Subsurface magma movement inferred from extensometer and tiltmeter records during the early stage of the 2018 Shinmoe-dake eruptions, Japan

Abstract We infer the temporal changes in pressure sources that induced crustal deformation during 2018 Shinmoe-dake eruption using strain and tilt observations discern deep magmatic activity associated with early stage of this began approximately 19 h earlier than previously defined onset activity. Distinct were observed from around 09:00 on 6 March to 12:00 8 (JST), coincident lava outflow into crater dome formation. Existing studies have attributed change deflation a spherical source located at ~ 7 km bsl (below sea level) northwest Shinmoe-dake. Here we examine data acquired Kirishima volcanic group, find distinct measured Isa-Yoshimatsu Observatory 14:00 5 March. This can be explained by source, thereby suggesting magma ascent was thought. The time variation is estimated time-dependent inversion Ensemble Kalman Filter; ascended 11 Phase 1 (14:00 06:00 March) descended 2 (06:00 March). Interferometric synthetic aperture radar analysis suggests dike intrusion had occurred just below until March, inflatable emplacement residual fluids 2011 eruption. It also known surface eruptive increased 1, including an increase ash venting night These observations, therefore, suggest reservoir followed due large supply surface. Graphical