小当量激发的远距离信号检测研究

为了研究利用小当量震源进行远距离探测的可能性，通过现场试验进行了研究.野外实验采用1次大当量激发和16次小当量激发，研究结果表明：①有可能利用数十公斤当量的炸药实现200km距离的探测；②在激发条件相同（或相近）时，不同当量的激发波形滤波后存在一定的相似性；③依据人工震源可重复性采用以下的激发组合方式和处理方法能够有效提高信噪比：针对大当量激发与小当量激发波形的相似性，利用大当量激发的波形作模板与小当量激发的波形作相关，可判断台站是否接受到小当量激发的信号并检测其震相到时信息.针对小当量激发波形的相似性，采用小当量多次激发的方式，通过N次根加权叠加方法，能有效提高记录的信噪比和震相识别精度.

Study on weak signal detection of small shot in regional scale deep exploration

In recent years more and more active sources are used to explore underground structures in regional scale deep seismic exploration. In order to study the possibility of remote detection using small shot, we study the shooting mode and corresponding data-processing methods using field experiment. The field experiments used a big shot and 16 small shots. The results of the study showed that: ① Using dozens of kilograms of explosives the signal can be detected at distances up to 200 km; ②Active source has a certain degree of repeatability among different shots; ③This paper presents the following shooting mode and signal detection method based on the similarity of different shots: In light of the similarity between the signals of big shot and small shot, this paper presents a cross-correlation method using signal from big shot signal with high SNR and small shot signal to detect weak small shot signal, the method can effectively detect the small shot signal and pick up the start time of phase, this method can help us make full use of past seismic exploration data records. Considering the similarity between the excited signals, shooting repeatedly can be an effective way, we use the linear stack and N-th root weighted stack method, the method can effectively improve the clarity of the signal.