A Comprehensive 3D Seismic Velocity Model for the Eastern Taiwan-Southernmost Ryukyu regions
Other Title
台灣東部與琉球弧溝系統最南地區的三維速度模式
Journal
Terrestrial, Atmospheric and Oceanic Sciences
Journal Volume
14
Journal Issue
2
Pages
159-182
Date Issued
2003
Author(s)
Abstract
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-conti nent 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 dif ferent structures existing in the area. The multiple data sources used to create the offshore model mainly consist of seismic reflection and refrac tion data to identify crustal structures and a global hypocenter dataset to define the subduction geometry. The offshore velocity model is then com bined 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 Phi lippine 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 121.0-124.4E and 22.0-25.30N, with its depth reaching 120 km.
Publisher
中華民國地球科學學會
Type
journal article