Helmholtz Centre Potsdam
GFZ German Research Centre for Geosciences
Abstract (EDOC: 15227)
We examine the P-wave velocity structure beneath the island of Hawaii using P-wave residuals from teleseismic earthquakes recorded by the Hawaiian Volcano Observatory seismic network. The station geometry and distribution of events makes it possible to image the velocity structure between y40 and 100 km depth with a lateral resolution of y15 km and a vertical resolution of y30 km. For depths between 40 and 80 km, P-wave velocities are up to 5 per cent slower in a broad elongated region trending SE–NW that underlies the island between the two lines defined by the volcanic loci. No direct correlation between the magnitude of the lithospheric anomaly and the current level of volcanic activity is apparent, but the slow region is broadened at y19.8uN and narrow beneath Kilauea. In the case of the oceanic lithosphere beneath Hawaii, slow seismic velocities are likely to be related to magma transport from the top of the melting zone at the base of the lithosphere to the surface. Thermal modelling shows that the broad elongated low-velocity zone cannot be explained in terms of conductive heating by one primary conduit per volcano but that more complicated melt pathways must exist.
(2001): P-wave velocity structure of the uppermost mantle beneath Hawaii from traveltime tomography. Geophysical Journal International, 146, 3, 594-606.