Application of ultra-short-time linear array ambient noise imaging technology to detect shallow geological structures
Ambient Noise Tomography(ANT)techniques have been widely used to image the deep structure of lithosphere,while recent years have also seen great efforts for applying this techniques for shallow subsurface imaging.However,the high frequency surface wave signal is difficult to recover accurately due to the non-uniform near-surface field sources.The scheme for improving the Signal-Noise-Ratio(SNR)at the expense of time will greatly limit the application of ANT in engineering exploration.This paper showcases the application of ultra-short-time ANT techniques in the detection of shallow geological structures.With the ultra-short-time(1 h)linear array seismic ambient noise data recorded in the Yingcheng city of Hubei Province,we used the multi-channel analysis of passive surface waves to extract the phase-velocity dispersion curve from the virtual shot set,and obtained the two-dimensional shear-wave velocity through inversion.The results show that the generated scheme can estimate surface wave signals with high SNR,obtain high-resolution dispersion energy,and pick up high-precision phase velocity.The inversed velocity values are in good agreement with the well logs,and the velocity image effectively reveal the strata structures＜150 m in the survey area,which proves that the ultra-short time ANT technology has great potential for detecting the shallow geological structures.
万方数据
维普
