2025/06/05 by Cheng-Hung Chen, Cheng‐Hung Chen, J. Bruce H. Shyu
Earth and Planetary Sciences · #earthquake and tectonic studies #Geological and Geophysical Studies #Seismic Waves and Analysis
paper · pdf · doi:10.1785/0120250009
ABSTRACT Taiwan is an active orogenic belt characterized by numerous active structures and frequent earthquake activities. As a result, identifying the locations and seismic potential of these structures is essential for minimizing earthquake-related damages. Although a comprehensive on-land seismogenic structure database for the island has been constructed by the Taiwan Earthquake Model project team, and the database has already been widely used for disaster preparedness work, a similar database for offshore structures is lacking. With an integration of available geological and geophysical data, we identified 54 offshore structures across six neotectonic domains around Taiwan using two criteria that faulting in seismic reflection profiles disturbs the seabed, and structural lineaments on the seafloor need to be continuous. Subsurface geometries of the faults were reconstructed based on their cross-cutting relationships and the seismogenic depth data from previous studies, and we applied three regression equations to estimate the potential earthquake magnitude of the structures. The results show that these structures are capable of generating earthquakes exceeding magnitude 6.5, and some specific multifault rupture scenarios could produce earthquakes greater than magnitude 8.0. With future updates when new data becomes available, this offshore seismogenic structure database would significantly improve earthquake hazard assessments and marine resource management studies in Taiwan.