Fire damage in post-quake San Francisco, 1906

With hundreds of quakes shaking Brawley at the southern tip of the San Andreas fault, it’s time to take a closer look at ‘The Big One,’ the 7.8 earthquake scientists say is overdue by geological stopwatches. Such major quakes strike SoCal every 45-144 years. It’s been 155 years since the last one.

Will Los Angeles survive the fires that will inevitably follow a 7.8 San Andreas earthquake, or burn to the ground as San Francisco did in 1906? 90% of the total destruction in the great San Francisco earthquake of 1906 was caused by fire. Over 30 major blazes, many caused by ruptured gas mains, destroyed 25,000 buildings in 490 city blocks. In all, the fires burned for four days and nights.

San Francisco’s 1906 building codes cannot compare to today’s, and Los Angeles is not packed with similar wooden structures. But scientist say San Francisco’s devastation was nothing compared to what is likely to happen here: an estimated 1600 fires that will follow a 7.8 quake.

At the peak of a massive series of firestorms in October 2007, 17 major blazes were burning simultaneously. A half-million acres were consumed, 14 people died, a million were evacuated. The 6.7-magnitude 1984 Northridge earthquake triggered 110 fires. Seismologists estimate a 7.8 quake is likely to cause sixteen times more fire damage.

How well prepared is Los Angeles to deal with the firestorm?

• Lucy Jones | U.S. Geological Survey and Caltech, chief scientist on The Great Southern California ShakeOut
• Capt. Mario Rueva | Chief of Emergency Services, Los Angeles Fire Department
• Jim McDaniel | Senior Assistant General Manager, L.A. Department of Water & Power

How significantly will a 7.8 earthquake impact Greater Los Angeles?

Lucy Jones: “We conservatively estimate 1,800 deaths, 50,000 injuries and $200 billion in damage and other losses.

“The freeways that cross the fault will be reduced to rubble, and our other lifelines — railways, power lines, and aqueducts — will fare no better.

“Five 11- to 20-story steel-frame buildings collapse completely, and one percent (45,000) of lesser structures are total losses, with one in 25 wood-framed houses and apartment buildings suffering significant damage. If Santa Ana winds fan the 1,600 blazes started by car crashes and downed power lines, an estimated 133,000 single-family homes are likely to be destroyed.

“Of those 1600 fires, 1200 will grow beyond the capabilities of a single engine company, some growing to super-conflagration status. 3-million square feet of building stock is forecast to go up in smoke.”

Have we ever seen fires like those expected in the wake of the “Big One?”

Capt. Mario Rueva: “The Wilshire Devon Fire in Westwood in 1989 burned over 33 structures across an eight block area. It was the largest structure fire in L.A. history with a property loss of over $20-million. That single fire tied up 30% of Los Angeles’ firefighting resources.

Lucy Jones: “Mutual aid will not offer much assistance. Compare to what happened in the Northridge quake which led to 110 fires. We’ll have 13 million victims and we’ll need help from the Bay Area and Arizona at a time when I-10 and I-15 have been cut.”

How stable will LA’s water system be following a quake, especially given the DWP’s aging infrastructure?

Jim McDaniel: “Hydrants and drinking water are on the same system, but bursting pipes still fall within normal parameters for a system this size.”

Lucy Jones: “A significant portion of DWP’s water pipes will fail and it will take an estimated 6 months to repair the system during earthquake recovery.”

Capt. Mario Rueva: “It’s mostly a gravity-fed system that doesn’t rely on electric pumps that could fail, but the pipes are old and in a major disaster we may not be relying on that system for water. It is a significant logistical problem.”

Where will we get the water we need to fight thousands of fires? What about the ocean?

Lucy Jones: “Vancouver has a backup system in place drawing seawater through pumps on backup generators. San Francisco has had a seawater-cistern system in place since 1906. It was refurbished by then-mayor Feinstein and used in the Loma Prieta quake. Oakland installed one after 1906, but has let it deteriorate.”

Capt. Mario Rueva: “Vancouver has a far smaller municipal footprint. Their system may not be workable here, but it’s being studied.”

Jim McDaniel: “Los Angeles is blessed with multiple supplies from the Owens Valley to the Colorado River in addition to groundwater resources. It’s unlikely all would be cut off.”

Fuel for a major firestorm won’t be limited to flammable materials on the surface.

Lucy Jones: “Underground pipelines are cradled by the earth and are protected to some degree, but all bets are off when liquefaction turns soil into quicksand — not to mention hundreds of faults crossing countless pipelines under the L.A. Basin.

“There are hundreds of miles of underground pipelines carrying everything from natural gas to gasoline and hydrogen. One system alone carrying crude oil has 26 miles of pipes running under Los Angeles, with 110-thousand-barrel-a day capacity.”

· In 1976, a front-loader hit an 8” gasoline pipeline during construction on Venice Boulevard in Culver City. Nine people were killed, some burned to death in their cars, 15 were hospitalized. 16,000 gallons of gasoline poured from the pipeline, running between Standard’s El Segundo refinery and its Van Nuys distribution terminal.

· In 1989, a pipeline that carries fuel between Las Vegas and Los Angeles, exploded in a fireball that killed three people, injured 31, sending a geyser of gasoline 200 to 300 feet in the air in a San Bernardino residential area, which then ignited and exploded.

· The 6.7-magnitude Northridge quake of 1994 and 110 resulting fires was nothing compared to a major San Andreas event with a fault 800 miles long compared to Northridge’s 10-mile fault length.

· There’s a 6-month supply of water in reservoirs west of the San Andreas Fault, if those reservoirs are full. LA has many reservoirs and though some are no longer suitable as drinking water given new rules regarding open reservoir storage, they can be used for firefighting.