Tuesday, July 29, 2008

Whittier Earthquake hits SoCal, July 29. I feel the earth. Move. Under my Feet.

los angeles earthquake july 29 whittierDear god.  Yes, I'm sitting here wearing my pith helmet and the animals are hiding under the bed.

5.8 quake hit Chino Hills/Diamond Bar.  11:42 am.  29 miles SE of Los Angeles. (CalTech saying it's 5.4 - they won't all agree on the size for a few hours).

It was a shallow earthquake, which unlike deep ones, send out wider shocks.  The quake was felt through out Los Angeles and Long Beach.  

It snuck up on you, then rattled, then rolled.  It rolled for a good while, an estimated 30-40 seconds.

There was also a 3.1 earthquake in Barstow this morning around 5 am.

This could be the prologue to a larger quake, as that is the history of the Whittier fault.

The Whittier Fault is a geologic fault that is a branch of the Elsinore Fault Zone in Southern California.

The Whittier Fault is a 40 kilometer (24 mile) right-lateral strike-slip fault that runs from Chino Hills, California to Whittier, California. It is part of the bigger Puente Hills Fault, which stretches from west of downtown Los Angeles to the Puente Hills area. The fault has a slip rate of between 2.5 and 3.0 millimeters/year (0.09 - 0.11 in/yr). It is estimated that this fault could generate a quake of MW6.0 - 7.2 on the moment magnitude scale.

In 1987, the Whittier Narrows earthquake sequence occurred with two large earthquakes, a 5.9 and a 5.3, happening within 3 days. No surface rupture happened during the quake but there has been surface rupture on this fault within the last 10,000 years. The fault caused $350 million in damages, killed 8 people and 9,000 people were displaced.

Pictured left, a news photo from the 1987 quake in Whittier.

There have been no injuries or structural damages reported today as of yet.  Verizon did report that many of it's cel phone towers in Chino Hills are down, affecting some cel phone usage.  There was also a land slide off the 91 freeway near Green River.

If your phone isn't working, that is generally because EVERYONE picked up their land line or cel phone at the same time.

Today, there were 12 after-shocks felt between 1.3 - 3.6 in the first hour after the initial quake and more are expected.

Shallow earthquakes tend to generate a large amount of after shocks. So don't climb up on any ladders!

The first earthquake attributed to the Whittier Fault and felt strongly in the Whittier area was an earthquake July 8, 1929 at 8:45am with an estimated magnitude of 4.7. It was believed to be located (felt strongest) in the area of East Whittier, which had ($50,000-$350,000) damage. It was also felt very strongly in the Los Nietos/Santa Fe Springs area where (4) people were injured.

The next strong quake in the Whittier area was on the evening of June 15, 1967 centered East of Whittier. It had a magnitude of 4.1 and was felt as a rolling quake throughout much of the LA basin and parts of Orange County, knocking objects from shelves and causing minor damage. It may have been centered in the Puente Hills, possibly North of La Habra.

The next large earthquake on the Whittier Fault occured on Jan. 1, 1976 at 9:20 am with a magnitude of 4.2. It was centered in the Puente Hills of Los Angeles County and caused damage in the Whittier area.

Pictured, in my pith helmet.  Laugh all you want, but most injuries are from things falling on your head.  My mom brought this back from her safari in Africa years ago, and it's hard as a rock.  It's out 24/7 on a wall hook for easy access.

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