Coronavirus Information for the UC San Diego Community

Our leaders are working closely with federal and state officials to ensure your ongoing safety at the university. Stay up to date with the latest developments. Learn more.

Geophysical evidence for a San Andreas subparallel transtensional fault along the northeastern shore of the Salton Sea

TitleGeophysical evidence for a San Andreas subparallel transtensional fault along the northeastern shore of the Salton Sea
Publication TypeJournal Article
Year of Publication2016
AuthorsSahakian V., Kell A., Harding A., Driscoll N., Kent G.
JournalBulletin of the Seismological Society of America
Date Published2016/10
Type of ArticleArticle
ISBN Number0037-1106
Accession NumberWOS:000388365100005
Keywordsbaja-california; earthquake; extension; geometry; ground-motion; history; lake tahoe basin; pull-apart basins; slip rates; southern-california

The southern San Andreas fault (SSAF) accommodates a significant amount of strain between the Pacific and North American plates; thus, the fault represents a major geohazard to the populated areas of southern California, in particular the larger Los Angeles metropolitan area. Paleoseismic chronology of ruptures along the SSAF segment suggests this fault is near the end of its interseismic period (similar to 180 years), because it has not ruptured in historic times (similar to 320 years). A recent active-source seismic experiment performed in the Salton Sea west of the SSAF provides evidence for extensional deformation along the northeastern shore of the Salton Sea. This study posits that the extensional deformation is due to a previously unmapped fault, here named the Salton trough fault (STF). The seismic reflection data image a divergent sediment package that dips toward the northeast with thicknesses up to at least 2 km. Refraction inversion produces a southwestward-dipping velocity discontinuity that crops out east of the SSAF surface trace, consistent with the existence of a southwest to northeast gradient in lithology. If present, the existence of the STF has scientific and societal relevance. First, the STF appears to control the recent Salton trough architecture north of Bombay Beach. Second, from a seismological hazards perspective, the presence of this structure could alter the current understanding of stress transfer and rupture dynamics in the region, as well as community fault models and ground-motion simulations on the SSAF.

Student Publication: