Seismotectonic characteristics of the Taiwan collision-Manila subduction transition: The effect of pre-existing structures
Journal
Journal of Asian Earth Sciences
Journal Volume
173
Pages
113-120
Date Issued
2019
Author(s)
Abstract
Based on the distribution of an earthquake swarm determined from an ocean bottom seismometer (OBS) network deployed from 20 August to 5 September 2015 in the northernmost part of the South China Sea (SCS) and data from inland seismic stations in Taiwan, we resolved a M L 4.1 earthquake occurring on 1 September 2015 as a NE-SW-trending left-lateral strike-slip event that ruptured along the pre-existing normal faults generated during the SCS opening phases. The direction of the T-axes derived from the M L 4.1 earthquake and the background seismicity off SW Taiwan present high consistency, indicating a stable dominant NW-SE tensional stress for the subducted Eurasian Plate (EUP). The distinct stress variations on the two sides of these reactivated NE-SW trending features suggest that the presence of pre-existing normal faults and other related processes may lessen the lateral resistance between the Taiwan collision and Manila subduction system, and facilitate the slab-pull process for the subducting portion, which may explain the NW-SE tensional stress environment near the transition boundary in the northernmost part of the SCS. © 2019 Elsevier Ltd
Subjects
collision zone; earthquake swarm; Eurasian plate; normal fault; passive margin; seismograph; seismotectonics; strike-slip fault; subduction; Manila; National Capital Region; Philippines; Taiwan
Publisher
Elsevier Ltd
Type
journal article