| 唐山大震区深部构造的初步研究 |
| |
| 引用本文： | 邵学钟,张家茹,章思亚,陈纪平.唐山大震区深部构造的初步研究[J].地球物理学报,1986,29(1):28-41. |
| |
| 作者姓名： | 邵学钟 张家茹 章思亚 陈纪平 |
| |
| 作者单位： | 1. 国家地震局地质研究所;
2. 地质矿产部562队 |
| |
| 摘 要： | 本文介绍利用地震转换波测深法研究1976年7.8级唐山大震区深部构造的某些结果,得出了沿两条测线的深部构造剖面图。发现在极震区的数十公里的范围内,地壳和上地幔具有异常结构,在地壳中部比震区外围多出一个中间层位,埋深约12-20km,地壳上部界面向上挠曲,而莫霍面和上地幔顶部界面却强烈地向下挠曲,引起了震区岩石圈厚度的加大,在震区存在深浅不等的深部断裂。深部构造与震源分布的对比表明,唐山主震和绝大多数余震均分布在壳内中间层之上,有的甚至就分布在壳内中间层的上、下界面附近。转换波测深结果表明,本区地壳上地幔中强烈的升降差异运动可能是唐山大震的重要促发因素。
|
| 关 键 词： | 转换波 深部构造 唐山大震 唐山地震 s波 测线 地壳 时差 沉积盖层 频数曲线 |
| 收稿时间： | 1984-03-02 |
INVESTIGATION OF DEEP STRUCTURES IN TANGSHAN EARTHQUAKE AREA |
| |
| SHAO XUE-ZHONG,ZHANG JIA-RU,ZHANG SI-TA,CHEN JI-PING.INVESTIGATION OF DEEP STRUCTURES IN TANGSHAN EARTHQUAKE AREA[J].Chinese Journal of Geophysics,1986,29(1):28-41. |
| |
| Authors: | SHAO XUE-ZHONG ZHANG JIA-RU ZHANG SI-TA CHEN JI-PING |
| |
| Institution: | 1. Institute of Geology, State Seismological Bureau;
2. Brigade No 562, Ministry of Geology and Mineral Resources |
| |
| Abstract: | This paper discribes the results of investigation of deep structures in Tangshan earthquake area by using method of P to SV converted waves.6-7 groups of PS converted waves can be recognized in the area. The most stable of which are the groups of PSG and PSM coming from the top and bottom boundaries G and M of the crystalline crust. But in the earthquake source zone an additional PS wave group has been recognized in the middle part of the crust. Besides, the intensity, as well as the stability of the PSM wave group are reduced apparently, and the time delay of PS waves propagating through the source zone! is increased greatly in comparison with the sorrounding area of Tangshan. All these anomalies of PS wave characteristic indicate that the physical property of the crust layer has changed in the earthquake source zone.Two cross-sections of deep structure were obtained along the observed lines. The deep structures are very complicated beneath the Tangshan area which consists of sharp uplifting of the boundary G in upper part of the crust and subsidence of the boundaries in lower crust and upper mantle, appearence of an additional layer in the middle part of the crust, thickening of the middle and lower layers of the crust, and the presence of a set of deep faults in the vicinity of Tangshan earthquake area.Comparison of the deep structures with distribution of the hypocentres in the area shows that most of the hypocentres are located in the upper part of the crust between boundaries G and C, and the hypocentres of the mainshock and large aftershocks are distributed near the top-boundary of the middle layer of the crust. It means that the location of strong earthquakes is controlled by position of the middle layer of the crust. It is suggested that the strong vertical uplift-subsidence differential movement in the upper mantle beneath Tangshan area may be an important triggering factor for the occurrence of the Tangshan earthquake. |
| |
| Keywords: | |
| 本文献已被 CNKI 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 |
|
