西南地区热灾害链及其与芦山地震的关系

Temporal-spatial structure of thermal disaster chain in Southwest China and its relation with the Lushan earthquake

通过对西南地区干旱（森林大火）-洪涝（或冰冻）-地震灾害链的分析,发现＂4·20＂芦山地震震前出现了一系列与该灾害链相关的热异常现象,即：川滇地区自2009年以来,先后经历了跨年度干旱,并伴随森林大火,2012年5月中旬局地开始出现暴雨洪涝,还引发大量滑坡、泥石流等地质灾害,2013年初南方多地相继出现大雾、低温、冻害、雪灾,在此期间,川滇地区还发生了一系列4.0~6.0级范围内中强地震,随后于4月20日发生了芦山地震。此外,通过芦山地震考察,发现震前8~6h内出现喷水冒砂、天气闷热、狗狂吠等宏观异常,地震的同时震中地区出现爆炸、冒烟等现象,这些现象进一步说明芦山地震成因并非断层错动,而是地下热异常积累到一定程度后突然释放。同时,结合西南地区热灾害链结构推测,西南地区近期内仍将有强震发生。

According to the systemic analysis of abnormalities related with thermal before the＂4.20＂Lushan earthquake,we found that all the thermal abnormalities composed a drought（or forest fire）-flood（or frost）-earthquake disaster chain.The multi-year drought accompanying forest fires have occurred in Sichuan-Yunnan region since 2009.Then rainstorms and floods befell in this area since mid-May 2012,which also triggered many geological hazards such as landslides and debris flows.At the beginning of the year,fogs,low temperature,frost,and snowstorm happened in succession,while a series of MS4.0-6.0earthquakes happened before the Lushan earthquake.Besides,we investigate the Lushan earthquake and discovered that seismic macroscopic anomalies such as sandboils and waterspouts,muggy weather and dog barking furiously about 8-6hours before the earthquake,and the exploding and gas eruptions during the earthquake appeared near the epicenter.All the phenomena indicate that the genesis of Lushan earthquake is not fault movement but the sudden release of energy after the accumulation of heat underground.Finally,we speculate that the following strong earthquakes in Southwest China are on the way on the basis of the thermal disaster chain.