Modeling of bedrock topography in an urban area through micro-gravity data

Micro gravity data was collected in a crowded street in tehran where a subway terraintunnel is to be excavated. the data is corrected for the gravity effects of the surroundingdensely built up area with diverse buildings and the bouguer gravity anomalies arecomputed. the residual gravity anomalies are prepared by removing a trend surface.upward continuation is used to remove the gravity effects of shallow synthetic anomaliessuch as subsurface galleries and canals. then the up-ward residual gravity anomalies areused to determine the depth of the bedrock (hezar darreh formation). a 2d inversionalgorithm is applied on the data and the model is constrained based on prior geologyinformation provided from the bore holes