姶良カルデラ周辺の地盤変動に関する有限要素法モデルを用いた圧力源形状の検討（続報）

Abstract

We calculated the ground deformation due to a polyhedron pressure source resembling the geometry of the low S-wave velocity region beneath the Aira caldera, using a FEM model. This model is considered to be more compatible with recent seismological findings than conventional models such as the Mogi model. Calculated displacements are consistent with GPS and leveling survey observations as well as would be expected from the Mogi model. The area of crustal deformation is narrower when the pressure source has a vertical shape. On the other hand, the estimated magma supply to the Aira caldera, using the polyhedral pressure source model, is 10-20% larger than that assuming the Mogi model.