论文摘要
Earthquakes worldwide are known to be associated with active tectonics both regional and local scales. The aim of this paper is to present the regional seismotectonic setting and seismicity of recent years in golden triangle（including northern Thailand, northwestern Laos, northeastern Myanmar, and southern Yunnan of China） and its adjacent region, and to discuss the relationship between active faults and seismicity. This region lies in the Indochina Peninsula of southern extension of the Tibetan plateau, characterized by high level seismicity. Owning to being in multinational border zone and transportation inconvenience, research regarding the tectonic activity in this area is very deficient and scarce. This scarcity of faults investigation makes mitigation of earthquake hazards, assessment of seismic risk, and relations between ruptures and geologic structure very tenuous. With the implementation of silks-roads strategy and accelerated pace of construction projects such as hydropower stations, it is urgent to strengthen the research on the active tectonic and seismic risk assessment for this region. By the approach of geologic and geomorphic field observations along with analyzing the linear image features of satellite images, regional tectonics activities are studied. The golden triangle and adjacent area is a structural province characterized by NE striking left-lateral faults that include the Mong Hpayak, Nam Ma, Mae Chan, Luang Namtha, and Dien Bien Phu faults from north to south, they are all active in late Quaternary. The Mong Hpayak fault runs approximately NE45°from the Mong Tong of Myanmar, through Mong Hsat, Mong Phayak, Mong Yawng, then terminates in Menglun, with a total length of about 310 km. At Mengsong, the Mekong River forms a hairpin loop at the fault trace, the left-lateral dislocation of the Mekong River is about 9 km. Furthermore, streams of the Mekong River are synchronously offset left-laterally by the fault from 60 m to 600 m. The Nam Loi River, a tributary of Mekong River, flows from west to east, but after passing through Wan Tapao, it does not flow directly into the Mekong River, but turns north-east and then to south, forming two "V" shaped curvatures. At both tops of the "V" shaped loops, the Nam Loi River is offset left-laterally by 4.5 km and 7 km, respectively. An alluvial fan near Wan Tapao is displaced left-laterally around 150 m, and thus the slip rate of the fault is estimated to be about 3-5 mm/a according to the alluvial fan age. The Nam Ma fault, trending NE with a total length of 150 km, originates Mengla basin in southern Yunnan, extends into northwestern Laos and propagates in northeastern Myanmar. The fault displaced deposits of late Quaternary at many localities: the first terrace of Mekong river is offset at Sing Kok; 2.4 km west of Xiengkok, the fault displaced the bedrock and overlying diluvium which is（530±30） a.B.P. in age（dated by 14 C method）; at Nam Na, the second terrace of Nam Na river is lef
论文目录
文章来源
类型: 国际会议
作者: SONG Xianghui,WANG Shuaijun,WANG Fuyun,LIU Baofeng,GAO Zhanyong,YANG Yudong,MA Cejun
来源: 第九届世界华人地质科学研讨会 2019-06-01
年度: 2019
分类: 基础科学
专业: 地质学,地质学,地球物理学
单位: China University of Geoscience(Beijing)China Earthquake Administration,Geophysical Exploration Center
分类号: P315;P542
DOI: 10.26914/c.cnkihy.2019.028402
页码: 219-220
总页数: 2
文件大小: 163k
下载量: 2