A recent study by a research team from the Deep-Sea Science and Engineering Institute of the Chinese Academy of Sciences, along with 中山 University, China University of Petroleum (East China), and the University of Barcelona, Spain, has revealed renewed activity along a subsea fault zone in the northern South China Sea—the Continental Slope Fault Zone. Their findings were published online in Marine and Petroleum Geology.
Seismic activities along submarine faults are not only the triggers of earthquakes but also capable of triggering seabed landslides, which could cascade into catastrophic events such as tsunamis. The spatial distribution, structural features, and recent activities of active faults in the seafloor are critical parameters in assessing marine geological disasters.
This study employed high-resolution multichannel seismic data, gravity and magnetic data, and seafloor topographic data to systematically investigate the active tectonics in the deepwater area of the northern South China Sea. The research team revealed the spatial distribution, structural features, and recent activities of the continental slope fault zone (CSFZ). The results indicate that the CSFZ is an active fault zone with a length of approximately 1100 km and a NE-E strike, developed near the shelf-slope break. The CSFZ (southeastern Qiongdong section) exhibits a normal-oblique fault structure in both map and cross-sectional views. Fault displacement analysis and growth index suggest that the CSFZ (southeastern Qiongdong section) has experienced multiple activations since the late Quaternary. Combined with the present-day seafloor geomorphic features, it is suggested that the CSFZ is likely to experience further activities in the future, potentially triggering a chain of seafloor earthquake-landslide-tsunami hazards, posing a significant geological hazard risk.
The study elucidates the specific distribution, geometrical structures, and recent activities of the continental slope fault zone in the northern South China Sea, providing foundational data for geological hazard assessments in Chinese waters.
This research was supported by the National Key Research and Development Program of China, the National Natural Science Foundation of China, and the Guangdong Provincial Innovation and Entrepreneurship Team Program for High-Level Talents.
The related article can be found at: https://doi.org/10.1016/j.marpetgeo.2024.106777
