Investigation of the Distinct Seismic Characteristics in the Southwestern Ryukyu and the Northern Manila Subduction Zone

Great earthquakes mostly generate on plate interface of subduction zones. Furthermore, greatsubduction zone earthquakes sometimes generate tsunamis and cause nature hazards, such as Chile(1960), Alaska (1964), and Japan (2011). Taiwan is located in the edge of the Pacific Oceanseismic zone, the Ryukyu subduction zone in the north and the Manila subduction zone in the south.Seismic and tsunami hazard in Taiwan need to be considering. Especially several nuclear powerplants locate in north and south of Taiwan. Seismicity distribution shows significant spatialvariation in the northern Manila and the southwestern Ryukyu subduction zone. Historically, morethan 10 earthquakes (Mw > 7) have been observed in the southwestern Ryukyu subduction zone. Incontrary, there are less dense seismicity and no large earthquake greater than Mw7 has beenobserved in the northern Manila subduction zone. Previous studies have shown some parametersvarying along the trench may influence seismogenic behaviors and mechanical properties on theplate interface. Including the age of subducting slab, slab angle, seafloor roughness, and plateconvergence rate. Thus, in this study, we discuss plate coupling, the status of interaction betweensubducting and overriding plates, and using other geophysical data (such as seismic profile、gravityand GPS) to evaluate the potential of occurrence of large earthquakes in these two subductionzones.