SUBSIDENCE OF THE COLLAPSED CALDERA OF MIYAKEJIMA, 2006-2011

摘要

Ground deformation of Miyakejima, Japan, between2006 and 2011 was investigated from Synthetic ApertureRadar images to gain insights into the mechanics of postcalderadeformation associated with the 2000 eruption.70 and 69 interferograms were created from 22 ascendingand 21 descending images, respectively, of PALSARboarded on the ALOS satelitte. Our result reveals a localizedvertical subsidence of up to 150 mm/yr aroundthe collapsed summit. The observed displacement fieldis well modeled by a closing sill at 0.5 km below the surface.The compaction volume is too small to be consistentwith the amount of sulfur dioxide emission. The modeledsill would thus represent the compaction of the conduitcolumn associated with the summit collapse, rather thanthe gas emission.