发震断层对微、宏观震中偏离的影响分析:以新疆地区为例

大量震例表明通常情况下地震的微、宏观震中有很大的偏离,如何在震后快速正确估计微、宏观震中偏离的程度,是目前迫切需要解决的重要问题。以新疆地区为例,详细研究了新疆地区M s≥6.5级的历史地震微、宏观震中偏离与发震构造的空间分布关系。新疆地区主要的发震断层类型包括逆断层、逆冲走滑断层及走滑断层3种。针对不同的发震断层类型初步提出了根据发震构造快速估计6.5级以上强震微、宏观震中偏离的模型和方法。微、宏观震中偏离的理想方向取决于破裂的性质(如单侧破裂、双侧破裂),很难确定理想宏观震中在发震断层的确切位置,具有一定的随机性,但是地震微、宏观震中的偏离方向与新疆整体构造应力方向具有一致性,宏观震中位置一般位于发震断层上或其附近,在实际应用过程中可以认为宏观震中就在断层上。

Analysis on the Impact of Seismogenic Fault on the Micro-and Macro-epicenter Deviation:Taking Xinjiang Area as an Example

How to estimate the micro-and macro-epicenter deviation is a key problem to earthquake emergency and rescue response.Taking Xinjiang area as an example,this study investigated the relationship between micro-and macro-epicenter deviation and seismogenics structures,and provided a new method for the fast determination of possible macro-epicenter based on the micro-epicenter and seismogenics structures for the earthquakes Ms≥6.5.There are 3 types of faults in Xinjiang,including the thrust fault,the thrust-slip fault and the strike-slip fault.The deviation of the ideal micro-epicenter direction depends on the nature of rupture(such as unilateral rupture,bilateral rupture),so it is difficult to determine the exact location of the ideal micro-epicenter in the seismogenic fault,and it is a certain randomness,but the deviation of the micro-and macro-epicenter is consistent with the overall direction of tectonic stress direction.The macro-epicenter location is located in or near the seismogenic fault in actual application.