中国大陆中东部Ms≥8.0级特大地震发震背景初步分析

 从构造地貌、地质体特征及其物理力学性质、现今GPS位移场、活动断裂与现代构造应力场和能量场等方面探讨中国大陆中东部部分Ms≥8.0级特大地震发震背景。初步认为，地震是地壳局部或区域活动的表现，诱发地震的主因来自地球内部地应力、能量聚集和瞬间释放；发生地震的部位一般是地壳构造活动带或地壳结构的薄弱带，诸如活动断裂带等；活动断裂在发展演化过程中，当其穿过构造地貌、刚性结晶基底等特殊地质环境时，其活动受阻，引起地应力和能量集中。当地应力和能量积累超过岩体(石)强度，导致岩体(石)破裂，诱发地震；活动构造、地质体特征及其物理力学性质是地震发生的必要条件，地应力和能量集中是地震发生的充分条件。最后，提出中国大陆中东部中长期需重点关注的区带及工作建议。

PRELIMINARY ANALYSIS OF EARTHQUAKE OCCURRENCE BACKGROUNDS OF Ms≥8.0 CATASTROPHIC EARTHQUAKES IN MIDDLE AND EAST PARTS OF CHINESE CONTINENT

The earthquake occurrence backgrounds of Ms≥8.0 catastrophic earthquakes in the middle and east parts of Chinese Continent are discussed from aspects of tectonic landform，geological mass features and its physico-mechanical properties，present GPS displacement field，active fault，contemporary tectonic stress and energy field，and so on. Preliminary results show that earthquake，which is triggered by a sudden release of the concentrated geo-stress and energy in the interior of the earth，is one kind of activities in local or regional crust；and that the location of earthquake is always the active tectonic zone or weak belt in the crust，such as active fracture belt，etc.；and that the geo-stress and energy are always concentrated in the evolution process of active fracture belt in the crust while the active fracture belt passing through and being blocked by the special geological environments，such as tectonic landform，rigid crystalline basement，etc.. When the concentrated geo-stress and energy exceed the strength of rock or rock mass，the rock or rock mass will be broken，so an earthquake will be triggered. Active tectonics and geological mass features and physico-mechanical properties are necessary conditions for earthquake occurrence，and geo-stress and energy concentration are sufficient conditions for earthquake occurrence. At last，the key region which should be paid attention to for a mid-long term in the middle and east parts of Chinese Continent and the working suggestions are proposed.