Science & Technology



July 4th earthquake won't delay the Big One. And it might have worsened quake strain

Rong-Gong Lin Ii, Los Angeles Times on

Published in Science & Technology News

A: For instance, in the 75 years before the great 1906 earthquake that destroyed much of San Francisco in shaking and flames, there were 14 earthquakes of magnitude 6 or greater in the Bay Area, Stein has previously said in an interview. (Since the 1906 quake -- a magnitude 7.8 -- there have been only three.)

Angelenos might remember what is now known as the earthquake storm of the 1980s and '90s. As tallied by Caltech seismologist Egill Hauksson, it began with the Whittier Narrows temblor in 1987 (magnitude 5.9), which killed eight, followed by Pasadena in 1988 (4.9); Montebello in 1989 (4.4); Upland in 1990 (5.2); Sierra Madre in 1991 (5.8), which killed a woman; and ended with Northridge in 1994, which killed at least 57 people.

The 1800s were also an active time for earthquakes in California.

In 1800, a magnitude 7.2 quake hit on the San Jacinto fault east of Temecula. Then, in 1812, the San Andreas and San Jacinto faults moved in a magnitude 7.5 earthquake through present-day cities such as San Bernardino, Rialto, Loma Linda, Yucaipa and Highland and brought down Mission San Juan Capistrano's Great Stone Church, killing more than 40 people inside. Then, in 1857, the southern San Andreas sent extreme shaking on both sides of the fault all the way from Monterey County to Los Angeles and San Bernardino counties in a breathtaking magnitude 7.8 quake.

Q: What's an example of a moderate quake actually coming before something far worse?

A: On March 9, 2011, a magnitude 7.3 earthquake off the east coast of Japan led some people to be complacent when, two days later, a historic magnitude 9 earthquake struck. Some people ignored protocol and failed to immediately evacuate before the catastrophic tsunami hit.

Closer to home, the main shock of the last truly great earthquake in Southern California -- at 8:24 a.m. on Jan. 9, 1857 -- was preceded an hour earlier in the Monterey County area by a magnitude 5.6 earthquake, and a magnitude 6.1 earthquake an hour before that.

Q: What can we do to prepare?

A: In general:

If you're an owner of an older home or building, retrofit it if it needs it, and if you rent, ask the landlord about it.


Stock up on food, water and medicine to be self-sufficient for two weeks.

Plan for your workplace to have a continuity plan. The Los Angeles County Economic Development Corporation has a template on how to do it at

And keep an eagle eye wherever you live or work, and imagine all the possible things that could fall on yourself, your loved ones and pets. Head to your hardware store's earthquake prep section to find ways to bolt bookcases down and keep large objects from falling on you when the shaking comes.

We have a comprehensive list of tips available in our article, "Get ready for a major quake. What to do before -- and during -- a big one," at

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