关键词: 浅层地震反射勘探, 电成像, 联合成像, 地质构造, 城市活断层

Abstract: In exploration of a shallow active fault in urban area,seismic reflection survey and electrical imaging are the two main geophysical tools.Both of them can be implemented independently.However,the complexity of subsurface geologic tectonics,especially the lateral irregularities close to fault and geologic tectonic zones could result in great deviation from the detected results.In the meantime,the geophysical inversion has not only one result.These would lead to a large difference of stacked velocity model established only by its own information from real one in seismic data processing.In consequence,the geologic interpretation would be harmed.On the other hand,electrical imaging is very sensitive to the lateral irregularities of rock properties but has weak resolution in depth.Therefore,the two techniques can just compensate each other and a joint detection can be carried out to interpret a complex geologic tectonics more reasonably.In this paper,experiment on the joint detection using seismic reflection survey and electrical imaging is made basing on the simple relationship between resistivity and seismic P-wave velocity:ρ_α∝|Z|²∝V_p².It is shown that a reasonable quasi 2-D seismic stacked velocity model can be obtained referring to the resistivity image from electrical imaging.In the end,the reasonable seismic reflection and time-depth conversion profiles are gotten,which is helpful for further understanding and more reasonably interpreting the geological structures.

Key words: seismic reflection survey, electrical imaging, joint imaging, geological structure, active fault in urban area