Abstract: The comprehensive study based on combining geophysical prospecting with geological data indicates that there are two problems in the survey of active fault in city with the Quaternary deposit cover layer. One is the limitation of the stratigraphic position of the upper faulted point for active index. The other is the finiteness of the effective depth and resolution of exploration method. Since the upper fa ul ted point depth o f prospecting is greater than the actual depth, as a result, some active fault may fail to detect and underestimate seismic risk of fault, it is concerned with the damage earthquake occurring in some area in recent years. It is necessary to solve the above- mentioned problems in the survey of active fault in city.

Key words: Active fault, Upper faulted point, Resolution