2013年4月20日四川芦山M7.0级地震与余震精确定位及发震构造初探
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摘要
使用汇集在四川台网中心的固定台站、震后架设的流动台站、周边水库台站等震中距150km以内的震相数据,选用分层速度模型,对芦山7.0级地震及震后9天内的余震利用双差定位法进行了重新定位.给出了芦山7.0级地震的发震时刻为2013-04-20 08∶02∶46.8,震中位置30.278°N,102.989°E,震源深度16.67km,给出了3324次余震的双差定位结果,并对发震构造进行了分析.结果表明:芦山地震主破裂长度约40km,下倾宽度约20km,破裂视面积约800km2,主破裂沿南西走向,倾角约40°.余震震源优势深度为10～22km.余震沿南西走向,主要集中于大邑—名山断裂上盘.
The M7.0 Lushan earthquake and its aftershocks in 9 days were relocated by the double difference algorithm and layered velocity model,using the seismic phases within 150km recorded at stations including the fixed stations of the Sichuan earthquake network center,temporary stations and reservoir stations.The events analyzed include the main shock and its 3324 aftershocks.The results show that the original time of the main shock is 8 ∶ 02 ∶ 46.8 on 20 April 2013,hypocenter location 30.278°N,102.989°E and the focal depth 16.67 km.The main rupture is about 40 km long,20 km wide and of apparent area 800 km2.It strikes in southwest and dips about 40°.Most aftershocks occurred at depths 10~22 km,concentrating on the hanging wall of the Dayi-Minshan faults,forming a southwest-trending belt on the surface.Based on these and other data,this paper makes a preliminary analysis of the seismogenic structure of the Lushan event.
The M7.0 Lushan earthquake and its aftershocks in 9 days were relocated by the double difference algorithm and layered velocity model,using the seismic phases within 150km recorded at stations including the fixed stations of the Sichuan earthquake network center,temporary stations and reservoir stations.The events analyzed include the main shock and its 3324 aftershocks.The results show that the original time of the main shock is 8 ∶ 02 ∶ 46.8 on 20 April 2013,hypocenter location 30.278°N,102.989°E and the focal depth 16.67 km.The main rupture is about 40 km long,20 km wide and of apparent area 800 km2.It strikes in southwest and dips about 40°.Most aftershocks occurred at depths 10~22 km,concentrating on the hanging wall of the Dayi-Minshan faults,forming a southwest-trending belt on the surface.Based on these and other data,this paper makes a preliminary analysis of the seismogenic structure of the Lushan event.
引文
[1]张勇,许力生,陈运泰.芦山4.20地震破裂过程及其致灾特征初步分析.地球物理学报,2013,56(4):1408-1411.Zhang Y,Xu L S,Chen Y T.Rupture process of the Lushan
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[2]王卫民,郝金来,姚振兴.2013年4月20日四川芦山地震震源破裂过程反演初步结果.地球物理学报,2013,56(4):1412-1417.Wang W M,Hao J L,Yao Z X.Preliminary result ofprocess of April 20,2013,Lushan earthquake,Sichuan,China.Chinse J.Geophys.(in Chinese),2013,56(4):1412-1417.
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[6]张培震,徐锡伟,闻学泽等.2008年汶川8.0级地震发震断裂的滑动速率、复发周期和构造成因.地球物理学报,2008,51(4):1066-1073.Zhang P Z,Xu X W,Wen X Z,et al.Slip rates andrecurrence intervals of the Longmen Shan active fault zoneand tectonic implications for the mechanism of the May 12Wenchuan earthquake,2008,Sichuan,China.Chinse J.Geophys.(in Chinese),2008,51(4):1066-1073.
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[9]Waldhauser F,Ellsworth W L.Fault structure and mechanicsof the Hayward Fault,California,from double-differenceearthquake locations.J.Geophys.Res.,2002,107(B3),doi:10.1029/2000JB000084.
[10]王椿镛,吴建平,楼海等.川西藏东地区的地壳P波速度结构.中国科学D辑,2003,33(z1):181-189.Wang C Y,Wu J P,Lou H,et al.P-wave velocity structurein western Sichuan and eastern Tibetan region.Sci.ChinaSer.D-Earth Sci.,2003,33(Suppl.):181-189.
[11]吴建平,黄媛,张天中等.汶川MS8.0级地震余震分布及周边区域P波三维速度结构研究.地球物理学报,2009,52(2):320-328.Wu J P,Huang Y,Zhang T Z,et al.Aftershock distributionof the MS8.0Wenchuan earthquake and three dimensional P-wave velocity structure in and around source rigion.China.Chinse J.Geophys.(in Chinese),2009,52(2):320-328.
[12]朱介寿,曹家敏,刘舜化等.用人工地震初探川西地区的地壳结构.成都地质学院学报,1984,(3):111-122.Zhu J S,Cao J M,Liu S H,et al.A preliminaryinvestigation on crustal structure of western Sichuan byexplosion seismology.Journal of Chendu College ofGeology(in Chinese),1984,3:111-122.
[13]杨智娴,陈运泰,郑月军等.双差地震定位法在我国中西部地区地震精确定位中的应用.中国科学(D辑:地球科学),33(S1):129-134.Yang Z X,Chen Y T,Zheng Y J,Yu X H.Accurate relationof earthquake in central-western China using the double-difference earthquake location algorithm.Sci.China Ser.D-Earth Sci.,2003,33(Suppl.):129-134.
[14]郑钰,杨建思.双差算法的剖析及参数对定位的影响.地震地磁观测与研究,2008,29(3):85-93.Zhen Y,Yang J S.Analysis of double-difference algorithmand the affect of its parameter in location.Seismological andGeomagnetic Observation and Research(in Chinese).2008.29(3):85-93.
[15]杨智娴,陈运泰.用双差地震定位法再次精确测定1998年张北—尚义地震序列的震源参数.地震学报,2004,26(2):115-120.Yang Z X,Chen Y T,Relocation of the 1998 Zhangbei-Shangyi earthquake sequence using the double-differenceearthquake location algorithm.Acta Seismological Sinica(in Chinese),2004,26(2):115-120.
[16]Deichmann N,Garcia-Fernandez M.Rupture geometry fromhigh-precision relative hypocentre locations of microearthquakeclusters.Geophys.J.Int.,1992,110(3):501-517.
[17]黄媛,吴建平,张天中等.汶川8.0级大地震及其余震序列重定位研究.中国科学(D辑:地球科学),2008,38(10):1242-1249.Huang Y,Wu J P,Zhang T Z,et al.Relocation of the MS8.0Wenchuan earthquake and its aftershock sequence.Sci.China Ser.D-Earth Sci.(in Chinese),2008,38(10),1242-1249.
4.20earthquake and preliminary analysis on disaster-causingmechanism.Chinse J.Geophys.(in Chinese),2013,56(4):1408-1411.
[2]王卫民,郝金来,姚振兴.2013年4月20日四川芦山地震震源破裂过程反演初步结果.地球物理学报,2013,56(4):1412-1417.Wang W M,Hao J L,Yao Z X.Preliminary result ofprocess of April 20,2013,Lushan earthquake,Sichuan,China.Chinse J.Geophys.(in Chinese),2013,56(4):1412-1417.
[3]曾祥方,罗艳,韩立波等.2013年4月20日四川芦山MS7.0级地震:一个高角度逆冲地震.地球物理学报,2013,56(4):1418-1424.Zeng X F,Luo Y,Han L B,Shi Y L,et al.The LushanMS7.0earthquake on 20 April 2013:A high-angle thrustevent.Chinse J.Geophys.(in Chinese),2013,56(4):1418-1424.
[4]林茂炳.简论龙门山南段末端地区构造发展史.成都地质学院学报,1993,20(3):46-51.Ling M B,A brief discussion on the tectonic evolutionalhistory of terminal region at the south section in Longmenmountains,Sichuan province.Journal of Chengdu Collegeof Geology(in Chinese),1993,20(3):46-51.
[5]白兰香,闻学泽.龙门山断裂带茂汶—汶川段的长期强震潜势.四川地震,1994,(3):51-58.Bai L X,Wen X Z.Seismic potential of long-term strongshock on the Maowen-Wenchuan segmeng of the Longmenshanfault zone.Earthquak Research in Sichuan(in Chinese),1994,3:51-58.
[6]张培震,徐锡伟,闻学泽等.2008年汶川8.0级地震发震断裂的滑动速率、复发周期和构造成因.地球物理学报,2008,51(4):1066-1073.Zhang P Z,Xu X W,Wen X Z,et al.Slip rates andrecurrence intervals of the Longmen Shan active fault zoneand tectonic implications for the mechanism of the May 12Wenchuan earthquake,2008,Sichuan,China.Chinse J.Geophys.(in Chinese),2008,51(4):1066-1073.
[7]赵珠,范军,郑斯华等.龙门山断裂带地壳速度结构和震源位置的精确修定.地震学报,1997,19(6):615-622.Zhao Z,Fan J,Zheng S H,et al.Presision determination ofthe crustal structure and hypocentral loctions in theLongmenshan thrust nappe belt.Acta Seismological Sinica(in Chinese),1997,19(6):615-622.
[8]Waldhauser F,Ellsworth W L.A double-differenceearthquake location algorithm:method and application to theNorthern Hayward Fault,California.Seism.Soc.Amer.,2000,90(6):1353-1368.
[9]Waldhauser F,Ellsworth W L.Fault structure and mechanicsof the Hayward Fault,California,from double-differenceearthquake locations.J.Geophys.Res.,2002,107(B3),doi:10.1029/2000JB000084.
[10]王椿镛,吴建平,楼海等.川西藏东地区的地壳P波速度结构.中国科学D辑,2003,33(z1):181-189.Wang C Y,Wu J P,Lou H,et al.P-wave velocity structurein western Sichuan and eastern Tibetan region.Sci.ChinaSer.D-Earth Sci.,2003,33(Suppl.):181-189.
[11]吴建平,黄媛,张天中等.汶川MS8.0级地震余震分布及周边区域P波三维速度结构研究.地球物理学报,2009,52(2):320-328.Wu J P,Huang Y,Zhang T Z,et al.Aftershock distributionof the MS8.0Wenchuan earthquake and three dimensional P-wave velocity structure in and around source rigion.China.Chinse J.Geophys.(in Chinese),2009,52(2):320-328.
[12]朱介寿,曹家敏,刘舜化等.用人工地震初探川西地区的地壳结构.成都地质学院学报,1984,(3):111-122.Zhu J S,Cao J M,Liu S H,et al.A preliminaryinvestigation on crustal structure of western Sichuan byexplosion seismology.Journal of Chendu College ofGeology(in Chinese),1984,3:111-122.
[13]杨智娴,陈运泰,郑月军等.双差地震定位法在我国中西部地区地震精确定位中的应用.中国科学(D辑:地球科学),33(S1):129-134.Yang Z X,Chen Y T,Zheng Y J,Yu X H.Accurate relationof earthquake in central-western China using the double-difference earthquake location algorithm.Sci.China Ser.D-Earth Sci.,2003,33(Suppl.):129-134.
[14]郑钰,杨建思.双差算法的剖析及参数对定位的影响.地震地磁观测与研究,2008,29(3):85-93.Zhen Y,Yang J S.Analysis of double-difference algorithmand the affect of its parameter in location.Seismological andGeomagnetic Observation and Research(in Chinese).2008.29(3):85-93.
[15]杨智娴,陈运泰.用双差地震定位法再次精确测定1998年张北—尚义地震序列的震源参数.地震学报,2004,26(2):115-120.Yang Z X,Chen Y T,Relocation of the 1998 Zhangbei-Shangyi earthquake sequence using the double-differenceearthquake location algorithm.Acta Seismological Sinica(in Chinese),2004,26(2):115-120.
[16]Deichmann N,Garcia-Fernandez M.Rupture geometry fromhigh-precision relative hypocentre locations of microearthquakeclusters.Geophys.J.Int.,1992,110(3):501-517.
[17]黄媛,吴建平,张天中等.汶川8.0级大地震及其余震序列重定位研究.中国科学(D辑:地球科学),2008,38(10):1242-1249.Huang Y,Wu J P,Zhang T Z,et al.Relocation of the MS8.0Wenchuan earthquake and its aftershock sequence.Sci.China Ser.D-Earth Sci.(in Chinese),2008,38(10),1242-1249.
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