Salton Trough Fault
The new Salton Trough Fault, which runs parallel to the San Andreas Fault, could impact the earthquake-prone region that includes the greater LA area, seismologists say. It is in an area where a swarm of nearly 200 small earthquakes hit last week, raising concerns they might trigger a larger earthquake on the southern San Andreas Fault.

Researchers have revealed a newly discovered fault line running parallel to the San Andreas fault in Southern California.

The new Salton Trough Fault, which runs parallel to the San Andreas Fault, could impact current seismic hazard models in the earthquake-prone region that includes the greater Los Angeles area, seismologists say.

The newly identified strike-slip fault within the Salton Sea, just west of the San Andreas Fault, is in an area where a swarm of nearly 200 small earthquakes hit last week, raising concerns they might trigger a larger earthquake on the southern San Andreas Fault.


To aid in accurately assessing seismic hazard and reducing risk in a tectonically active region, it is crucial to correctly identify and locate faults before earthquakes happen,' said Valerie Sahakian, a Scripps alumna, and lead author of the study.

The research team used a suite of instruments, including multi-channel seismic data, ocean-bottom seismometers, and light detection and ranging, or lidar, to precisely map the deformation within the various sediment layers in and around the sea's bottom.

They imaged the newly identified strike-slip fault within the Salton Sea, just west of the San Andreas Fault.

'The location of the fault in the eastern Salton Sea has made imaging it difficult and there is no associated small seismic events, which is why the fault was not detected earlier,' said Scripps geologist Neal Driscoll, the lead principal investigator of the NSF-funded project, and coauthor of the study.

'We employed the marine seismic equipment to define the deformation patterns beneath the sea that constrained the location of the fault.'

Mapping of earthquake faults provides important information for earthquake rupture and ground-shaking models, which helps protect lives and reduce property loss from these natural hazards.