Runup of landslide-generated tsunamis controlled by paleogeography and sea-level change
Qiliang Sun, Qing Wang, Fengyan Shi, Tiago M. Alves, Shu Gao, Xinong Xie, Shiguo Wu, Jiabiao Li
Abstract
Abstract Pre-Holocene landslides and tsunami deposits are commonly observed on continental margins and oceanic islands. However, scarce evidence has thus far linked pre-historic submarine landslides to particular tsunami events. This work focuses on an 839 km 3 submarine landslide that occurred in the South China Sea at 0.54 Ma. Bathymetric restorations show that the paleoshoreline at 0.54 Ma was 180–580 km to the south of its present-day location. In such a setting, the tsunami triggered by the landslide at 0.54 Ma was able to generate larger waves with shorter arrive times when compared to an equivalent landslide-generated tsunami under present-day conditions. This observation proves that tsunamis generated by submarine landslides during sea-level lowstands caused catastrophic damage to the South China Sea coast in the past, and so will do in future sea-level lowstands. This study stresses the importance of restoring paleoshorelines for detailed analysis of historic landslide-generated tsunamis.