Investigating the 3D velocity structure beneath the northern Taiwan by joint inversion of local and teleseismic P-wave data
Abstract
Northern Taiwan has experienced a tectonic transition from collision to extension, where the northward subduction of Philippine Sea plate and the subsequent back-arc opening of Okinawa trough create active volcanism in this region at different stages, such as Tatun volcano group and offshore Kueishan volcanic Island. Especially, more than 7 million people living at capital Taipei near the Tatun volcano group, and thus whether the volcano group is active or not has long been a central debate. Recently, emerging evidences have indicated the existence of deep magma reservoirs beneath the Taipei metropolis and Kueishan volcanic Island from S-wave shadows and P-wave delays (Lin 2016; Lin et al., 2018). To examine such deep structure, we combine the local P-wave arrival time data from Central Weather Bureau (CWB) and the teleseismic waveform data from a new island-wide Formosa Array Project to conduct a 3D joint inversion. Benefit from the teleseismic data and the dense station distribution of the Formosa Array, we improve the model resolution primarily at 50-100-km depth in northwestern portion of northern Taiwan. The results showed enhanced low velocity anomalies beneath the Tatun volcano group and the Kueishan Island, roughly consistent with the location of the magma reservoirs proposed. The new 3-D tomographic imaging therefore provides better illumination of deep melt- and subduction-related structure beneath the northern Taiwan
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.S21H0604W
- Keywords:
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- 7299 General or miscellaneous;
- SEISMOLOGY