利用井下摆近震记录研究华北盆地沉积层速度结构  

Velocity Structure of Sedimentary Layer in North China Basin Based on Downhole Seismic Records

作　　者：朱音杰 刘丽[2] 杜航[3] 丁成[4] 刘檀[1] 石磊 ZHU Yinjie;LIU Li;DU Hang;DING Cheng;LIU Tan;SHI Lei(Shijiazhuang Central Seismic Station,Shijiazhuang 050021,China;Hebei Earthquake Agency,Shijiazhuang 050021,China;Jiangsu Earthquake Agency,Nanjing 210000,China;Chengde Central Seismic Station,Chengde 067000,China)

机构地区：[1]河北省地震局石家庄中心台,石家庄050021 [2]河北省地震局,石家庄050021 [3]江苏省地震局,南京210000 [4]河北省地震局承德中心台,河北承德067000

出　　处：《华北地震科学》2020年第3期44-48,共5页North China Earthquake Sciences

基　　金：河北省地震局监测、预测、科研三结合课题(DZ20190423055)。

摘　　要：收集了2015—2018年首都圈地区M1.0以上地震的波形数据,选取近场井下地震计观测记录,通过拾取直达P、S波及相应地表反射波的到时并测量其到时差,获得了台站下方地壳浅部300 m的P波、S波平均速度,并分析了波速的水平分布特征,结果表明,华北盆地近地表P波平均速度约为1.98 km/s,S波平均速度约为0.46 km/s,平均波速比约4.3;利用不同速度模型对27个地震事件进行定位,结果显示:沉积层模型可有效改善华北盆地地震定位精度。Based on the near-field waveform data recorded by downhole seismometers of M≥1.0 earthquakes in the capital circle area from 2015 to 2018,the average velocity of P-wave and S-wave of 300 m in the shallow crust below the station was obtained by using the time difference between the arrival time of the direct P-wave,S-wave and corresponding surface reflection wave phase,and the horizontal distribution characteristics of the wave velocity were analyzed.The results show that the average velocity of P wave is about 1.98 km/s,the average velocity of s wave is about 0.46 km/s,and the average velocity ratio is about 4.3.27 seismic events were located using different velocity models,the results show that the sediment model can effectively improve the north China basin earthquake location accuracy.

关 键 词：华北盆地 井下地震计 近震波形 沉积层 速度结构 

分 类 号：P315.6[天文地球—地震学]