Borrego Sun - Since 1949

The earthquakes in California's San Andreas Fault, are caused by the gravitational pull of the sun and the moon, according to a new study printed in Proceedings of the National Academy of Sciences.

Led by Nicholas J. van der Elst, a seismologist from the U.S. Geological Survey and other colleagues, the scientists have long wondered if the gravitational pull of the sun and moon could trigger earthquakes on Earth.

They discovered that the low-frequency earthquakes could occur when the fortnightly tide, which is the two-week tidal cycles, is rapidly increasing in size and not when it is at its peak, as might be expected.

Van der Elst explained that the moon, when it's pulling in the same direction the fault is falling, causes the fault to slip more --- and faster. He added that the finding demonstrates the weakness of the fault.

Yolandi Jooste

Moonrise at Fonts Point, July 19

Scientists believe that human-created changes effecting the Salton Sea, appear to be the reason why California's massive 'Big One' earthquake is more than 100 years overdue and building up for the greatest disaster ever to hit Los Angeles and Southern California. Researchers found that strands of the San Andreas Fault under the 45-mile long rift lake have generated at least five 7.0 or larger quakes about every 180 years.

David Shelly, a seismologist from USGS said that ---using the new findings--- if all of a sudden, they saw that the deep part of the fault was slipping a huge amount; it might suggest that there was an increased chance of having an earthquake at the shallower part of the fault.