[S-GD22_1PO1] Gravity and Geoid

[SGD22-P06] Estimation of the density structure beneath the Kanto Distinct, Japan, by 3-D gravity inversion

*Tatsumi EDO¹, Akihiko YAMAMOTO¹ (1.Graduate School of Science and Engineering, Ehime University)

We applied an improved gravity inversion technique by Bear et al. (1995) to rapidly invert Bouguer gravity data in Kanto District, Japan, for a 3-D density distribution as a source of the observed field. The technique estimates the density distribution within the source volume using a least-squares inverse solution that is obtained iteratively by singular value decomposition using orthogonal decomposition of matrices with sequential Householder transformations. The source volume is subdivided into a series of right rectangular prisms of specified size but of unknown density. This discretization allows the construction of a system of linear equations relating the observed gravity field to the unknown density distribution. Convergence of the solution to the system is tightly controlled by a damping parameter which may be varied at each iteration. Application to a gravity data set from Kanto District, Japan, has yielded a geologically reasonable result that agrees with published models derived from interpretation of gravity, magnetic, seismic, and drilling data.