is a Holocene active fault, and has the seismogenic tectonic condition to produce a large earthquake, just like the Selaha and Zheduotang Faults. These also provide seismic geological evidence for the strain distribution model of the Kangding-Huiyuansi segment of the Xianshuihe Fault. 相似文献
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EVIDENCES OF THE LATE QUATERNARY ACTIVITY OF THE ANGREN SEGMENT OF THE YARLUNG TSANGPO FAULT ZONE 下载免费PDF全文
下载免费PDF全文 The Yarlung Tsangbo fault zone, one of the most important geological interfaces in the Yarlung Tsangbo suture zone which is a huge geotectonic boundary with nearly east-west-trending in southern Tibet Plateau, has undergone a long-term tectonic evolution. Studying this fault zone can help us understand the development and evolution history of the suture zone and the tectonic mechanism of subduction-collision about the Tibet Plateau, so it has always been a hot topic in the field of geology. Most of existing data suggest that the current tectonic activity in southern Tibet is given priority to the rift system with nearly north-south-trending, and the Yarlung Tsangbo fault zone with nearly east-west-trending has relatively weaker activity since late Quaternary. There are only some evidences of Holocene activity found in the Lulang town section near eastern Himalayan syntaxis, and there are few reports about the reliable geological evidences of late Quaternary activity of the section on the west of Milin County of the fault zone.
Based on image interpretation, field investigation and chronological method, we found several fault profiles along the Yarlung Tsangbo fault zone near the Angren Lake in this study. These profiles reveal that loose fault gouge has been developed on the fault plane which nearly extends to the surface and offsets the loess sediments and its overlying alluvial-proluvial gravels. The loess is characterized by coarser grains, higher content of fine sand and tiny small gravels. The results of the two OSL dating samples collected in the loess are(94.68±6.51)ka and(103.84±5.14)ka respectively, showing that the loess revealed at the Angren site should be the middle-late Pleistocene sand loess distributed on the high-terraces along the Yarlung Tsangpo River. Consequently, the Angren segment of the Yarlung Tsangpo fault zone is active since the late Quaternary. In addition, synchronous left-lateral offsets of a series of small gullies and beheaded gullies can be seen near the profiles along the fault, which are the supporting evidence for the late Quaternary activity of the fault.
However, the segment with obvious geomorphology remains is relatively short, and no evidence of late Quaternary activity have been found in other sections on the west of Milin County of the Yarlung Tsangpo fault zone. Existing data show that, in the southern Tibet, a series of near NS-trending rift systems are strongly active since the late Quaternary, cutting almost all of the near east-west-trending tectonic belts including the Yarlung Tsangpo fault zone. In addition, majority of the earthquakes occurring in southern Tibet are related to the NS-trending rift systems. Tectonic images show that the Angren segment locates between the Shenzha-Dingjie rift and the Dangreyong Lake-Gu Lake rift. These two adjacent rifts are special in the rift system in southern Tibet:Firstly, the two rifts are located in the conversion position of the trend of the whole rift system; Secondly, the size of the two rifts varies significantly between the north side and the south side of the Yarlung Tsangbo fault zone. Thirdly, the Shenzha-Dingjie rift seems to be of right-lateral bending, while the Dangreyong Lake-Gu Lake rift shows left-lateral bending. These characteristics may lead to the fact that the amount of absorption and accommodation of the rift activities in the north side of the Yarlung Tsangbo fault zone is larger than that in the south side during the migration of the plateau materials, leading to the differential movement of the block between the two sides of the fault zone. Therefore, the Yarlung Tsangbo fault zone possesses the accommodating tectonic activity, of course, the intensity of this accommodating activity is limited and relatively weaker, which may be the reason why it is difficult to find large-scale tectonic remains characterizing the late Quaternary activity along the fault zone. The scale of the rift system in southern Tibet is systematically different between the two sides of the Yarlung Tsangbo fault zone, so it cannot be ruled out that there are also weak activities similar to the Angren segment in other sections of the fault zone. 相似文献
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本文分析了1987年9月23日日环食期间,我国14个电离层站和1988年3月18日日全食期间两个站的垂测仪和偏振仪记录,并综合50年代以来历次日食电离层效应的观测结果,证实:1.E层和F1层光食效应明显,F2层动力学效应显著;2.f0F2存在日食日值大于、小于或等于控制日值三种典型情况;3.TEC食变曲线有凹陷和不凹陷两种典型情况,甚至出现日食日值大于控制日值的异常现象. 本文对F2层和外电离层的动力学特征作了定性讨论,认为:空间等离子体温度急剧下降和沿场扩散是F2层和外电离层日食效应的最主要因素;而磁赤道上空等离子体的沿场扩散、“喷泉”效应,热层风和全（环）食带方位是影响位于磁赤道异常区各电离层站日食电离层效应的主要因素. 相似文献
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WANG Hu RAN Yong-kang CHEN Li-chun LIANG Ming-jian GAO Shuai-po LI Yan-bao XU Liang-xin 《地震地质》2018,40(5):967-979
The Anninghe Fault has been suggested as an important segment of the fault system along the eastern boundary of the Sichuan-Yunnan faulted block in the southeastern region of the Tibetan plateau. Reliable determination of the Late Quaternary slip rate on the Anninghe Fault is very helpful and significant for revealing deformation mechanism and kinematic characteristics of the Sichuan-Yunnan faulted block, which further helps us understand fault activity and seismic potential of the region. However, previous studies were focused mainly on the northern segment of the Anninghe Fault, while slip rate on its southern segment has been less studied. Therefore, in this paper, we chose two sites at Dashuigou and Maoheshan on the southern segment of the Anninghe Fault, and used high-resolution images of unmanned aerial vehicle (UAV)photogrammetry technology, detailed field survey, multiple paleoseismic trenching and radiocarbon dating methods to constrain slip rate on the southern fault segment of the Anninghe Fault. Specifically, we suggest that the slip rate at the Dashuigouo site is narrowly constrained to be~4.4mm/a since about 3￣￣300a￣￣BP based on a linear regression calculation method, and speculate that a slip rate of 2.6~5.2mm/a at the Maoheshan site would be highly possible, although we poorly constrained the whole deformation amount of the two branch faults at the Maoheshan site from multiple paleoseismic trenching. The data at the two sites on the southern segment show a consistent slip rate compared with that of the northern segment of the Anninghe Fault. Moreover, considering a similar paleoseismic recurrence interval on the two segments of the Anninghe Fault from previous studies, we further suggest that the fault activity and deformation pattern on the two segments of the Annignhe Fault appears to be well consistent, which is also in agreement with the regional tectonic deformation. 相似文献
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本文在研究和分析环境因子对断层测量年周变和季节性变化影响的基础上，归纳出断层形变测量年周变的变化规律，并针对不等周期观测资料，建立了形变测量的准线性动态数学模型，最后，对门源地震有异常的扁都口资料用上述模型进行了处理，结果是比较满意的。 相似文献