Tracing Volcanic Activity Chronology from a Multiparameter Dataset at Shinmoedake Volcano (Kirishima), Japan

Abstract

Routine volcano monitoring increasingly involves multiparameter datasets. Databases that include multi-disciplinary datasets have great potential to contribute to the evaluation of ongoing volcanic eruptions and unrest events. Here, we examine the characteristics of a multiparameter dataset from Shinmoedake volcano (Kirishima) in Japan for the period of 2010–2018 to examine how the chronology of volcanic activity can be traced. Our dataset consists of global navigation satellite system (GNSS), seismic, tilt, infrasound, sulfur dioxide (SO₂) column amount, and video records. We focus mainly on the period after 2012, particularly a series of ash emissions in 2017 (hereafter the 2017 eruption), lava effusion, and Vulcanian eruptions in 2018 (hereafter the 2018 eruption). Our dataset shows that the GNSS observations successfully captured the gradual inflation of the volcano edifice, suggesting magma intrusion or pressure buildup in the magma storage region prior to the 2017 and 2018 eruptions. The number of volcanic earthquakes also gradually increased from 2016 toward the eruptions, particularly events occurring beneath Shinmoedake. Tilt data captured a precursor tilt event prior to the 2017 eruption and a magma chamber deflation during the lava effusion of the 2018 eruption. Tilt, seismic, infrasound, SO₂ gas column, and video data record signals accompanying periodic degassing during the lava effusion and explosive degassing accompanying the Vulcanian eruptions, which have similar characteristics to those reported for past eruptions at Shinmoedake and other volcanoes. This similarity suggests that multidisciplinary databases will be an important reference for future evaluations of ongoing volcanic activity and unrest.