针对地下介质动态变化监测研究中的信噪比、震源可重复性和波速精确测量等关键问题,利用大容量气枪震源,构建了一套高性能的主动探测技术系统,该系统包括气枪震源激发和信号接收,并在河北、云南和新疆等地的内陆水库和人工水体等不同激发环境,开展了探索性试验研究.试验结果表明:①气枪震源激发频率低,能量强,具有高度的可重复性、可通过叠加提高信噪比、探测距离大、绿色环保等特征,是一种理想的低频震源;②该探测技术系统操作简单,易控制,自动化程度高,探测精度高,能观测到固体潮引起的连续变化,可应用于区域尺度地下介质动态变化监测和开展4D地震学研究;③气枪震源激发产生的信号震相丰富,有较强的S波,为研究地壳介质特性、应力分布及其动态变化等提供了新的技术路线.
The key issues are the signal to noise ratio (SNR),repeatability of the seismic source and accuracy in velocity measure in the dynamics monitoring of subsurface.We constructed a high-performance active monitoring system with large volume airgun source,consisting of airgun excitation and signal reception,in the experiments in inland reservoirs and artificial water body in Hebei,Yunnan and Xinjiang.The results showed that:(1) The airgun source is an ideal lowfrequency source,with the characteristics of low frequency,high-repeatability,long detection distance,environmental protection and low cost.(2) The active monitoring system can be applied to the active monitoring of subsurface and 4D seismology on the regional scale,with simple structure,easy operation and maintenance,strong automation,high detection precision,and have observed the continuous change caused by the Tide.(3) The signal of airgun includes abundant seismic phase,and has strong S wave,which provides a new technology to study on the medium properties,crustal stress distribution and dynamic variety.