Monday, October 25, 2010

Shakey Quakey

One of the fun things about beach walking in Santa Monica--and life in Los Angeles in general--is that The Big One could occur at any time.

The 6.7 earthquake a few days ago, Oct. 21, in the Gulf of California near La Paz and Cabo San Lucas, is a reminder of this fact. If you draw a line from the fault this quake occurred on, it goes north to about where the San Andreas Fault ends.

The Pacific plate is grinding north against the North American plate, and currently the movement is occurring right about on this continuing line.

Today there was a much smaller quake near Bakersfield, not far from the Tejon Pass, site of the biggest earthquake in California since records were kept.

That earlier Big One was in 1857 on the southern half of the San Andreas with ground rupture visible from near Parkfield CA down to Wrightwood (not far from San Bernardino). It was magnitude 7.9.

Here's the info on it:

http://earthquake.usgs.gov/earthquakes/states/events/1857_01_09.php

The only buildings around at that time were Fort Tejon, some houses in Gorman, and a few ranches. Only one person died in that quake--when an adobe in Gorman collapsed.

Quakes have occurred on the southern section of the San Andreas fault about every 150 years, so we are due for another movement any time now.

This morning's 3.7 quake occurred in a field near Mettler CA on Highway 99 south of Bakersfield, 20 miles north of the San Andreas. Here's the info on it:

http://neic.usgs.gov/neis/recent/ci10826277_l.html

From the Santa Monica beach to Bakersfield to Palm Springs, we will all have front row seats for the next time the Pacific plate moves five or ten yards north against the continental US.

The 6.7 Gulf of California quake on Oct. 21 occurred at 11:53 am--an hour and a half after The Great California Shake Out at 10:21. This earthquake drill was the third widespread duck-and-cover exercise in California--the first two just in SoCal but this one observed throughout the state.

The shift in Baja California was almost in sync with the scheduled drill. Good vibrations.

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