This research is to study the attenuation and velocity structure of back-arc regions using teleseismic body waves and the effects of shallow structure on earthquake body waveforms. The deep structure beneath spreading centers in the back-arc provides important constraints on the dynamics of the spreading process. Attenuation and velocity anomalies in the vicinity of the rift will be measured by comparing sS and sScS phases with direct S and ScS waveforms which have similar paths through the lower mantle to the receiver. The effect of near-source bathymetric and structural complexities will also be investigated.
