We request funds to image crustal structure below Mt. Fuji, Japan, to constrain the geometry of the magma storage system and volcano plumbing. Mt. Fuji is currently being monitored by Japanese collaborators and has an extensive seismic data set accumulated over the last 20 years. Seismicity and active volcanism is particularly intense in the Mt. Fuji region, providing an excellent data set with ample data coverage. We will address the question of deep versus shallow magma storage regions, the presence of partial melt accumulation in the crust and the geometry of magma conduits. Established methods of three-dimensional seismic imaging will be used to illuminate the conduit/magma storage areas using physical parameters such as seismic velocity, attenuation, anisotropy and hypocenter correlation. High resolution event locations will constrain magma transport models near in the magma storage region. Fluid dynamical properties constraining magma and gas flux in the conduits will be modeled using non-linear processes relating harmonic tremor to constricted flow. Deep, low frequency events observed below Mt. Fuji will be modeled by moment tensor inversion for correlation to structural features delineated by seismic imaging.
This proposal addresses issues of magma storage in subduction zone settings. Estimation of deep melt accumulation and transport is essential for analysis of volcano formation and evolution. Structural analysis of active volcanic systems provides the framework for assessment of eruption dynamics and hazard mitigation.
