关于芦山地震地点预测判定的讨论

Study on predicting the epicenter of the M7.0 Lushan Earthquake

许多强震震例总结表明,在大地震前往往出现多种先兆性地震活动异常,可以作为强震危险区预测的重要依据[1,2]。回顾芦山地震前存在的地震活动图像异常有：川滇2008年开始新一轮大震活跃幕;沿E103°线分布的川滇东缘带是近期大地震的主体活动带;历史上川北M≥6级地震的原地复发,已出现4对,1327年天全地震离逝时间已680余年;1500~2007年中国南北地震带东缘带（银川—通海）M≥7.7级地震空段内（康定—武都）,在2008年发生了汶川8级地震,北东向单侧破裂约300 km,但南段（映秀—天全）并未破裂,原缺震＂空段＂尚余一半;川滇几次中强以上地震后芦山—大邑均发生响应性诱发地震;中等地震月频次异常出现在2012年4月、7月和2013年2月;2013年2月18日四川盆地内三台—盐亭间先发生4.7级地震;四川及邻区大地震后5年左右的晚期强余震及后续强震活动;地震活动性参数b值异常等。这些异常图像的分析和应用有助于芦山地震的总结。

A lot of summaries of strong earthquakes indicate that many kind of precursory seismicities appeared before strong earthquakes.We take these precursory seismicities as a key factor to predict the epicenter of future strong earthquake.The seismicity precursory image before the M7.0 Lushan Earthquake is that the Sichuan- Yunnan seismic regions are in active episode since 2008.The eastern belts of Sichuan- Yunnan along the east longitude 103 line were recent main seismicity belts.From the historical earthquakes studies we find the north Sichuan province is an original seismic belts with the magnitude of M6.5 and there were 4 pair of earthquakes and 680 years have passed since the 1327 Tianquan Earthquake.From 1500 to 2007,the east boundary seismic belts along the south- north seismic belts from Yingchuan to Tonghai in China,was a gap of M≥7.7 from Kangdin to Tianquan.The 2008 M8.0 Wenchuan Earthquake broke a fault about 300 km long.But the southern segment did not.The induced response earthquakes along the Lushan- Dayu occurred after several strong earthquakes in Sichuan and Yunnan Provinces.The month times anomaly of precursory earthquakes with a middle level happen in three periods that is April,July 2012 and February 2013 respectively.In Sichuan basin there was an M4.7 Santai Earthquake on 18February 2013.There will be strong aftershocks after the strong earthquake of the 2008 M8.0 Wenchuan Earthquake in Sichuan and nearby regions.The abnormal parameter value- b of seismicity appears.