California

Researchers Are Dropping Earthquake Sensors Into the Ocean to Learn More About an Off-Shore Fault

The seismometers will detect ground motion along a 90-mile stretch of ocean floor

Earthquake researchers will drop seismometers along a 90-mile stretch of ocean floor this month to get a better idea of the potential hazards of offshore fault systems.

The Scripps Institution of Oceanography will place the underwater seismometers along the northern section of a fault called the San Diego Trough. The five seismometers, which work by detecting and recording motion in the ground, will be left on the ocean floor for three months.

When compared to faults on land, like the well-known San Andreas fault, there is less research around off-shore faults like the San Diego Trough, which stretches as far north as Santa Catalina Island.

"They can be very, very small -- magnitude 1, 1.5, that you don't see with the current equipment that we have on land," Scripps seismologist Gabi Laske told KPCC

The study could provide a springboard for research into other faults, like the Newport-Inglewood Fault, Laske told KPCC. The fault starts in Culver City and stretches into the ocean.

In March 1933, a magnitude-6.4 earthquake occurred in the fault zone, resulting in 120 fatalities and more than $50 million in property damage.

In a previous study of off-shore faults, Caltech researchers dropped seismometers about 300 miles off the coast of California.

"A large earthquake on any one of these offshore faults in the continental shelf region could cause very strong ground shaking in the coastal areas along any coast of Southern California," Kohler told KPCC.

Click here to read the full KPCC report.

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