Magma Chamber Detected Beneath an Arc Volcano With Full‐Waveform Inversion of Active‐Source Seismic Data

Arc volcanoes are underlain by complex systems of molten-rock reservoirs ranging from melt-poor mush zones to melt-rich magma chambers. Petrological and satellite data indicate that eruptible chambers form in the topmost few kilometres crust. However, very have ever been definitively located, suggesting most too short-lived or small be imaged, which has direct implications for hazard assessment modeling differentiation. Here we use a high-resolution technology based on inverting full seismic waveforms image small, high-melt-fraction chamber was not detected with standard tomography. The melt reservoir extends ∼2 at least 4 km below sea level (b.s.l.) Kolumbo—a submarine volcano near Santorini, Greece. coincides termination point recent earthquake swarms may missing link between deeper high-temperature hydrothermal system venting crater floor. poses serious as it could produce highly explosive, tsunamigenic eruption future. Our results suggest similar (relatively but high-melt-fraction) gone undetected other active volcanoes, challenging existing forecasts reactive-flow models