Joint inversion of multi-station receiver functions and gravity data for imaging Moho variations and average crustal v_P/v_S ratios

Crustal thickness and v_P/v_S ratio are two important parameters for understanding crustal structure and composition, which can help to study regional tectonics. Receiver function analysis has been widely used for determining crustal thickness and v_P/v_S ratio by the H-κ method or the H-κ-c method. However, it can only acquire average crustal thickness and v_P/v_S ratio beneath each seismic station, but cannot constrain their lateral variations among seisimic stations due to their sparse and irregular distribution. On the other hand, the gravity data has been widely used to derive the Moho variaitons, which has a good coverage and resolution laterally but poor resolution vertically. Therefore, in this study we have developed a new joint inversion method of receiver functions and gravity data to simultaneously invert for variations of Moho depths and average crustal v_P/v_S ratios in a region. The method takes advantage of complementary strengths of receiver functions and gravity data, and can simultaneously fit all receiver functions and gravity data in the region. The synthetic tests show that the proposed joint inversion method produces more reliable results than only receiver function analysis, especially for the crustal thickness.