California mega-earthquake fear: Is the San Andreas fault at risk of the 'Big One'?

New research suggests that a newly discovered 'structure' in the San Andreas fault line could result in a massive earthquake, often referred to as the "big one."

The geological study, written up in the journal Lithosphere, details that there is a 15- to 20-mile-long stretch of the San Andreas fault ‒ called the Durmid ladder structure ‒ that could result in an earthquake with a magnitude of 7 or greater.

The research put the odds at 75 percent that it would occur in both northern and southern California sometime over the next 30 years.


"This newly identified Durmid ladder structure is a voluminous, right-reverse fault zone that broadens across Durmid Hill around rotating domains of regularly spaced, left- and right-lateral cross faults," a research article on the study reads.

The research was performed by Susanne Jänecke, Daniel Markowski, James Evans, Patricia Persaud and Miles Kenney.

The potential cause of a magnitude 7 or greater earthquake is the result of what is known as "slow earthquakes" or slow-slip events (SSEs) that go unnoticed by humans.

"Temporary episodes of creep acceleration, known as slow-slip events (SSEs), have been interpreted as earthquake precursors and as a possible triggering factor for major earthquakes," researchers Mostafa Khoshmanesh and Manoochehr Shirzaei wrote in a paper published in Nature, obtained by The Daily Mail.

The Durmid ladder structure is located in the Durmid Hill region of southern California, an area that is highly faulted and between 0.6 and 2.5 miles wide. It has a broken ladderlike look to it, hence its name.


If an earthquake were to occur and both the Durmid ladder structure and the San Andreas Fault collapsed, it would be felt across an area of 15 square miles, though the exact effects are difficult to accurately predict due to the size and shape of both structures.

However, the research does give some parameters of where devastation might be likely to occur.

"The East Shoreline fault appears to continue northward for over 100 km past the Mecca and Indio Hills along the northeast margin of Coachella Valley, where southwest-dipping basin-fill deposits are being exhumed on its northeast side," the study reads. "Lines 4 and 5 of the Salton Seismic Imaging Project imaged faults that are along strike of the East Shoreline fault and occupy the same structural position as the East Shoreline fault relative to the San Andreas fault."

The "big one" has been warned about several times before, with the U.S. Geological Survey writing extensively on the topic, including how to use past earthquakes to better predict the future.

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