Potential earthquake-triggered landslides near Palos Verdes and implications for near-field tsunami early warning

Jingchuan Wang, Shane Zhang, & Allen L. Husker

Submitted August 30, 2026, SCEC Contribution #15261, 2026 SCEC Annual Meeting Poster #TBD

Steep coastal topography and seafloor relief, inherently weak bedrock units, and seismic activity in the Southern California Borderland create favorable conditions for major landslides capable of generating local tsunamis. Active landslides along the Palos Verdes Peninsula are recognized hazards that require continued monitoring, and offshore slopes have also long been identified as a candidate location of large submarine landslides. The Palos Verdes fault, which extends across the southwestern Los Angeles Basin and adjacent offshore region, is considered capable of hosting magnitude 7 earthquakes. Here, we investigate earthquake-triggered landslides using simulated ground motions from a Mw7.05 scenario earthquake on the Palos Verdes fault. We apply the Newmark sliding block method and map the spatial prediction of both onshore and submarine landslide displacements across the Palos Verdes Peninsula and its offshore margin. The results indicate that an M7 earthquake could produce localized permanent displacements over 10 m and mobilize hundreds of millions of cubic meters of landslide material. We then simulate tsunami generation and propagation due to co-seismic seafloor deformation and both onshore and offshore landslides. For the specific Mw7.05 rupture scenario considered here, landslide-triggered waves pose a greater coastal hazard than the earthquake-generated tsunami alone, owing to the predominantly strike-slip fault geometry and the large volume of sliding material. The subsequent tsunamis will primarily impact the Peninsula and the adjacent Santa Monica and San Pedro Bays where modeled wave heights reach as high as 3 m and could threaten coastal communities and infrastructure. Future establishment of offshore dense arrays, including distributed acoustic sensing that connects Los Angeles and Santa Catalina Island, could support near-field tsunami early warning with lead times of a few minutes.

Citation
Wang, J., Zhang, S., & Husker, A. L. (2026, 08). Potential earthquake-triggered landslides near Palos Verdes and implications for near-field tsunami early warning. Poster Presentation at 2026 SCEC Annual Meeting.

Related Projects & Working Groups
Seismology