Title of Project:
Integrative studies on the geodynamics of the Philippine and Taiwan arc systems
Name of Principal Investigator：
Center for Environmental Studies, National Central University
1. Located in the northern end of the Manila Trench, the deformation front off SW Taiwan is considered to be associated with the rifting of the South China Sea and is a potential area of generating great earthquakes and tsunamis. On February 10, 2017, an Mw5.3 earthquake occurred in the offshore area of Tainan, which provides us a good opportunity to understand the seismogenic structures of that area. We have immediately deployed 5 ocean bottom seismometers (OBSs) covering the mainshock-source area from 13 February to 1 March to record the aftershock data. All the OBSs were successfully recovered. We analyze the recorded data together with the Central Weather Bureau data. By using the 3D velocity model to improve aftershock locations, we found that the aftershocks spatially located in a narrow seismogenic structure.
2. Previous studies have shown that the Mindoro-Panay Orogeny started in the early of Miocene (about 20-16 Ma ago) and ended in Pliocene. However, we found that 10-12 Ma igneous events from diorites, andesites and river sands and 44-42 Ma gabbros and plagiogranites in the western Panay Island, while the 30 Ma diabases and granites were identified in the eastern Panay Island. Because the late ignition was about 12 Ma ago and the age of the rock samples in the Mindoro was 6-7 Ma, we suggest that Mindoro-Panay Orogeny has started in the Late Miocene and is still active.
3. Our research group and our collaborators from the University of the Philippines joined together the AOGS-EGU Conference on Natural Hazards in Asia in early February 2018. Our team presented four papers on our recent results on the natural hazards in Asia, and the Philippine team presented two papers. These results all have received rigorous discussion and attention. This activity not only put forward our research progress to the two international organizations, but also significantly broadened the images of both geoscience community of Taiwan and the Taiwan-Philippines collaboration project.