抄録
Travel times and apparent velocities are measured for fifty-three Ryukyu-Taiwan-Philippine Earthquakes recorded at the Wakayama Microearthquake Observatory. Very sharp reflections from 650km discontinuity at distance range 15°-20° are found. A velocity model is given by these data. The model has two discontinuities—one is at the depth of 420km and the other of 670km. The latter is very sharp and of 10 percent velocity increase, and the former is not so sharp.
