基于地震仪与四分量钻孔应变仪共点观测Rayleigh波频散特性

Rayleigh Wave Dispersion Characteristics Based on the Observations from Seismometer and Collocated Four-Gauge Borehole Strainmeter

作为中国地震科学实验场建设的重要部分之一,深井地震综合观测系统建设项目在安宁河-则木河断裂带附近建成了一个深井地震观测实验系统,共建成10个井深300 m和2个井深1000 m综合地震观测井,其中包含了地震波观测和应变观测,通过将甚宽频带地震仪观测与四分量钻孔应变仪集成,形成地震与应变共点观测。应变仪与地震仪的采样率均设计为100 Hz,有利于获得高质量的远震、区域地震和近场微震的地震波和应变地震波观测数据。基于最早建成的地震综合观测深井之一--拖乌300 m深井数据,尝试采用地震波和应变地震波的振幅信息,基于共点相速度估计理论,获取了20~125 s周期范围内观测井局部的Rayleigh波相速度频散曲线。

As one of the important parts of the construction of the China Seismic Experi-mental Site,the borehole seismic observation system construction project has built an ob-servation array of borehole near the Anninghe-Zemuhe fault,consisted of 1o borehole with a depth of 300 meters and 2 borehole with a depth of 1000 meters.By integrating the broadband seismometer and the Four-Gauge Borehole Strainmeter(FGBS),the co-point observation of seismic and strain is formed.The sampling rate of both FGBS and seismom-eters is 100 Hz,which is conducive to obtain high-quality seismic and strain seismic wave data of teleseism,regional earthquakes,and near-field microseisms.In this paper,based on the data of 3o0-meter borehole Tuowu,one of the earliest comprehensive seismic obser-vation boreholes,we try to use the amplitude information of seismic waves and strain seis-mic waves,combining the theory of single-site estimation of phase velocity,to obtain the local Rayleigh wave phase velocity dispersion curve in the period of 20~125 s.