芦山地震后的微地震监测

The stress accumulated along active faults can be released via destructive earthquakes, such as the Lushan and Wenchuan earthquakes. It can also be released via micro tremors (or microseismics) that are a lot less energetic but a lot more abundant in number than great earthquakes。 The study of micro tremors is not only a very important part of the assessment of the fault activity, but also crucial to the understanding of the mechanism of destructive earthquakes and the infrasound waves associated with earthquakes. The micro tremors mentioned in this study refer not only to small earthquakes, but also to those earthquakes that are too small to be identifiable thus to be locatable using ordinary seismic network. Micoseismic study started as one method to assess the fault activity, but it has been well developed rapidly in the oil and gas (especially the shell gas) exploration industry. The major goal of this study is to explore the fault activity near Lushan earthquake using the technologies well developed in the oil and gas industry.

活动断裂带积累的应变能可能以强烈破坏性地震(比如芦山地震和汶川地震)的方式释放，但也可能以更多更频繁的微地震的方式释放。对微地震的研究不但是断裂活动性评估的一部分，也有利于我们对强震孕震机制和地震次声波产生机理的了解。本研究所指微地震包括大量常规地震台网很难识别并定位的小于1级甚至0级的极微震。微地震监测发源于对活动断裂带的研究，但在西方油气开采（特别是页岩气开发）中得到迅速发展。本研究主要目标是将在油气开发中已经得到较好发展的微地震监测技术用于芦山地震附近断裂带活动性研究。

汶川和芦山地震以后，龙门山断裂带及周边区域的地震活动性成为关注的焦点。特别是芦山和汶川地震之间的约60公里宽的地震空区的活动性引起了极大的争议。在这一背景下，本研究的目的就是监测芦山地震震区及其以北的地震空区的微地震分布，通过震源机制解等手段研究区域应力场分布。. 经过近一年的研究，已经取得了一系列初步成果：(1) 通过地震定位初步厘清了发震断层的地下展布形态；(2) 通过震源机制解揭示了芦山地震到汶川地震之间的应力分布的复杂性；(3)研究同时也发现汶川和芦山地震之间的地震空区形态上的复杂性。这些研究成果为龙门山断裂带地震活动性评价提供了必要的依据。. 目前为止，本项目已经提交SCI检索论文1篇（接收待刊），国内会议摘要5篇，国际会议摘要1篇，准备提交SCI检索论文1篇，会议摘要2篇。