Los Angeles

New Earthquake Study Takes a Closer Look at Grapevine Area North of LA

The research found earthquakes happen in the area known as the Grapevine on average every 100 years

A new study looks at the potential for a major earthquake along a stretch of the San Andreas Fault north of Los Angeles, site of one of the most powerful quakes ever recorded in the United States.

The U.S. Geological Survey research found earthquakes happen in the area known as the Grapevine on average every 100 years. The last major temblor occurred 160 years ago, rupturing 185 miles of the San Andreas fault.

The land on either side of the fault has been pushing against the other at a rate of more than 1 inch a year since 1857, the researchers said. That accumulating energy will be suddenly released in a major earthquake, when the land along the fault would move by many feet, according to the study.

"So you expect that amount of accumulation of energy will be released in the future in a large-magnitude rupture, somewhere along the San Andreas," lead author of the study, USGS research geologist Kate Scharer, told The Los Angeles Times

A repeat of the 1857 earthquake could damage aqueducts that ferry water into Southern California from the north, disrupt electric transmission lines and tear up the 5 Freeway, where the Grapevine section runs on top of the San Andreas fault at Tejon Pass, The Times reported. It is a major north-south trucking route through California's Central Valley.

Central Los Angeles could experience a couple of minutes of shaking, according to the study. The 1994 Northridge earthquake shook for roughly 15 seconds.

"This would be more broadly felt across the basin," Scharer told The Times. "It would impact our ability to be a world-class city."

Scientists observing trenches at this site discovered that earthquakes on this section of the San Andreas fault occurred on average once every 100 years, according to The Times. The 1857 quake, which occurred on Jan. 9, was centered about 45 miles northeast of San Luis Obispo.

Two deaths were reported in connection with the quake, which occurred at a time when the area was more sparsely populated, according to Caltech. The area of greatest shaking now includes the communities of Wrightwood, Frazier Park, Taft and Palmdale.

NBC4's Jonathan Lloyd contributed to this report.

Copyright CNS - City News Service
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