9316012 Chen, W-P This research is a continuation of investigation of the mechanical state of the subducted lithosphere and its interaction with the surrounding mantle. Deep earthquakes in subduction zones of Izu-Bonin, Japan, and Ryukyu-Kyushu arcs have been numerous recently and have high-quality broad-band seismic recordings. This research involves precise determination of the rupture processes for approximately 35 large to moderate-sized events deeper than 100 km in these zones. The work will also involve investigation of the patterns of travel-time residuals and anomalies in pulse- width/amplitude of body waves from these events. The results will bear on questions of the origin of deep earthquakes and the depth of penetration of the subducted slab. ***