摘要
本文采用Ｐｏｗｅｌｌ直接搜索定位方法对北京西北地区（３９°－４１°Ｎ，１１４°－１１７°Ｅ）１９７９—１９９２年３月发生的３４８个地震重新定位。通过震相到时的复核和补充、定位速度结构模型的修定以及定位程序的改进等措施，改善了定位效果。结果表明，重新定位后给出震源深度的地震数从原来的１３２个增至３１３个；定位结果均方根残差的均值从０．８０±０．４０ｓ降至０．４５±０．１８ｓ；各台Ｐ波到时残差下降；有近１０％的地震震中位置移动了１０ｋｍ以上，它们多位于北京地震遥测台网边缘地区。重新定位后的地震震中集中分布于怀安、宣化、怀来、琢鹿等山间盆地内部并与盆地边缘断裂有关。此外，地震还分布于山区和平原的交界地带。
This study relocated 348 microearthquakes which occurred in Beijing and its neighbouring areas (39°-41°N, 114°-117°E) during 1979-March of 1992. Precision of hypocenter locations is improved by rechecking and supplementing readings of arriving times of the seismic phases used, testing and selecting appropriate crustal model, and modifying the computer program, After the relocation, the number of earthquakes with focal depth determination has been increased to 313 from the previous 132. The overall average RMS residual of arriving times has been reduced to 0. 45±0.18s from the previous value of 0. 80±0. 40s. For nearly 10 per cent of the relocated hypocenters, which are mostly in border region of the area covered by the Beijing Telemetered Seismic Network, have been shifted more than 10km.Epicenters of the relocated earthquakes cluster in the intermountainous basins, such as the Huai'an,Xuanhua, Huailai and Zhuolu basin, and are related with the basin boundary faults between mountainous area and sedimentary plain.
出处
《中国地震》
CSCD
北大核心
1995年第3期222-230,共9页
Earthquake Research in China
基金
国家科学技术委员会和国家地震局85-907-04-01课题
关键词
地震
重新定位
震源深度
活动断裂
微震
Relocation of earthquakes, Crustal model, Focal depth, Active faulting
