摘要
利用华北丰富的历史地震资料,通过研究地震与块体活动的联系,揭示了地震高潮期的形成过程。认为地震高潮期成组强震的孕育与区域块体的运动方式相联系。一个地震活动期可分为二个阶段,在前期块体边界的运动是很不平衡的,各组地震主要是由于各局部范围若干闭锁段破裂和破裂间相互作用的结果,当沿块体边界的破裂发展到一定程度时,这些边界所围的地块就会进入以整体运动为主的阶段,这时块体边界的运动具有一定程度的同步性,加之闭锁段破裂后不再重新闭锁,从而导致块体边界闭锁段由弱到强渐进式的破裂过程,直至一组强闭锁段完成破裂,形成地震活动高潮。这是成组强震形成的根本原因,另外强震间的诱发作用也是强震成组发生的重要原因。最后概述了如何利用以上模式预测地震高潮期的时间、强度和主体活动场所。
The strong earthquake usually occur in groups in China. With plenty of historic earthquake data in North China, this article analyses the correlation between earthquakes with M≥5.0 and movement of tectonic blocks and discovers the preparatory process of strong earthquakes in groups or the climax seismic activity period in this area. The conclusion is that the pattern of large earthquakes in groups is related with the evolution of block movement. A long seismic activity period can be divided into two phases. During the first phase, the movement of each part of block is rather lopsided. A group of earthquakes are mainly result from ruptures of several locked segments and interaction among ruptures in local region. When the ruptures that goes along boundaries of tectonic block has reached a certain level, the block surrounded the boundary will be changed into the state based on the movement in whole, meanwhile the movements of the boundaries of the block should be synchronous in a certain level. Furthermore, after one locked region has ruptured, it will not be locked again, which leads to such rupture process from weak to strong along the tectonic block boundaries till a group of strong locked regions complete rupture and come into a seismic activity climax period. This is the essential reason for resulting in the strong earthquakes in groups. In addition the induced effect among large earthquake is another factor in earthquakes in groups. Finally, this article summaries how to forecast the appearance time, average intensity and occurrence location before a group of strong earthquakes according to the model described above.
出处
《地震》
CSCD
北大核心
2005年第3期9-19,共11页
Earthquake
基金
"十五"中国地震局重点科研项目(100501-05-01)
关键词
成组强震
孕育过程
中长期预报
华北地区
Strong earthquakes in group
Preparatory process
Long- and Mid-term prediction
North China region
