Central Portion of San Andreas Fault is Likely to Host Powerful Earthquakes

According to a recent study, the center portion of the San Andreas Fault may be capable of producing greater earthquakes than previously thought.

Aseismic creep occurs between Parkfield and Hollister on the famed California fault. Instead of creating major quakes by suddenly releasing stress, the two sections of the fault move unnoticeably, allowing stress to dissipate.  

Earthquakes in the Middle Section of San Andreas Fault 

Researchers have discovered that this area of the fault may have undergone earthquakes of magnitude 7 million years ago and more. This is more powerful than the 1989 Loma Prieta earthquake that killed 63 people in San Francisco, as per Live Science. 

According to earthquake scientist Genevieve Coffey of GNS Science in New Zealand, it's impossible to know exactly how long ago the huge quakes on the fault happened.  At Live Science, Coffey said the centre area should be taken into consideration for earthquake threat. 

The San Andreas Fault consists of three parts. The magnitude-7.9 Fort Tejon quake, for example, displaced the land along the fault 29.5 feet (9 meters) in 1857. 

The northern section of the fault stretches from Hollister, California, to Cape Mendocino, California, and includes the San Francisco Bay area. The 1906 San Francisco earthquake, which had an estimated magnitude of 7.9, occurred on this fault. 

However, the fault hasn't produced any earthquakes larger than magnitude 6 between Parkfield and Hollister. A 2,000-year search for evidence of recent major earthquakes has yielded no results, according to geoscientists who dug down the fault. 

Also Read: Section of San Andreas Fault Line May be More Disastrous Than Previously Believed

Exploring San Andreas Fault 

If the central San Andreas fails to build up enough stress to trigger a big earthquake, it could serve as a conduit for quakes from the northern or southern sections of the fault, according to Coffey. Her coworkers and she aspired to travel more than 2,000 years in the past. 

That's why scientists exploited the fact that heat is generated when a defect slips because of the friction it creates. Coffey described it as like rubbing your hands together.

According to The Washington Post, more than 1,800 degrees Fahrenheit of heat can be generated in the fault by this process (1,000 degrees Celsius). As a result of these temperature variations, organic molecules accumulating in sediments might undergo structural modifications.

Can San Andreas Fault be Visible at the Surface? 

Plates are travelling past each other at a rate similar to how fast the fingernails grow each year. Nonetheless, the typical motion is not a steady one. As they push against one another, the plates will be locked for years, with no movement at all. 

As a result of the sudden release of tension, the plates suddenly slip a few feet. Earthquakes are caused by waves propagating outward from the point where the rock is cracking. 

The San Andreas fault may be clearly seen in numerous places, such as the Carrizo Plain (San Luis Obispo County) and the Olema Trough (Marin County). In some locations, the fault has been covered in alluvium or overgrown with bush because it hasn't moved in a long time.

Many of the highways along the fault in San Bernardino and Los Angeles Counties pass through mountains of gouge, the powdery, crushed rock that has been pulverized by the shifting plates. 

Related Article: Aseismic Creep Surfaces Shaking Discovery in California's Fault

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