The Response of Repetitive Very‐Long‐Period Seismic Signals at Aso Volcano to Periodic Loading

Abstract

Tidal and hydrological loading has been shown to modulate volcanic eruption over semidiurnal to seasonal periodicities (Dzurisin, 1980; Hamilton, 1973; Mason et al., 2004; Mauk & Johnston, 1973; McNutt & Beavan, 1987; Sottili & Palladino, 2012). Earthquake-induced dynamic stress changes, on the other hand, suggest the possibility of a more imminent change in eruption activities due to seismic waves of a much shorter period (seconds to minutes) (Hill et al., 2002; Linde & Sacks, 1998; Manga & Brodsky, 2006; Namiki et al., 2019). As volcanic eruptions are generally not frequent, attention has been paid to exploring how seismic activities near the volcanic plumbing system are triggered or modulated by these external loadings. Since seismic signals detected near the volcanic plumbing system reflect the internal dynamics (Blake, 1981; Sturtevant et al., 1996; Tait et al., 1989), variations of the overpressure or/and the rheology of conduit and country rock, it is critical to understand and validate how seismic activities are triggered/ modulated by external loadings.