Thursday, March 25, 2021

Southern Part Of San Andreas Moving Faster Than Previously Thought

The southern part of the San Andreas fault is moving a lot faster than previously thought and has therefore the highest likelihood for a major earthquake

As if the San Andreas fault wasn’t worrying enough… A new scientific paper reveals that a small stretch of the southern San Andreas Fault is moving much faster than previously thought.This anomalous place is called the Mission Creek strand and stretches from around Indio, through Desert Hot Springs and into the mountains of San Bernardino.

This particular strand of the San Andreas failure has been interpreted to be not very active. It’s actually very active and is the fastest slipping fault for the San Andreas in Southern California. Therefore it has the highest likelihood of a large magnitude earthquake to occur on it in the future,” said the lead author of the study.

Higher slip rates on faults mean more risk. It means stress is accumulating faster on that fault and you would need basically either more earthquakes or larger earthquakes over centuries to relieve that stress,” said Morgan Page, one of the developers of the California Earthquake Uniform Forecast.

All of which means that this particular strand on the San Andreas has a greater risk than was previously understood. How much of an additional risk? It needs to be assessed.

Any infrastructure in that area, like water or gas lines which run over the fault itself, will need to be looked at with a critical eye, given that offsets of as much as 30 feet could occur in the event of a major quake.

Their study is in a region where the San Andreas fault is quite complex. This is a substantial step in improving our understanding of how the Southern San Andreas fault works,” said Sally McGill, a geology professor at Cal State San Bernardino.

Regardless of what happens on the Mission Creek strand, we know that sizable earthquakes on the San Andreas are possible.

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