Slab temperature and thickness from seismic tomography

Abstract

Delay times of compressional body wave phases from both teleseismic and local events are used to invert for a high-resolution P wave velocity model in the Tonga subduction zone. Using only null-space components to modify the minimumnorm solution, an enhanced model is obtained which has been biased toward the theoretical solution but has the same data misfit as the minimum-norm solution. The final image shows a very narrow and continuous slab with maximum velocity anomalies of the order of 6–7%; many of the gaps within the slab, as well as artifacts around the slab which were present in the minimum-norm solution, are absent in the biased image.