10:00 AM - 10:15 AM
[PPS08-05] Estimation of Moho depth under lunar basins by using only the GRAIL gravity data
Keywords:moon, crust, gravity, GRAIL, Moholovicic discontinuity
In this study, we show a new method which doesn't require ad hoc assumptions of crustal thickness nor downward continuation filter, but assumes the simple shape of Moho uplift. Under the assumption that the Moho is uplifted like an axisymmetric cylinder beneath Crisium basins , the observed Bouguer gravity anomalies can be expanded in the Bessel-Fourier coefficients . Then we find the best fit parameters such as radius, height and depth of cylinder. Thus, the depth of surrounding crust is estimated to be 37.9±7.7 km. Our estimate is consistent with that of the analysis result of moonquake data measured at Apollo 12 & 14 landing sites. This result indicates that the new method can estimate crustal thicknessby gravity data alone and independently from seismic data. Here we assumed a simple morphology of mass anomalies beneath Crisium basin, however, the top surface of the cylinder as well as surrounding Moho boundary shall be laterally variable. In further research we evaluate an influence of the shape, crustal flexure, and other effects.