| Popis: |
Phreatic and phreatomagmatic eruptions are difficult to predict with accuracy on volcanoes due to complex interactions at depth between heat, water, and magmatic fluids. To better understand such multifaceted interactions, we present here a multidisciplinary geophysical approach performed on Miyakejima, a 10-km wide stratovolcano in the Izu Bonin arc. Its plumbing system was highlighted by combining four geophysical methods: magnetotellurics, seismicity (hypocenters), self-potential, and thermal image (remote sensing). We thus propose the first large-scale interpretation of the volcanic structure in terms of rock properties, temperature, fluid content, and fluid flow. Our findings indicate that hot volatiles released from a deep magmatic reservoir (> 350°C, 2.5–4.5 km depth) rise through a narrow permeable path, interact with the conductive hydrothermal system beneath the 2000 A.D. caldera ( |
