青海茫崖—新疆若羌地震探测剖面及其深部构造的研究  

Seismic Profiling Between Mangnai,Qinghai and Ruoqiang, Xinjiang and Infrastructure Study

作　　者：姜枚[1] 许志琴[1] 薛光琦[1] 史大年[1] Gerard Wittlinger Georges Poupinet 董英君[1] 张春贺[1] 

机构地区：[1]中国地质科学院,北京100037 [2]Ecole et Observatoire de Science de la Terre,Strasbourg,France [3]LGIT,University Joseph Fourier,Grenoble,France

出　　处：《地质学报》1999年第2期153-161,共9页Acta Geologica Sinica

摘　　要：穿越NE向阿尔金断裂带,首次进行天然地震探测获取了大量远震与近震资料。对数据进行了层析分析、接收函数和震源定位的研究。提供了阿尔金断裂深部构造的新资料。地震层析资料表明,软流圈的大致深度在100 km、地壳各部位的速度特征有较大差异,推断南缘断裂产状较陡。沿此断裂出现的幔源物质,在层析图象上呈低速体。北缘的断裂带属高速带,但深部则为相对的低速体。接收函数的结果显示北缘断裂带在浅部产状缓。北缘断裂带在深部应与南缘断裂相会,可能正是塔里木地块的地壳向柴达木地块下部(向南东)插入的表现。可以认为,塔里木地块在岩石圈深部进入了青藏高原的下部,而阿尔金断裂带控制着青藏高原地块向北挤出。A tremendous amount of teleseismic and local seismic data have been obtained by the first natural earthquake recordings cutting through the Altyn fault system. Multiple methods such as seismic tomography, receiving functions and focus location are applied to the data, and informative results are produced on the deep features of the Altyn fault. The Altyn fault is composed on the surface of the northwest-trending Southern Altyn fault and Northern Altyn fault. Significant difference in velocity pattern in the crust can be seen from place to place, from which an inference is drawn that the Southern Altyn fault dips steeply to a depth of about 100 km with volcanic and earthquake activities occurring along. The mantle-derived materials on the surface, expressed by the low-velocity body in the tomographic image, comes supposedly deep from underneath the plateau. The Northern Altyn fault, in the contrast, is shown as a high-velocity zone, with a relatively low-velocity horizon below. The result from the receiving functions indicates evidently that the Northern Altyn fault dips gently in the shallow levels of the earth's crust. The Northern and Southern faults seem to meet in depth, which should be the indication of the Tarim crust wedging southeastwards under the Tibetan Plateau. The Tarim block has run beneath the Tibetan Plateau deep in the lithosphere, whereas the Altyn fault is constraining the plateau from extruding northwards. It is shown in the tomographic image that the rheosphere is at a depth of 100 km where a clear difference in the velocity pattern above and below the boundary can be seen. In addition, some focus locations related to the active Altyn fault are given.

关 键 词：阿尔金断裂 地震层析 新模型 地震探测 深部构造 

分 类 号：P542.5[天文地球—构造地质学] P631.4[天文地球—地质学]