川滇地区中小震重新定位与速度结构的联合反演研究
Simultaneous inversion of small earthquake relocation and velocity structure in Sichuan-Yunnan area
马宏生 1张国民 2周龙泉 3刘杰 3邵志刚 2夏红4
作者信息
- 1. 中国地震局地震预测研究所,北京,100036;中国地震局地球物理研究所,北京,100081
- 2. 中国地震局地震预测研究所,北京,100036
- 3. 中国地震台网中心,北京,100036
- 4. 中国地震应急搜救中心,北京,100049
- 折叠
摘要
通过震源与速度结构联合反演,利用2000年4月至2006年3月云南和四川区域地震台网给出的P波初至走时资料,确定了川滇地区的三维速度结构,同时获得了川滇地区6 642次中小地震的重新定位结果.结果表明:①川滇地区地震震源平均深度随震级增大而加深的特征明显,地震震级越大,震源深度越深,但震源下界不超过25 km;②在瑞丽-龙陵、丽江-小金河以及龙门山等断裂带以西地区,震源深度偏浅,大多在15 km以上,15 km深度以下地震稀少;③川滇地区中小地震分布具有与强震相同的地壳深部介质背景,震源大多分布于正、负异常过渡区的速度相对较高一侧,而其下方主要为低速异常分布.
Abstract
Using the data of P wave travel time recorded at Yunnan and Sichuan local networks from April 2000 to March 2006, we implemented a simultaneous inversion of earthquake relocation and velocity structure, and got the new location of 6 642 small and medium earthquakes in Sichuan-Yunnan region. The results show that: ①There is an obvious relationship between the focal depth and the magnitude. The bigger the magnitude, the deeper the focal depth, but all the focal depths values are shallower than 25 km; ② There are few earthquakes occurred at the depth deeper than 15 km in regions west of Ruili-Lon-gling, Lijiang-Xiaojinhe and Longmenshan faults; ③ Small and medium earthquakes have the similar seismogenic background as large earthquakes. Along the transitional zone of high velocity and low velocity, most of the earthquakes happened at the higher velocity side, and usually there is a low velocity zone below where earthquakes happened.
关键词
川滇地区/联合反演/重新定位/速度结构Key words
Sichuan-Yunnan area/Simultaneous inversion/Earthquake relocation/Velocity structure引用本文复制引用
基金项目
国家科技支撑计划(2006BAC01B02-01-02)
出版年
2008
NETL
NSTL
维普
万方数据