Expected losses from a future California earthquake are rising

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Frail first-story buildings collapsed on cars during the 1994 Northridge earthquake. (US Geological Survey)

The projected annual cost of earthquake damage to California is rising sharply amid an increase in property values ​​and a better understanding of how softer soils cause greater damage during shaking.

New estimates show that California is expected to lose an average of $9.6 billion annually in earthquake damage. That’s a 157% increase from the latest estimate, in 2017, when the price was $3.7 billion annually, according to a new report from the USGS and FEMA.

“In any year, there’s a major earthquake…you can easily expect $100 billion in damage,” Kishore Jaiswal, a research structural engineer with the USGS, Kishore Jaiswal, the principal investigator on the report, told The Times.

The aggregate figures confirm how much older buildings have risen in value in recent years, but remain vulnerable to serious damage or collapse in the next big earthquake.

It’s also a sobering reminder of the seismic toll facing California. After the state’s other major earthquakes—1906 in San Francisco, 1933 in Long Beach, 1989 in the Greater San Francisco Bay Area and 1994 in Northridge—it took years, if not decades, for cities to recover, and enormous costs had to be taken. It is paid not only by governments and insurance companies, but also by individuals who are never supplemented.

According to the new report, Los Angeles and Orange counties share the highest rate of any metro area in the country, with a combined projected average annual loss of $3.3 billion annually. In second place is the San Francisco-Oakland-Berkeley metro area, with a projected loss of $1.8 billion annually.

Earthquakes cost California about 65% of the nation’s annual earthquake cost, which is $14.7 billion a year.

Projected average annual earthquake losses for other areas of California include $1.3 billion for Riverside and San Bernardino counties, $917 million for the San Jose-Sunnyvale-Santa Clara metro area, $285 million for San Diego County and $220 million for Ventura County.

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Assuming that projections of annual earthquake losses remain the same, over the course of three decades, California is expected to lose $288 billion in earthquake damage. This number is consistent with recent earthquake scenarios, such as the magnitude 7.8 earthquake on the southern San Andreas fault or the magnitude 7 earthquake on the Hayward fault.

Of that total, Southern California’s five counties — Los Angeles, Orange, Riverside, San Bernardino, and Ventura counties — stand to lose nearly $150 billion. The nine-county San Francisco Bay Area will lose nearly $90 billion.

“It’s a sobering reminder of why we need to prepare for those rare but large earthquakes, where only one major event can overcome the costs of more frequent but smaller events,” USGS director David Applegate said in a statement.

The report’s authors calculated “annual” seismic losses to calculate the average cost of earthquake damage on an annual basis.

It’s similar to how car insurance companies calculate the premiums people pay annually: People may have a collision once every few years, but insurance companies calculate an annual bill for drivers that takes into account the projected average annual cost of a future collision. The amount of the annual car insurance premium can vary, depending on factors such as the driver’s age, accident history, and the type of vehicle being driven.

The 6.7-magnitude earthquake that struck Northridge in 1994 caused up to $20 billion in damage and more than $40 billion in economic losses, “making it the costliest earthquake disaster in U.S. history,” according to the California Geological Survey.

And the damage from this earthquake, which had its epicenter in the outskirts of the San Fernando Valley, pales in comparison to the devastation that would be caused by a large earthquake centered beneath older neighborhoods, such as downtown Los Angeles.

The magnitude of the 1994 earthquake was relatively mild. By contrast, a magnitude 7.8 earthquake would produce 45 times more energy, and no such earthquake has struck Southern California since 1857 and Northern California since 1906.

The last earthquake in the world with a magnitude of 7.8 struck in February, which vigorously shook Turkey and Syria. More than 50,000 people died.

A large portion of California’s buildings constructed in the 20th century are susceptible to earthquake damage or collapse. Its retrofitting would now make cities more resilient – keeping people alive, homes intact, workplaces and neighborhoods functioning.

Experts say rising real estate values ​​in the country may enable some owners to use the equity they’ve collected to fund retrofits. Retrofitting can now cost much less than repairing severe damage after an earthquake, which would have damaged a building so much that it might need to be replaced.

Some cities in California have required property owners to retrofit certain types of buildings at risk. A law passed in Los Angeles in 2015 mandating the reinforcement of flimsy apartment buildings with first floors—often used for cars—resulting in more than 8,700 out of 12,400 retrofits. That’s a 70% completion rate. An analysis estimated that at least $1.3 billion was spent on those retrofits.

FEMA and state officials made grants available for retrofits. Homeowners in certain ZIP codes in Los Angeles, Pasadena, San Francisco, Oakland, and Berkeley can apply for retrofit grants of up to $13,000 through the end of May to enhance “soft-storey homes,” where extra-heavy living space is built over a garage that is prone to collapse in case An earthquake.

“This study reinforces the nation’s need to be proactive about making communities safer from threats like earthquakes,” FEMA Deputy Director Eric Hooks said in a statement. “This includes adopting the latest seismic building codes and investing in earthquake-resistant projects.”

But many other cities in California have not acted to request the retrofits. Even in Los Angeles, city officials have yet to address potential seismic hazards for older steel-frame high-rise buildings built before the 1994 Northridge earthquake. The USGS said it was plausible that five steel-frame buildings in the South California is in a hypothetical 7.8-magnitude earthquake on the San Andreas Fault, and 10 of them could be so damaged that it would not be safe for occupation.

Some cities are still lagging behind. Much of the Inland Empire, which covers Riverside and San Bernardino counties, still has many older brick buildings that haven’t been updated—among the structures most at risk from the earthquake. It can crumble, not only killing the occupants of the buildings but also raining projectiles onto nearby sidewalks, parking lots and roads, throwing remnants of brick walls with such force that it can crush cars and buses.

In the 6.9 magnitude Loma Prieta earthquake of 1989, a brick wall in San Francisco fell onto a parking lot, smashing cars; Five people died. And in a 6.3-magnitude earthquake that struck Christchurch, New Zealand, in 2011, bricks fell on the red bus number 702, killing eight people, including the driver.

The number of people who need shelter after a major earthquake can be overwhelming. The study estimated that an earthquake so massive that has a 1 in 250 chance of occurring in any given year could result in more than 200,000 people needing short-term shelter in California. In an earthquake so large it had a 1 in 1,000 chance of it occurring in any given year, more than 700,000 people would need short-term shelter.

Cars crash into a brick wall that collapsed near Fifth and Townsend Streets in San Francisco during the 1989 Loma Prieta earthquake. (CE Meyer/USGS)

The latest study also provides a more realistic picture of projected damage in places including Los Angeles and the San Francisco Bay Area, Jeswal said, where many buildings sit atop basins that amplify ground motions during an earthquake. This shaking can result in a worse outcome for tall buildings that sit atop basins than for those built directly on bedrock.

“If you have a deep basin, where sediment is overlaid on hard rock, those ground movements are amplified,” Jaiswal said.

Compared to previous models, the latest report factored in soft local soil and pond conditions, which contributed to the projected damage cost for places like Los Angeles and the Bay Area.

Other areas that have experienced an increase in earthquake risk from the previous model include the Salt Lake City area, much of the island of Hawaii, the Maui Valley region and the southern coast of Oahu.

The Seattle area has been estimated to have an annual earthquake loss of $781 million; Portland area ore $403 million. Salt Lake City area $174 million. Memphis, Tennessee, $131 million; and the New York City area, $49 million.

The fact that there is a seismic hazard in areas of the eastern United States may come as a surprise, but earthquakes like this can happen. A 5.8-magnitude earthquake near Mineral, Virginia, in 2011 caused between $200 million and $300 million in damage and required $15 million for repairs to the Washington Monument.

Other devastating earthquakes in the eastern United States recorded once off Cape Ann, Massachusetts, in 1755, were estimated to have a magnitude of 5.9, destroying the Boston waterfront; a 4.5-magnitude earthquake near Petersburg, Virginia in 1774, that knocked homes off their foundations and was felt by Thomas Jefferson; and a magnitude 7 earthquake near Charleston, South Carolina, in 1886 that killed 60 people, according to the USGS.

In the early 19th century, there were three large earthquakes in the New Madrid seismic region, around the area along the Mississippi River where Tennessee, Kentucky, Illinois, Missouri, and Arkansas meet. The largest earthquakes had a magnitude of 7.5 in December 1811, a magnitude of 7.3 in January 1812, and a magnitude of 7.5 in February 1812.

“Earthquakes are a national problem,” the USGS said in a statement.

New York City has a low probability of a devastating earthquake, but one that does occur could cause significant damage due to the city’s density and the age of its buildings, according to the city’s Emergency Management Agency. One of the big dangers for New York City is the large number of old brick buildings that have not been updated.

This story originally appeared in the Los Angeles Times.

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