首页 | 本学科首页   官方微博 | 高级检索  
     检索      

帕米尔-兴都库什地区地震空间分布特征及应力场特征
引用本文:宁杰远,臧绍先.帕米尔-兴都库什地区地震空间分布特征及应力场特征[J].地球物理学报,1990,33(6):657-669.
作者姓名:宁杰远  臧绍先
作者单位:北京大学地球物理系, 北京 100871
摘    要:本文研究了兴都库什及帕米尔地区地震的空间分布.发现h<70km的地震分布广泛,h≥100km的地震形成-S形的倾斜中源地震带.在71.5°E以西,中源地震带倾向接近正北,倾角随深度变化,在深部接近垂直,且倾角自西向东逐渐变陡,在71.5°E以东,倾向逐渐由东南变为正南. 分析了121个mb≥5.0地震的机制解.浅源地震机制解的P轴大多位于NS和NNW-SSE方向,且多近水平,反映此区受到NS或NNW-SSE方向挤压.各剖面应力轴分布规律性强,在150km以下,总的趋势是机制解的T轴接近于倾斜的中源地震带的下倾方向,而P轴倾角较小且垂直于倾斜的中源地震带的走向.

关 键 词:应力场  地震带  帕米尔-兴都库什地区  
收稿时间:1988-05-06

THE DISTRIBUTION OF EARTHQUAKES AND STRESS STATE IN PAMIR-HINDUKUSH REGIONS
NING JIE-YUAN ZANG SHAO-XIAN.THE DISTRIBUTION OF EARTHQUAKES AND STRESS STATE IN PAMIR-HINDUKUSH REGIONS[J].Chinese Journal of Geophysics,1990,33(6):657-669.
Authors:NING JIE-YUAN ZANG SHAO-XIAN
Institution:Department of Geophysics, Peking University, Beijing 100871
Abstract:The distribution of earthquakes of Mb ≥ 4.0 in Pamir-Hindukush Regions was studied using the data from I.S.C. for the period from 1968 to 1982. The earthquakes which are shallower than 70 km formed four seismic belts striking from NE to SW. The earthquakes deeper than 100 km concentrated in a S-type belt which is about 700 km long. Series of cross sections perpendicular to the deeper seismic belt were taken. It is shown that the intermediate earthquakes formed an obvious and oblique seismic zone. In the west of 71.5°E, the dip direction of the zone is due North, the dip angle changes with depth and is nearly vertical below the depth of 150 km. The dip angle becomes larger gradually from West to East, the earthquakes deeper than 200km occured mainly in this zone. In the East of 71.5°E, the dip direction of the oblique seismic zone changes gradually from ES to due south. Few of earthquakes deeper than 100 km occured in East of 75.8°E.Eighty one fault plane solutions for earthquakes of Mb≥5.0 were obtained using the first motions of P wave. The stress state in this region were studied using the fault plane solutions obtained by this paper and other authers. The P axes for earthquakes shallower than 70 km are mostly in the North-South direction and nearly horizontal, it reflects that the crust is under North-South or NNW-SSE compression, the distribution of P axes for shallow earthquakes have obvious influence from the local tectonic movement. There are clear characteristics for the distribution of the axes of stresses in the oblique intermediate earthquake zone. In general, the T axes are nearly vetical and P axes are nearly horizontal; below 200 km, the directions of T axes are coincidant with that of the oblique seismic zone and P axes are perpendicular to the strike of the oblique seismic zone. The results shown that the distribution of shallow earthquakes may be correlated with the large faults, but the intermediate earthquakes may be correlated with some remains of subducting ocean slab.
Keywords:Stress field  Seismic belt  Pamir-Hindukush regions  
本文献已被 CNKI 维普 等数据库收录!
点击此处可从《地球物理学报》浏览原始摘要信息
点击此处可从《地球物理学报》下载免费的PDF全文
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号