| 华北盆地强震的震源模型兼论强震和盆地的成因 |
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| 引用本文： | 曾融生,朱露培.华北盆地强震的震源模型兼论强震和盆地的成因[J].地球物理学报,1991,34(3):288-301. |
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| 作者姓名： | 曾融生 朱露培 |
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| 作者单位： | 国家地震局地球物理研究所, 北京 100081 |
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| 摘 要： | 华北盆地自第三纪以来产生不均匀沉降,形成众多凹陷和隆起.传统的热张裂模型或是拉一分模型均不适用于华北盆地.我们根据反射和折射地震探测以及地震体波层析成象的结果,说明震源区附近存在Moho界面断裂,而且有明显的迹象表明,上地幔高温物质（低速度）向地壳下部入侵.因此,作者提出华北盆地强震以及凹陷形成的新模型,即在水平板块构造应力场的背景中,上地幔热物质向地壳下部入侵,它所产生的扰动应力场不仅在横向是不均匀的,而且在垂向也是不均匀的.它能够在地壳上部产生足够大的伸张应力场,同时在地壳中部或下部产生水平切应力场.这个新模型也能解释华北盆地的地壳厚度没有减薄,而地面热流又较大的现象. 由于地壳中力学性质随深度而改变,所以强震可能是由中部地壳的塑性形变以及上部地壳的脆性断层所组成的,即所谓两层破裂的震源模型.
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| 关 键 词： | 华北盆地 震源模型 盆地和强震的成因 |
| 收稿时间： | 1990-05-09 |
A SEISMIC SOURCE MODEL OF THE LARGE EARTHQUAKES IN NORTH CHINA EXTENSIONAL BASIN AND DISCUSSIONS ON THE GENETIC PROCESSES OF THE EXTENSIONAL BASIN AND EARTHQUAKES |
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| ZENG RONG-SHENG ZHU LU-PFI HE ZHENG-QING DING ZHI-FENG SUN WEI-GUO.A SEISMIC SOURCE MODEL OF THE LARGE EARTHQUAKES IN NORTH CHINA EXTENSIONAL BASIN AND DISCUSSIONS ON THE GENETIC PROCESSES OF THE EXTENSIONAL BASIN AND EARTHQUAKES[J].Chinese Journal of Geophysics,1991,34(3):288-301. |
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| Authors: | ZENG RONG-SHENG ZHU LU-PFI HE ZHENG-QING DING ZHI-FENG SUN WEI-GUO |
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| Institution: | Institute of Geophysics, State Seismological Bureau, Beijing 100081 |
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| Abstract: | Since the Tertiary, numerous intervening depressions and upliftings have been produced in the North China Basin due to the differential sinking of the Basin. The North China Basin can not be interpreted properly with the thermal-rifting and the pull-apart models. A broken Moho was observed near the epicemral area of Tangshan earthquake from DSS result, and a prominent low velocity zone extending from the uppermost mantle to the middle crust was found near the epicentral area from 'he results of seismic computerized tomography. They indicate that a magmatic body of high temperature had penetrated form the uppermost mantle to the middle crust through the broken Moho. A new model for interpreting the seismoge-netic process and the generation of depressions in the upper part of the crust is suggested by the authors of present paper. A smaller stress field due to the injection of magma from the uppermost mantle to the middle crust is produced in addition to the horizontal tectonic stress field, which is more uniform in a large-scale area. The disturbance due to the injected magma varies in both lateral and vertical directions. It produces a considerably large ex-Tensional force in the upper part of the crust and a horizontal shear stress in the middle and lower parts of the crust at the same time. This model also avoids the difficulty that the cru-stal thickness doesn't decrease, while the heat flow is high in North China Basin.Since the rheology varies with the depth, a two-level seismic source of a large earthquake may comprise a brittle deformation in the upper part of the crust and a ductile deformation in the middle or even the lower curst. |
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| Keywords: | North China Basin Seismic Source Model Genetic processes of basin and earthquakes |
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