Integration of InSAR and GNSS Data to Monitor Volcanic Activity of Sakurajima Calderas, Japan: from Small Displacement Measurements to Geophysical Modeling

Abstract

Sakurajima volcano is one of the most active volcanoes in Japan and caused the most powerful eruption in Japan in the last century (1914). Volcanic eruptions are often preceded by ground deformations. The activity of Sakurajima volcano is monitored through interferometric analysis of SAR data, ALOS Palsar-2 and Sentinel-1, to obtain caldera displacements over the observed period, from 2015 to 2019 and to investigate deformations correlated with inflation and deflation cycles of magma plumbing system, eruptions and diking. Time series are calibrated and validated through GEONET stations of the Geospatial Information Authority of Japan and the global navigation satellite System (GNSS) stations of the Sakurajima Volcano Research Centre. SAR and GPS information are used to identify the most dramatic events affecting the active Sakurajima area since 2015, specifically a dyke intrusion and the ongoing volcanic activity, characterized by several eruptive episodes.