Time dependent modeling of magma intrusion during the early stage of the 2000 Miyakejima activity

The high-frequency GPS analysis at Miyakejima volcano captured rapid deformation following the early stage of Miyakejima 2000 activity. Given a specified dike and spherical source geometry, we solve the opening distribution on each sub-dike that minimizes a linear combination of the norm of the weighted data residual and roughness of the opening distribution. The time dependence of dike intrusion and spherical source deflation shows that magma migrated laterally from the southern region to the west coast. Although the depth of the maximum opening does not change with time, a very shallow intrusion can be seen at the eastern part of the dike. This may explain why cracks and graben structures developed on the west coast. Most of the magma migrated northwest, with only a fraction coming to the surface in an eruption below sea level.