Tomographic image of P‐velocity structure beneath Kilauea's East Rift Zone and South Flank: Seismic evidence for a deep magma body

Abstract

We present first results from the analysis of P‐wave arrival time data recorded from November 11 to December 31, 1999, by a temporary 29‐station network installed across Kilauea Volcano's East Rift Zone (ERZ) and South Flank (SF) on Hawaii, augmented by data from the permanent network of the Hawaiian Volcano Observatory. Starting with the inversion result for a minimum 1D velocity model, we use arrival time data from 135 local earthquakes to invert for the 3D P‐velocity structure. The resulting tomographic image shows evidence for a deep magma body beneath the ERZ just east of its southward bend, and a smaller magma body at about 5 km depth beneath the WNW‐ESE trending segment of the ERZ. We also observe a drastic change in velocities south of the Hilina fault system from velocities around 5.5 km/s in the west to 6.5 km/s to the east.