NEHRP Clearinghouse
- Title
- Evaluation of Tsunami Risk to Southern California Cities.
- File
- PB2005101782.pdf
- Author(s)
- Legg, M. R.; Borrero, J. C.; Synolakis, C. E.
- Source
- January 2003, 68 p.
- Identifying Number(s)
- PF-2002-11
- Abstract
- Locally-generated tsunamis from major active faults offshore southern California threaten the nearby coastal cities. Disruption of operations at important port facilities due to tsunami attack could severely impact regional and nationwide economies. Historically, potential for tsunami generation from local sources has been considered insignificant because most of the faulting in the southern California region is strike-slip in character. Yet, major thrust and reverse faulting occurs throughout the western Transverse Ranges (WTR) including historical tsunami occurrence following strong earthquakes in the Santa Barbara Channel region and west of Point Conception. Furthermore, the major strike-slip faults offshore southern California, south of the WTR, have sinuous traces with many bends and step-overs. Local tectonic convergence at restraining bends and step-overs creates folding and seafloor uplift whereas local tectonic divergence at releasing bends and step-overs produces extension and seafloor subsidence. Rapid seafloor deformation at these fault bends and offsets may generate local tsunamis that could be damaging to nearby coastal areas. This project examines a large seafloor uplift, the Santa Catalina Island platform, and its potential for generating destructive local tsunami that attack the southern California coastal area near metropolitan Los Angeles.
- Keywords
- Risk assessment; Coasts; Tectonics; California; Coastal areas; Risks; Deformation; Sea floors; Ocean bottoms; Computer models; Tsunamis; Metropolitan areas; Seafloor lift; Faults (Geologic); Earthquakes