2003年大姚6.2级、 6.1级地震序列震源位置及震源区速度结构的联合反演

地震 ›› 2009, Vol. 29 ›› Issue (2): 12-24.

2003年大姚6.2级、 6.1级地震序列震源位置及震源区速度结构的联合反演

周龙泉¹, 刘杰¹, 马宏生², 周俊杰³

1.中国地震台网中心, 北京 100045;
2.中国地震局地震预测研究所, 北京 100036;
3.河北工程大学资源学院, 河北邯郸 056038

收稿日期:2008-02-13 修回日期:2008-12-08 出版日期:2009-05-31 发布日期:2021-10-18
作者简介:周龙泉(1976-), 男, 江西南丰人, 2005年获博士学位, 主要从事地震层析成像和地震预测等研究。
基金资助:
国家科技支撑计划项目(2006BAC01B02-01-02)资助

Simultaneous Inversion for the 2003 Dayao M6.2 and M6.1 Earthquakes Sequence Locations and Velocity Structure in the Hypocentral Area

ZHOU Long-quan¹, LIU Jie¹, MA Hong-sheng², ZHOU Jun-jie³

1. China Earthquake Networks Center, Beijing 100045, China;
2. Institute of Earthquake Science, CEA, Beijing 100036, China;
3. College of Natural Resource, Hebei University of Engineering, Handan 056038, China

Received:2008-02-13 Revised:2008-12-08 Online:2009-05-31 Published:2021-10-18

摘要/Abstract

摘要： 采用震源位置和速度结构的联合反演方法确定2003年大姚6.2级、 6.1级地震序列的分布和震源区的速度结构。该方法首先确定研究区的速度结构, 然后在该速度结构的基础上对地震重新定位。结果表明: ① 大姚6.2级地震序列明显分为地震较密集的东南段和地震较稀疏的北西段, 而且这两段存在一定的错动, 速度结构也显示出高、低速交界带在错动处具有转折特点; ② 大姚6.2级地震序列在深度上呈“V”字形分布, 这与该地区呈倒三角形分布的低速体相对应, 即余震主要分布在高、低速交界带附近; ③ 大姚6.2级、 6.1级地震的破裂区都位于倒三角形低速体的东南侧, 6.2级地震沿高、低速交界带往下破裂, 而6.1级地震沿高、低速交界带往上破裂; ④ 6 km深度的速度分布显示震源区具有高、低速度体交替呈四象限分布特征, 而且余震主要沿北西向的高低速交界带分布; ⑤ 大姚6.2级主震的东南侧的高、低速交界带处的低速体速度值较北西侧低速值高, 其对6.2级地震往东南方向破裂具有阻碍作用, 即东南侧处于能量积累状态, 有利于6.1级地震的发生。

关键词: 大姚地震, 联合反演, 地震定位, 速度结构

Abstract: We determined the 2003 Dayao M6.2 and M6.1 earthquakes sequence location and velocity structure of the hypocentral area by a simultaneous inversion method. First the velocity structure is determined by the method, and then earthquake location is performed on the basis of velocity structure. The results show that the M6.2 earthquake sequence can divided into two segments, the relatively dense southeast segment and the relatively sparse northwest segment, and there is a dip offset between the two segments,characterized by a turn. At the transitional zone of high and low velocity structures. The distribution of the M6.2 earthquake sequences shows a “V” shape along the depth, which corresponds to the reversing triangle shape of low velocity structure, namely, the aftershocks of M6.2 are distributed along the transitional zones of high and low velocity structures. The rupture zones of the M6.2 and M6.1 earthquakes are located on the southeast side of the reversing triangle shape of low velocity structure. The mainshock of M6.2 ruptured downwards and the mainshock of M6.1 ruptured upwards along the transitional zones of high and low velocity structure. The velocity structure at the depth of 6km shows that there is the quadrant distribution of high and low velocity structures and the aftershocks of the M6.2 and M6.1 earthquakes are distributed along the northwest transitional zones of high and low velocity structure. The value of low velocity structure at the southeast side of the M6.2 earthquake is higher than the value of low velocity structure at the northwest side, which is disadvantageous to the rupture southeastward for the M6.2 earthquake and is advantageous to the energy accumulation and occurrence of the M6.1 earthquake.

Key words: Dayao earthquakes, Simultaneous inversion, Earthquake location, Velocity structure

中图分类号:

P315.7

周龙泉, 刘杰, 马宏生, 周俊杰. 2003年大姚6.2级、 6.1级地震序列震源位置及震源区速度结构的联合反演[J]. 地震, 2009, 29(2): 12-24.

ZHOU Long-quan, LIU Jie, MA Hong-sheng, ZHOU Jun-jie. Simultaneous Inversion for the 2003 Dayao M6.2 and M6.1 Earthquakes Sequence Locations and Velocity Structure in the Hypocentral Area[J]. EARTHQUAKE, 2009, 29(2): 12-24.

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