A Comprehensive 3D Seismic Velocity Model for the Eastern Taiwan-Southernmost Ryukyu regions

We describe the construction of a 3D seismic velocity model that may serve as a reference for geophysical investigations in eastern Taiwan, where the westernmost Ryukyu subduction zone connects to the active arc-continent collision zone. For offshore region where local tomography is not available, we construct the model by integrating multiple geophysical data sources in order to characterize, in geometry as well as in velocity, the different structures existing in the area. The multiple data sources used to create the offshore model mainly consist of seismic reflection and refraction data to identify crustal structures and a global hypocenter dataset to define the subduction geometry. The offshore velocity model is then combined with a local onland tomography model in order to create the new 3D P-velocity model. The structures distinguished in this work include the water layer, sedimentary units (e.g., forearc basins and accretionary prism), the oceanic crustal basement of the Philippine Sea plate, the thickened crust of the Luzon Arc, the subducted Philippine Sea slab, and the curved Ryukyu margin. This investigation results in the first comprehensive Vp velocity model for the region and covers the area from 121.0 - 124.4°E and 22.0 - 25.3°N, with its depth reaching 120 km.

並列關鍵字

3D velocity model ； Westernmost Ryukyu subduction zone ； Taiwan

國際替代計量

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