新型绿色人工震源探测(中浅部)地壳结构的研究

In the past 20 years, through transplantation of marine seismic exploration techniques and incorporation of coding/decoding techniques in the information science, we have developed and improved a technique for investigation of underground structure and its temporal changes using airgun-excited artificial seismic sources in water bodies on land. This technique of generating artificial sources is green and environmentally friendly with signal propagation distance reaching about 200 km and exploration area about 100000 km2, which can be utilized to monitor physical processes of regional earthquakes and underground property changes due to charging/discharging processes in underground oil and gas reservoirs. In the continental interior, earthquakes and volcanoes mostly occur at about 10-20km depths in the mid-uper crust, and rapid development of urban regions brings new necessities for investigation of urban underground environment (less than 1km depth). For traditional Earth structural exploration, it is more difficult to investigate shallow and middle crust, and we are facing many theoretical, methodological and technical issues. Therefore, this project aims to obtain full physical nucleation processes of the detected earthquakes through years of highly repetitive and continuous shot data based on our developed techniques and systems on airgun seismic sources. And we also attempt to obtain reliable urban underground environmental images in some pilot regions.

过去20年，通过移植海洋地震勘探技术，并借鉴信息科学中的编码解码技术，我们发展和完善了在陆地水体中利用气枪激发人工地震波，探测地下结构及其变化的技术。这种人工震源技术绿色环保，环境友好，信号传播距离达到200km，探测范围可达10万km2 以上，可用于监测区域内发生的地震的物理过程，以及地下油气储库充储引起的地下环境变化。大陆内部的地震和火山多发生在地下10—20km的地壳中上部，而城市的飞速发展则提出了城市地下环境（小于1km深度）探测的新需求。对于传统的地球探测而言，中浅部的地壳探测难度更大，面临着理论、方法和技术等方面的诸多新问题。因此，本项目拟在过去发展的人工震源技术系统地基础上，进行常年高重复性的连续探测，期望得到实际测量到的地震的物理孕育全过程，并得到试点地区城市可信的地下环境图像。

项目立足于新型人工绿色震源的研发、应用拓展和应用推广。在项目的推动下，成功地实现了便携式小型气枪的研发和野外测试；开展了多个新型甲烷震源的野外实验，从中发现问题，并进行改进，使甲烷震源日益成熟。两种震源的推出和完善为城市地下空间探测和监视提供了可行的震源方案。围绕绿色震源地下结构探测应用，项目在接收系统（如密集节点台阵、分布式光纤传感（DAS）等）上也进行了多种有益的探索，特别是大力推进DAS在地震学的应用，为城市地震学发展指出了新的方向。基于这些绿色震源和接收系统，项目在微弱信号处理、精细的地下介质波速变化监测和城市浅层结构成像等数据处理方面也获得了新的进展和成果。因此，项目通过不同方向的同步探索，逐步摸索出针对地下结构探测和动态监测等应用，独特的全链路的可实用化的研究路线。