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针对气枪主动源监测中相位加权叠加数据绝对到时拾取可能存在较大误差的问题,提出基于台站之间叠加信号波形的相似性,利用台站对波形的互相关得到更准确到时差的策略。在此基础上,将台站对双差地震速度成像方法直接用于台站对到时差数据,以确定地下介质的速度异常。本文利用长江安徽段气枪实验在庐江临时地震台阵接收到的数据进行了测试,发现基于波形互相关得到的到时差数据比绝对到时数据更准确。最后,采用台站对双差地震成像的方法,得到了庐江台阵覆盖区域的地壳三维速度异常模型,继而确定了该地区较大尺度的地下结构分布。
Aiming at the problem that the phase-weighted superposition data in the air-gun active source monitoring may have a large error when it is picked up absolutely, the similarity based on the superimposed signal waveforms between the stations is proposed. The strategy of using station-to-waveform cross-correlation to obtain a more accurate time difference is proposed . On this basis, the station-to-pair differential seismic velocity imaging method is applied directly to the station-to-arrival time difference data to determine the velocity anomaly of the underground medium. In this paper, we use the airgun experiment in the Yangtze River in Anhui Province to test the data received by the Lujiang temporary seismic array and find out that the time-difference data obtained based on the waveform cross-correlation is more accurate than the absolute time-lapse data. Finally, by using the method of station differential imaging, the three-dimensional crustal velocity anomaly model of the Lujiang array was obtained, and then the larger-scale subsurface structure distribution in the area was determined.