Automatic onsite imaging of volcanic ash particles with VOLCAT: Towards quasi-real-time eruption style monitoring

Abstract

Detecting transitions between different eruption styles through real-time monitoring can mitigate the risk posed by volcanic hazards. During periods of eruptive activity, changes in ash characteristics can reflect changes in magma behavior in the conduit. However, conventional methods for characterizing ash involve manual field processes followed by laboratory observations, which leads to a potential lag between a change in eruption style and the time at which the change is detected. We have developed the Visual Observation Laboratory Capturing Ash Transition (VOLCAT), a new field-based instrument for automatic onsite microphotograph imaging of ash particles with minimum interval of one hour during periods of ongoing volcanic activity. The VOLCAT successfully captured microphotographs of ash particles during eruptions at Shinmoedake and Sakurajima, and helped rapid characterization of the ash particles. The rapid characterization of ash particles using the VOLCAT will allow quasi-real-time evaluation of eruption style during periods of ongoing activity.