Seismic detection and tracking of avalanches and slush flows on Mt. Fuji, Japan

Abstract. Avalanches are often released at the dormant stratovolcano Mt. Fuji, which is the highest mountain of Japan (3776 m a.s.l.). These avalanches exhibit different flow types, from typical dry-snow avalanches in winter to slush flows triggered by heavy rainfall in late winter to early spring. Avalanches from different flanks represent a major natural hazard as they can reach large dimensions with run-out distances up to four kilometres, regularly destroy parts of the forest and sometimes damage infrastructure. For monitoring the volcanic activity of Mt. Fuji, a permanent and dense seismic network is installed around the volcano. The small distance between the seismic sensors and the volcano flank ( −1 to 50.6 m s −1 are consistent with the numerically predicted speeds. In addition, we deduced two scaling-relationships based on seismic parameters to quantify the size of the mass flow events. Our results are indispensable for assessing avalanche risk in the Mt. Fuji region as seismic records are often the only available dataset for this natural hazard. The approach presented here can be applied in the development of an early-detection and location system of avalanches based on seismic sensors.