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By Roz Rogoff

About this blog: In January 2002 I started writing my own online "newspaper" titled "The San Ramon Observer." I reported on City Council meetings and other happenings in San Ramon. I tried to be objective in my coverage of meetings and events, and...  (More)

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If an earthquake happened here

Uploaded: Mar 27, 2011
We've all seen the devastating videos from Japan. Not all of Japan is destroyed, but several cities in the north are in rubble. The Japanese were prepared for an earthquake. The building requirements there are higher than ours, and their disaster planning was in place. What they didn't prepare for was everything happening at once or the severity of the earthquake and it's numerous and ongoing aftershocks.

If those weren't bad enough, and they were bad, the tsunami wiped out entire cities, removing almost all habitable shelter. Now the threat of nuclear meltdown from nearby nuclear power plants is looming.

Fortunately that wouldn't happen here, but I wondered what potential disasters, earthquakes, floods, mud slides, tsunamis, could happen to us or near us that would impact our lives and safety.

The East Bay is unique because all of the cities in Contra Costa County and Alameda County (except Oakland) are covered by a regional communication system to connect all fire, police, and emergency workers in both counties by radio and cell phone. This is one of Mayor Abram Wilson's proudest accomplishments.

The City of San Ramon has been preparing for an emergency or potential emergencies for the last ten years and ramped up emergency preparedness in the last five years. The City's website has a whole section devoted to Emergency Preparedness.

Last week I interviewed Ray Riordan, City Emergency Preparedness Manager, about what residents might expect from an earthquake in this region, and what we could do to be prepared. Riordan explained that different kinds of faults cause different kinds of damage. The fault that caused the tsunami in Japan is a subduction fault where one plate dives under another.

Faults along the San Francisco coastline and inland are slip faults, which are not as severe as the subduction faults that caused the earthquakes in Japan and Chili. Slip faults do not create the huge underwater waves, so there's no chance of them causing a tsunami. However, there are subduction faults further north along the coast. So if you have friends or relatives in Seattle or Portland, they might be in danger from a tsunami after an earthquake.

The bad news for us is that the U.S. Geological Survey (USGS) [predicts a 63 percent chance http://earthquake.usgs.gov/regional/nca/ucerf/ that an earthquake of magnitude 6.7 or greater will occur in the San Francisco bay area by 2036. The probability map shows the Hayward fault with a 31 percent probability estimate and the San Andreas fault at 21 percent.

A major earthquake on either of those would cause considerable local damage, but might not be as serious in San Ramon as the Calaveras fault. The North Calaveras fault lies almost directly underneath our section of I-680 and could produce a quake as high as 6.7. There is a 7% chance of an earthquake on the Calaveras fault in the next 25 years.

The other nearby fault is the Mount Diablo Thrust Fault, which is the fault that created the mountain millions of years ago. It could cause a lot of damage in Dougherty Valley but the projection for an earthquake there is less than 1 percent. So don't lose any sleep over it.

The Hayward fault is probably the biggest threat to the East Bay and the Bay area. It is about 20 miles from San Ramon and 40 miles from the water supply in the delta. Zone 7 uses water from the delta to supply Dougherty Valley, Dublin, Livermore, and Pleasanton. The rest of San Ramon and Danville get water from East MUD, which would not be interrupted even if water from the delta is not available.

Still Riordan recommends keeping at least a week's supply of food and water in an accessible place, like the garage or car, where you can get to it easily. Be sure to include enough for all family members and pets. Be Ready San Ramon Valley lists supplies to have on hand for up to six months of being on your own. Riordan says everyone should store at least one week of food and water, and we should plan to be on our own for a minimum of three days.

After a quake City Inspectors will check each home for damage and tag as green (OK), yellow (needs some repairs before moving back), or red (unsafe). Until your house is inspected or accepted to move back in, homeowners can camp out in their yards. The golf courses are also designated for tents in an emergency, and San Ramon has a temporary emergency shelter just for pets.

The San Ramon Valley Fire Protection District provides training for the Community Emergency Response Team. CERT teams are made up of people who live in our neighborhoods who are trained to help out in emergencies. You will recognize CERT volunteers by their green vests and helmets. They will be able to provide help during the immediate aftermath of an earthquake or other natural disaster.
What is it worth to you?


Posted by Roz Rogoff, the San Ramon Observer,
on Mar 31, 2011 at 4:01 pm

Roz Rogoff is a registered user.

One of my links didn't convert properly, so I'm re-entering it here. I hope it will work this time.

[Web Link that an earthquake of magnitude 6.7 or greater] could happen here in the next 25 years.

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