Three Dimensional Images of the Kamchatka-Pacific Plate Cusp

Abstract

First arrivals of seismic waves were recorded along the Kamchatka arc using broadband seismic stations deployed for one year in 1998–1999. Cross correlation methods were used from a high resolution data set for tomographic inversion of body waves. The P‑wave teleseismic tomography shows evidence of slab shoaling along the northern terminus of the Kamchatka subduction zone. Tomographic anomalies corroborate trends in seismicity, geochemistry, heat flow, shear wave splitting, and surface wave inversions. Thermal ablation via contact with asthe‑nosphere, under the proper conditions, is offered as a possible explanation of the observed shoaling of the Kamchatka slab edge.