The big one
A look back at one of the most deadly earthquakes in California history and a few tips encourage you to get prepared for another eventual disaster.
The ShakeOut, which is Thursday, Sept. 15, began in California in 2008 and has grown into an international program. We know we are prone to large earthquakes, we just don’t know when — so preparation is key to dealing with the disaster when it comes. The first lesson in preparation is “Drop, Cover and Hold on,” but here are a few other things to prepare for:
- Learn to use a fire extinguisher
- Put together an emergency supplies kit
- Know how to shut off utilities
- Establish local and out-of-area emergency contacts
- Participate in first-aid classes or community response team trainings
GAS: If you smell gas or hear a blowing or hissing noise, open a window and get everyone out quickly. Turn off the gas using the outside main valve, if you can, and call the gas company from a neighbor’s home.
Caution: If you turn off the gas for any reason, a qualified professional must turn it back on. NEVER attempt to turn the gas back on yourself.
WATER: Water quickly becomes a precious resource following many disasters. It is vital that all household members learn how to shut off the water at the main house valve.
ELECTRICITY: Locate you electrical circuit box. For your safety, always shut off all the individual circuits before shutting off the main circuit.
Forget about the doorway
Over the years, methods of safety during an earthquake have changed and you might need to update your plan. More tips at ShakeOut.org.
Things to do around the home
Ask yourself: If the residence began shaking, what would topple and how should I secure it?
1. Garage: Strap water heater to wall. If water heater falls during quake, it could cause a fire or you could lose an emergency water source. Store caustic and flammable liquids such as gas cans, paint thinners and weed killers in lower, childproof cabinets. Know how to manually open electric garage doors.
2. Kitchen: Prevent injuries and damage from falling plates and kitchenware by installing childproof locks on upper cabinet doors. Keep a fire extinguisher on hand.
3. Dining room: Secure decorative pieces with floral clay or museum wax. Install locks on cabinet doors.
4. Living room: Secure large paintings and bookshelves to walls. Secure TV.
5. Bedrooms: Move beds if they are under windows. Do not hang paintings or other heavy objects over headboard. Make sure ceiling fan is securely bolted to a rafter. If an earthquake hits while you’re in bed, stay there and cover head with a pillow.
6. Bathroom: Store flammable items like nail polish on lower shelves. After a quake, fill tubs and sinks with water for emergencies, especially if you have to leave without your pets.
7. Gas meter: Reduce the risk of a gas leak by installing an automatic shut-off valve.
8. Attic: If you have an attic fan, brace it.
A few quake facts and myths
The largest recorded earthquake in the United States was a magnitude 9.2 that struck Prince William Sound, Alaska on March 28, 1964.
The largest recorded earthquake in the world was a magnitude 9.5 in Chile on May 22, 1960.
Earthquakes can still claim a large number of lives. Historically, floods, droughts and epidemics dominated disaster deaths, a high annual death toll in recent years often results from a major earthquake and possibly a tsunami caused by them. Since 2000, the peak year in annual death toll was 2004. The Sumatra earthquake and tsunami of 2004 was magnitude 9.1, and 230,000 people died across 14 countries.
It is estimated that there are 500,000 detectable earthquakes in the world each year. 100,000 of those can be felt, and 100 of them cause damage.
Each year the Southern California area has about 10,000 earthquakes. Most of them are so small that they are not felt. Only several hundred are greater than magnitude 3.0, and only about 15-20 are greater than magnitude 4.0.
According to the U.S. Geological Survey, there is no such thing as “earthquake weather.” Statistically, there is an equal distribution of earthquakes in cold weather, hot weather, rainy weather, etc. If weather does affect earthquake occurrence, it is not yet understand how it works.
Pinnacles, California Offset by San Andreas Fault
The present-day location of The Pinnacles is 195 miles from the volcano that the San Andreas sliced it from. The volcanic rocks are 23 million years old. That means the San Andreas fault has moved 0.59 inches per on average per year over the last 23 million years.
The San Andreas Fault is not a single, continuous fault, but rather is actually a fault zone made up of many segments. Movement may occur along any of the many fault segments along the zone at any time. The fault system is more than 800 miles long, and in some spots it is 10 miles deep.
During the 1906 San Francisco earthquake, the San Andreas Fault ruptured horizontally across roughly 296 to 300 miles. The surface offsets averaged around 10 to 20 feet.
Deadly October quake
On Oct. 17, 1989, a segment of the San Andreas Fault 11 miles beneath Loma Prieta peak in the Santa Cruz mountains, ruptured. Geologists later said the fault there slipped as much as 7 feet.
The resulting magnitude 6.9 earthquake shook for only 15 seconds, but it was enough to knock ABC’s World Series video feed off the air for several minutes while Al Michaels described the earthquake. There were no major injuries to the 62,000 fans at Candlestick Park. The stadium had minor damage in only two seat sections, and the Series resumed 10 days later.
A region devastated
Some of the worst damage was to two key bridges.
A 76-by-50-foot portion of the upper deck of the Bay Bridge collapsed onto the lower deck. Several cars were smashed, but only one motorist was killed.
Across the bay in West Oakland, a 1.25-mile stretch of the Cypress Street Viaduct carrying Interstate 880 pancaked, instantly crushing 41 people.
Bystanders and first responders made heroic efforts to pull other victims from the rubble. One man was rescued after spending 90 hours in his car beneath the concrete. He died a month later.
Particularly hard hit was San Francisco’s Marina District. Shock waves rolling through the mud and sand used to fill in the shallow water there turned into slush. This amplified the waves at the surface, toppling homes and businesses.
In total, 63 people were killed and 3,757 injured. More than 28,000 structures were damaged — a property loss of $6 billion to $10 billion.
Sources: California Department of Insurance, California Earthquake Authority, USGS, Southern California Earthquake Center, ShakeOut.org, California Department of Conservation