云南地区地震精确定位及其构造意义分析
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摘要
运用双差定位法,对云南区域数字地震遥测台网记录的1999~2003年云南地区ML≥1.0地震进行重新定位,得到3 000多个地震的精确定位结果。重定位结果显示,在东经100°和103°线附近存在两个震源深度较深的区域,最深达50km,刚好对应金沙江—红河断裂带的北段和小江断裂带。这一结果一方面揭示出这两条深大断裂与地震活动之间存在密切关系,另一方面也表明重定位结果在震源深度和空间分布上都较以前有明显改善。同时,姚安、大姚地震序列的重定位结果也说明双差定位法是一种比较好的地震定位方法。
We use double difference location method to relocate 1999-2003 M_L≥1.0 earthquakes recorded by the Yunnan regional digital seismic network,and obtained above(3000) accurately located results.They show there are two deep earthquake belts near the 100° E and 103°E longitude lines(the maximum depth reaches to 50 km),just respectively accord with the north section of the Jingshajiang-Honghe fault zone and the Xiaojiang fault zone.This fact not only discloses the close relationship between two deep fault zones and the seismicity but also proves that the relocation results are greatly improved in focal depth and spatial distribution.In addition,the relocation results of the Dayao and Yaoan Earthquake sequences also show that the double difference location method is more effective.
We use double difference location method to relocate 1999-2003 M_L≥1.0 earthquakes recorded by the Yunnan regional digital seismic network,and obtained above(3000) accurately located results.They show there are two deep earthquake belts near the 100° E and 103°E longitude lines(the maximum depth reaches to 50 km),just respectively accord with the north section of the Jingshajiang-Honghe fault zone and the Xiaojiang fault zone.This fact not only discloses the close relationship between two deep fault zones and the seismicity but also proves that the relocation results are greatly improved in focal depth and spatial distribution.In addition,the relocation results of the Dayao and Yaoan Earthquake sequences also show that the double difference location method is more effective.
引文
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[2]Gomberg J S,Shed lock K M,Roecker S W.The effect of S-wavearrival tim es on the accuracy of hypocenter estimation[J].BSSA,1990,80(6):1605-1628.
[3]W aldhauser F,E llsworthW L.A Double-D ifference Earthquake Lo-cation A lgorithm:Method and Application to the Northern HaywardFault,Californ ia[J].BSSA,2000,90(6):1353-1368.
[4]Prejean S G,E llsworth W L,Zoback M D,et al.Fau lt structureand k inematics of the Long Valley Caldera region,Calforn ia,re-vealed by h igh-accuracy earthquake hypocenters and focal m echa-n ism stress inversions[J].JGR,2002,107(4),2355-2373.
[5]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[J].中国科学(D辑),2003,3(增刊):129-134.
[6]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[J].地震学报,2004,26(2):115-120.
[7]Geiger L.Herdbestimm ing bei Erdbeben aus den Ankunftszeiten[J].K.Ges.W iss.G tt.,1910,4(3):331-349.
[8]Fréchet J.S ismogenèse et doub lets sism iques[D].Thèse d’E tat,Un iversitéScientifique etMéd icale de G renob le,1985.
[9]宋方敏,汪一鹏,俞维贤,等.小江活动断裂带[M].北京:地震出版社,1998.
[10]苏有锦,秦嘉政.川滇地区强地震活动与区域新构造的关系[J].中国地震,2001,17(1):24-34.
[11]徐彦,苏有锦.云南地区中小地震精定位和Lg尾波Q值研究[D].硕士研究生学位论文,云南大学,2005.
[12]苏有锦,刘祖荫,蔡明军,等.云南地区强震分布的深部地球介质背景[J].地震学报,1999,3(21):313-322.
[13]汪缉安,徐青,张文仁,等.云南大地热流及地热地质问题[J].地震地质,1990,12(4):367-377.
目录