2013年4月20日四川芦山地震震源破裂过程反演初步结果
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摘要
使用远场体波资料和有限断层方法快速反演获得了2013年4月12日芦山地震的震源破裂过程模型,并计算了震中区理论烈度分布.结果显示这次地震是发生在龙门山断裂带南端的一次Mw6.7级的逆冲型地震,最大滑动量159cm,震中区烈度达Ⅷ—Ⅸ度(中国地震烈度表).这次地震的震源性质与汶川地震同为逆冲型破裂,主要破裂滑动发生在汶川地震后的库伦应力增加区域,表明汶川地震对这次地震有触发效应,在宏观上可视为汶川地震一次"迟到"的强余震.
The rupture process of the 20,Apr.2013,Lushan earthquake was fast estimated by finite fault model method using far field body waveform records.The predicted shakemap is subsequently calculated based on rupture fault model of this earthquake.Results show that the earthquake is an Mw6.7 thrusting event which occurred on the south part of Longmen Shan fault zone with 159 cm largest slip.By the predicted shakemap,the intensity of epicenter region should reached Ⅷ—Ⅸ on Chinese seismic intensity scale.The thrusting mechanism of Lushan earthquake is similar to that of Wenchuan earthquake.The earthquake rupture of this event occurred on the southern section of Longmen Shan fault where shows increase of Coulomb stress caused by the Wenchuan earthquake.This event may be triggered by the Wenchuan earthquake.On the view of macroscopic,this earthquake can be considered as an delayed strong aftershock of Wenchuan earthquake.
The rupture process of the 20,Apr.2013,Lushan earthquake was fast estimated by finite fault model method using far field body waveform records.The predicted shakemap is subsequently calculated based on rupture fault model of this earthquake.Results show that the earthquake is an Mw6.7 thrusting event which occurred on the south part of Longmen Shan fault zone with 159 cm largest slip.By the predicted shakemap,the intensity of epicenter region should reached Ⅷ—Ⅸ on Chinese seismic intensity scale.The thrusting mechanism of Lushan earthquake is similar to that of Wenchuan earthquake.The earthquake rupture of this event occurred on the southern section of Longmen Shan fault where shows increase of Coulomb stress caused by the Wenchuan earthquake.This event may be triggered by the Wenchuan earthquake.On the view of macroscopic,this earthquake can be considered as an delayed strong aftershock of Wenchuan earthquake.
引文
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[3]姚振兴,纪晨.时间域有限地震断层的反演问题.地球物理学报,1997,40(5):691-701.Yao Z X,Ji C.The inverse problem of finite fault study intime domain.China.Chinese J.Geophysics.(in Chinese),1997,40(5):691-701.
[4]Boore D M.Prediction of ground motion using the stochastic method.Pure and Applied Geophysics,2003,160:635-676.
[5]Tom Parson,Ji Chen,Kirb Eric y.Stress changes from the 2008Wenchuan earthquake and increased hazard in the Sichuan Basin.Nature,2008,454:509-510.
[6]单斌,熊熊,郑勇等.2008年5月12日M w 7.9汶川地震导致的周边断层应力变化.中国科学D辑:地球科学,2009,39(5):12-20.Shan B,Xiong X,Zheng Y,et al.Stress changes on major faults caused by Mw7.9Wenchuan earthquake,May12,2008.Sci China Ser D-Earth Sci,2009,52(5):593-601.
[7]邵志刚,周龙泉,蒋长胜等.2008年汶川M S 8.0地震对周边断层地震活动的影响.地球物理学报.2010,53(8):1784-1795.Shao Z G.Zhou L Q.Jiang C S.et al.The impact of Wenchuan earthquake on the seismic activity of surrounding faults.Chinese J.Geophys.(in Chinese),2010,53(8):1784-1795.
[8]闻学泽,张培震,杜方等.2008年汶川8.0级地震发生的历史与现今地震活动背景.地球物理学报,2009,52(2):444-454.Wen X Z,Zhang P Z,Du F,et al.The background of historical and modern seismic activities of the occurrence of the2008Ms8.0Wenchuan,Sichuan,earthquake.China.Chinese J.Geophys.(in Chinese),2010,52(2):444-454.