Seismic structure of the subducting seamounts on the trench axis: Erimo Seamount and Daiichi-Kashima Seamount, northern and southern ends of the Japan Trench

摘要

We present detailed P-wave velocity models of subducting seamounts from two wide-angle seismic experiments across the Erimo Seamount and Daiichi-Kashima Seamount, northern and southern ends of the Japan Trench. Common characteristics of the velocity models of the seamounts are that the maximum crustal thicknesses of the seamounts are 12–17 km thicker than a typical oceanic crust and that P_n velocities beneath the seamounts are approximately 7.7 km/s, i.e., slower then those of the neighboring area. These features are very similar to the crustal models for the seamounts produced by the Cretaceous off-ridge volcanism on the Pacific Basin.