Modeling and inversion of semi-airborne transient electromagnetic data

Abstract:

Semi-airborne transient electromagnetic (SATEM) is useful and cheap in fast geology survey. This kind of survey use a light aircraft hanging a receiver in the air. And a line source is put on the ground surface to transmit electromagnetic induction into the earth. We establish a fast algorithm to simulate the SATEM responses for layered earth. Different offsets, receiver heights and geometry positions of the receiver are compared in our forward simulation. We find the trend of response curves in each direction have very few differences with clear characteristics. We also try to invert the modeling result of SATEM using a L1 norm optimization. Both linear and non-linear inversion algorithm are compared to show the inversion results. For a global optimization with free initial model, the non-linear algorithm always give the correct model. While the linear inversion is greatly depend on the initial model. Finally, we invert real data of SATEM. The inversion resistivity model profile show reasonable geology information.