【摘要】 微动探测是利用地球表面的天然震动信号进行探测的被动源探测方法.相对于传统的物探方法,微动探测野外施工灵活,阵列形状多样,受施工场地限制小,对施工环境影响小.目前进行微动探测所用的地震检波器大多成本较高、重量和体积大,不便于运输与大规模布设.本文由微动探测方法的特点出发,优化改造了自行研发的低成本自存储式数字地震检波器,使其性能满足微动探测的需要.通过对地震计系统噪声的详细分析、微动探测原理的讨论,结合现场试验数据,探讨了该检波器应用于大规模微动探测的可行性.更多还原

【Abstract】 Microtremor survey is a kind of passive-source methods which uses ambient ground tremors for geological investigation.Compared with traditional geophysical methods,it is more flexible,cost-efficient,and environmentally friendly. Most currently used geophones are expensive and bulky,and therefore inconvenient to large-scale deployment.In this study,a nocable low-cost geophone was optimized to suit for large-scale microtremor survey.The method of optimization is based on the following four points:First,it selects a sensor through the analysis of the self-noise of to meet the needs of microtremor survey.Second,it chooses the right operational amplifier and AD conversion module.Third,it integrates design of the entire system without using external module.And fourth,it makes a low-cost design of the geophone system,including selection of low-cost hardware components and reducing the amount of software code.Finally,the optimized geophone was used in three areas with differentgeological conditions in order to verify the rationality of the improvement and the possibilities for large-scale microtremor survey.The purpose of optimization has been achieved in this research.The no-cable geophone wrights only 600 g,and the maximum average power cost does not exceed 0.1mW.The entire system costs less than 2000 RMB.The most important thing is the optimized geophone can record the microtremor signal from 0.5to 20 Hz effectively.Experiments show that in different geological conditions the geophone can be setup quickly and work smoothly and reliably.The results of microtremor survey experiments are consistent with the existing geological data.Because the new geophone is much cheaper than the existing microtremor survey equipment,it is possible to use it in low-cost large-scale survey.The optimized geophone has a very small volume and light weight,and can be rapidly emplacedinto a variety of detector arrays.After the emplacement of large number of geophones,it can easily and quickly conduct survey to twodimensional or three-dimensional velocity structure of the area.Such microtremor survey with environment-friendly and low-cost advantages has broad application prospects.更多还原