Temporal variations of plume activities before the 8 October 2016 eruption of Aso volcano, Japan, detected by ground-based and satellite measurements

Abstract

Abstract At many volcano observatories, measurements of the plume height are frequently applied. On the other hand, the recent development of the satellite measurements enables the monitoring of the SO2 mass emitted by the passive degassing at sufficient temporal resolution. Using these two techniques, this study focuses on the degassing activity before the 8 October 2016 phreatomagmatic eruption of Aso volcano, Japan. Here we show the temporal variations of the plume height, the SO2 mass, and ground-based SO2 flux during 6 months before the eruption. Our result shows similar temporal changes of them, especially for the maxima and the increase, respectively, in about 2 months and 6 days before the eruption. This result indicates that the degassing system had been stable during the whole study period, but the accumulation of volcanic gas in the conduit since August might trigger the phreatomagmatic eruption. These techniques can be sufficient to monitor the degassing activity and to detect its precursory change.

Keywords

• Aso volcano
• Volcanic eruption
• Monitoring camera
• Volcanic plume
• Plume height
• SO2