Research On The Application Of Geophysical Exploration Technique In The Survey Of Surface Collapse Of Luan County, Hebei Province

Surface collapse is one of geologic hazards, which badly jeopardize the people's life and possessions, and restrict sustainable development of society and economy. They must be seriously prevented and controlled. This paper has reviewed the definition and classification of surface collapse, and the main problems, which can be resolved by geophysical exploration in the investigation of surface collapse, and introduced successful cases and practicability of comprehensive geophysical method. It is proved that transient electromagnetic method and shallow seismic exploration are comparatively effective in detail survey of surface collapse. It is expected that causes of surface collapse, potential karst, fracture zone and suffosion zones may be find out. It is hoped that the validity of these methods will be verified through this exploration, and that an economical and effective geophysical method can be confirmed in the investigation of karst collapse in Tangshan area. Moreover, this paper has introduced the principle of transient electromagnetic methods and shallow seismic exploration. On the basis of carefully analyzing geological, geophysical characteristics in the exploration area of Luan County surface collapse, Hebei Province, working devices and parameters of these two methods have been identified. It is concluded that the development of karst is cause of surface collapse by processing and interpreting of obtained data, and karst zone is circled in the exploration area.It is suggested that the breakup and corrosion of underlain Ordovician limestone is serious, karst develops, and that a northsouth-trending corrosion zone exist, depth of which increases from south to north. The combination of transient electromagnetic methods and shallow seismic exploration validly improved accuracy of the surface collapse exploration.