The West Coast can’t escape the ‘big one’ — but the scale of its destruction is up to us

America’s Pacific coast is crisscrossed with geological fault lines, some which are historically overdue for a major earthquake. Experts tell Io Dodds that last month’s devastation in Turkey and Syria sent a clear message — but one that not everyone wants to hear

(Getty/iStock)

Somewhere underneath the rubble, Mike Leum could hear a woman's voice. It was five days since the cataclysmic earthquakes that had shattered cities across Turkey and Syria, and thousands of people were still missing in the wreckage of collapsed buildings.

Mr Leum had arrived in Turkey one day earlier on 10 February, leading a small team of volunteers from the Los Angeles County Sheriff's Department. Along with colleagues from LA's fire department and public works agency, the veteran search and rescue worker was one of nearly 9,000 foreigners from 68 countries who came to Turkey's aid.

"The devastation was immense and widespread," he tells The Independent. "Frequently we were just removing debris buckets at a time... it was back-breaking work."

Workers were ultimately able to rescue the woman in the rubble, along with her 18-year-old son. Then Mr Leum returned home to California, where scientists say the chance of a similarly powerful earthquake within the next 30 years is roughly 50-50.

"Yeah, it could easily happen here," observes Mr Leum.

America's Pacific coast is crisscrossed with geological fault lines, many bearing close similarities to those of Turkey and Syria. Some are historically overdue for a major quake, which could kill thousands or tens of thousands of people and cause tens of billions of dollars worth of damage.

That is why US scientists, engineers, and government officials are closely studying February's earthquakes for lessons about how to prepare for the next West Coast "big one".

Last week legislators in Los Angeles County, which governs much of the territory surrounding the city of LA, voted unanimously to take action against the kind of flawed concrete-framed buildings that killed so many people in Turkey.

The motion could is a first step towards requiring apartment complex owners to retrofit such buildings against collapse, just as the city of Los Angeles itself did in 2015. San Francisco officials are also considering such a law.

Meanwhile, the tragedy has jolted some homeowners in the San Francisco Bay Area to consider hardening their houses against earthquake damage, according to local contractor Howard Cook.

"Whenever there is a big earthquake, we always get more business," Mr Cook, a former earthquake assessor for the Federal Emergency Management Agency (FEMA) who now runs a construction firm called Bay Area Retrofit. "We also get business when there is a small earthquake here. When people are shaken up they think about doing something."

Yet there are major barriers to retrofitting all the West Coast's vulnerable buildings, not least the considerable expense of such works and the lobbying power of big landlords.

"We've found time and time again that it's only after large earthquakes that there's adequate political will to change anything," says Terrence Paret, a longtime earthquake engineer at Wiss, Janney, Elstner Associates, who spent weeks in Turkey studying the disastrous 1999 İzmit quake and who has helped harden historic buildings from Alcatraz to the Washington Monument.

"In California, a number of times, there's been an earthquake that caused damage and suddenly there's the will to pass new law. This is how it happens every time, invariably."

'A poster child for what’s going to happen in California'

The initial quake on 6 February came just after 4am Turkish time, with its epicentre near Gaziantep on the border with Syria. At a seismic magnitude of 7.8, it was the strongest such tremor in Turkey since 1939, and was followed by thousands of aftershocks.

Across both countries, hundreds of thousands of buildings collapsed or suffered serious damage. The death toll was massive: nearly 47,000 in Turkey and in 6,700 in Syria, as well as hundreds of thousands displaced from their homes.

And, in the wake of the tremors, there came not only rescue workers like Mr Leum but scientists, engineers, and architects from across the world, hoping to learn from the disaster.

"These have been very high interest events," says David Cocke, president of the California-based Earthquake Engineering Research Institute (EERI), which has been helping coordinate such "earthquake reconnaissance" missions around the globe since 1973.

Most earthquakes spring from fractures in the earth's crust known as faults, often forming the boundary between tectonic plates. While these plates usually move extremely slowly, they can sometimes get stuck, straining against each other until a sudden slip causes them to lurch.

Turkey sits on its own tectonic plate called the Anatolian Plate, sandwiched between the Eurasian Plate and the Arabian Plate pushing up from the south. Similarly, the North American Plate is rubbing up against the vast Pacific Plate as they drift past each other in opposite directions, part of the infamous 25,000-mile-long “ring of fire” that surrounds the Pacific Ocean. Off the coast of Oregon and Washington, a smaller plate called the Juan de Fuca is slowly being dragged underneath the North American, creating a giant fault known as the Cascadia Subduction Zone.

The Cascadia fault is less active than those in California, but has a higher potential for destruction. A massive magnitude 8.7 to 9.2 quake in the year 1700 is thought to have caused a tidal wave in Japan nearly 5,000 miles away, as well as possibly inspiring native American legends. Scientists estimate a 37 per cent chance of a magnitude 7.1 or greater earthquake striking within the next 50 years, with a 14 per cent chance of a magnitude 9.

California’s earthquakes cannot match that power, but are far more frequent. State officials predict a 48 per cent chance of a magnitude 7.5 or greater earthquake somewhere in the state within the next 30 years.

According to some scientists, California’s complex fault systems bear a close resemblance to those in Turkey. “This earthquake is a poster child for what’s going to happen in Southern California," Colorado geology professor Karl Mueller told California broadcaster KTLA. University of Washington expert Harold Tobin also drew comparisons between Turkey's North Anatolian Fault and the Seattle Fault.

Researchers are particularly alarmed by the severe "back to back" aftershock that worsened February's disaster. At a magnitude of 7.5, it was ten times stronger than typically expected, partly because it actually originated from a separate fault. That suggests the same thing could happen after a quake on California's famous San Andreas Fault, posing extra challenges for disaster response.

"Most commonly you’ll see aftershocks on the fault that ruptured in the main earthquake or immediately adjacent to it," seisomologist William Barnhart told The New York Times. "But when you get into these regions where you have a spatially complex fault network, you can also get large aftershocks on different faults some distance away.... if you had a large San Andreas Fault earthquake, could you also have a quick follow-up on the San Jacinto fault, or the Garlock fault?"

Fellow seismologist Ross Stein likewise said: "There is no question that we’re going to learn an enormous amount."

The West Coast has thousands of potentially unsafe buildings

Another lesson for American cities lies in the rubble itself. According to David Cocke, the damage in Turkey was far worse than many engineers expected given Turkey's "pretty modern" building regulations, which should have prevented such widespread devastation.

Those regulations are based on similar laws passed by California and other western US states after the 1971 San Fernando earthquake, in which officials were shocked by the collapse of supposedly earthquake-resistant buildings including a psychiatric ward and a freeway overpass.

Then and now, one of the key culprits was a type of architecture that is widely used across the world. The San Fernando buildings were supported by concrete columns, reinforced with metal beams to make them more "ductile", or flexible. This reinforcement included metal hoops wrapped horizontally around the inside of the columns, but their design turned out to have a fatal weakness.

Imagine carrying a basket of rocks and swinging it from side to side. If the basket's woven strands were too far apart, some of the rocks would fly out. That, says Mr Paret's colleague Robert Kraus, is roughly what can happen when the vicious lateral motions of an earthquake cause solid concrete to fracture into smaller chunks. Without a dense enough "basket" of reinforcing hoops, these chunks will break off the column until it can no longer support the weight of the building on top of it.

This type of "non-ductile concrete", or NDC, has been banned in new buildings by most US states since the late 1970s. But Turkey did not follow suit until the late Nineties, and Mr Paret says its rules have been poorly policed.

"In California there's a pretty well-enforced system of plan check and building inspection," says Mr Paret. "These are things that have been absent from Turkey for a long, long time, and you're reading about them now – builders getting away with a lot of stuff that they should never have gotten away with."

Mr Paret and Mr Kraus stress that even a very severe earthquake could not cause the same devastation in the US, precisely because its building regulators have learned the lessons of 1971. "Turkey outstrips us a hundred to one, a thousand to one, in terms of the number of these buildings," says Mr Paret. "Almost everything is an NDC building... it's entire cities constructed with the same technique".

He adds that Turkish apartment buildings often compound this with a tall, largely open-plan ground floor for shops, which may prove unable to hold up the other floors in a serious earthquake.

Mr Leum agrees, saying that California would “fare much better than almost anywhere else in the world” thanks to its decades of improving building standards.

Six days after the first quake in Antakya, Turkey, February 2023 (Petros Giannakouris/AP)

Nevertheless, the western US still has plenty of NDC offices and apartment complexes that predate the late Seventies, which could become deathtraps in a serious quake. "There's thousands and thousands of buildings out there that have not been retrofitted," says David Cocke. "One of the big lessons [of Turkey] is that we need to go back and evaluate and retrofit those buildings, or we're gonna have problems."

Estimates vary as to how many remain. In California, it could be anything from 7,000 to 40,000, with nearly 4,000 in San Francisco alone. Numbers for Washington and Oregon are murkier still. According to the USGS, a magnitude 7.8 earthquake in southern California could collapse around 50 NDC buildings, with as many as 7,500 people caught inside.

Meanwhile, the city of Portland estimates that it has about 1,800 buildings made of similarly vulnerable unreinforced masonry (URM). Seattle estimates 1,145, and the The Los Angeles Times found as many as 640 across the greater LA area.

There is also a risk to individual homes, which are subject to looser regulations. "People don't get killed in houses unless they're on a steep hill," says Howard Cook. "But there will be hundreds of thousands of people without a home. Where are they going to go?"

Earthquake safety advocates face an uphill battle

This situation is what LA County's board of supervisors is now trying to address. Their new motion asks officials to prepare new rules requiring mandatory retrofits to all NDC buildings in unincorporated areas – that is, areas not subject to their own city governments – as well as buildings owned by the county itself.

“While there are only a handful of non-ductile concrete buildings in unincorporated areas or owned by the county, the county must insist on renewed urgency to retrofit and repair vulnerable structures to prevent as much loss of life as possible," stated the motion, according to The Los Angeles Times.

It also orders an inventory to be taken of all "soft-storey" residential buildings in the county, meaning buildings whose upper levels are held up by slim supports so that cars can park on the ground floor.

Full retrofit mandates remain rare in the US. California leads the way for NDC buildings, starting with the city of Los Angeles in 2015, followed by Santa Monica and West Hollywood. San Francisco is slowly working towards a similar order, having successfully forced retrofits of most URM buildings after the 1989 Prieto quake.

Soft-storey retrofit mandates also exist in the Bay Area cities of San Francisco, Berkeley, Oakland, and Fremont, as well as the greater LA cities of Culver City, Beverly Hills, and Pasadena.

Los Angeles firefighters prepare to deploy to Turkey on 6 February 2023 (Allison Dinner/EPA)

California passed a URM retrofit mandate in 1986, but left it up to local jurisdictions to decide how they should comply. Mr Paret says many places decided it was enough to just put up signs warning people that a given building was unsafe, like the ubiquitous and largely ignored cancer warnings plastered on everything from couches to coffee shop cash registers in the Golden State.

For individual homes, Mr Cook says there is practically no regulation, meaning owners may pay thousands of dollars for modifications that won't actually protect them from quakes. "They're completely worthless," he says of Bay Area governments. "Once the earthquake hits, and a bunch of people die and are injured, all of a sudden things will change."

Moreover, LA's order may already be failing in its goals. According to a 2021 white paper by the architecture firm Omgivning, after the first six years of the mandate only 31 per cent of affected buildings had completed the three-year goal of submitting a works checklist to city officials, while just under 4 per cent had actually completed construction. That was despite the mandate's very long deadline for all buildings to be retrofitted – 25 years from the date that building owners get notice.

"I absolutely believe we're not going to hit that target, and furthermore we're going to fall well short of it," says Omgivning project director Roberto Vazquez. "That doesn't go to say that we can't get there... [but] if we put 100 per cent on the burden on the building owner, it almost never works out."

To start with, retrofits can be tremendously expensive. Mr Kraus estimates around $150 to $200 per square foot in downtown LA, meaning the biggest apartment buildings run into the low tens of millions. Mr Vazquez says Omgivning regularly gets calls from building owners who have received a notice from the city – but "unfortunately, once they learn how much it's going to cost, they take our assessment and probably tuck it away in a folder in a drawer somewhere."

It can also be hard to tell exactly which buildings need retrofitting. A well-reinforced concrete column and an NDC column can look identical from the outside, while blueprints for old buildings are often missing. Finding the truth requires painstaking detective work or physical examinations with metal detectors, ground-penetrating radar, and even chipping hammers to manually expose the metal within.

Finally, retrofits are logistically complex and can be very intrusive. Mr Vazquez says they typically take 6-12 months, with buildings often losing plumbing, electricity, and water for some of that time. In residential buildings, it can cost just as much to temporarily rehouse tenants as it does to perform the work itself.

That is to say nothing of what happens when a building has many different owners, such as a condo complex, or changes hands several times over the years. "These are very difficult problems – one might say insurmountable," Mr Paret warns.

'Get to know your neighbours – your life may depend on them'

Unsurprisingly, local and state governments have often baulked at either forcing such costs onto landlords or spending taxpayer money on them. In 2015, then California governor Jerry Brown vetoed a bill that would have allowed building owners to claim back 30 per cent of their retrofit spending as a tax credit.

"The problem I have is the way they’ve gone about it," said Mr Brown at the time. "They’ve identified the problem. They’ve established a set of rules and guidelines... but they’ve done so without providing an easy and reasonable means of funding all this extra work."

Yet Mr Cocke says big landlords have tended to resist being asked to pay for the work themselves. "I don't want to say real estate developers are evil or anything like that; I work for a lot of them," he says. "But there's always gonna be somebody that says 'oh, you're going to mess up our economic model by doing that'."

Of course, he adds, "the risk that you're living with is that there's gonna be an earthquake and your building is going to be significantly damaged, and your operations are going to be shut down for months and months and months."

Indeed, LA County's effort was challenged by the Apartment Association of Greater Los Angeles, which argued that its members were "barely surviving" after pandemic-era rent freezes and warned that creating an inventory of soft-storey apartment buildings would cause insurance premiums to spike.

"While seismic retrofitting serves a vital need, it is important to recognise that these projects are extremely costly," said lobbyist Max Sherman, according to The Los Angeles Times. "We ask the county to not start this process with housing providers still reeling from financial hardships."

The California Apartment Association likewise asked LA County to seek feedback from owners about the right timeline for a retrofit order. An interview request from The Independent met with no response.

Still, Mr Vazquez believes that retrofit mandates can work if building owners have proper incentives. Even without spending state funds, officials could relax planning rules and other forms of red tape in exchange for retrofitting, or bid for some of the $1.3 trillion in federal funding released by Joe Biden's landmark 2021 infrastructure law.

"These buildings [collapsing] can damage the pedestrian on the street; they can damage other safe buildings that are adjacent to them," he says. "It should be looked at as public infrastructure and a public benefit."

Mr Paret is sanguine about these headwinds, saying that engineers like himself sometimes need a “reality check” about local governments’ long list of competing priorities. Nevertheless, he, Mr Kraus, and Mr Vazquez all said the calamity in Turkey could help shift public opinion and catalyse government action.

"I expect and can well imagine that there will already have been some very heated homeowners' association meetings, with some members being frightened and demanding action in ways that maybe weren't happening before," says Mr Paret. "Whether the heated meetings translate to actual results – that I'm not so confident in."

Until then, Mr Leum has stark advice for West Coast residents that does not require any government intervention. "The lesson to be learned is that there won't be enough rescue personnel," he says. "If a similar situation happens in the US, it's going to be primarily neighbour helping neighbour...

"So get to know their neighbours, because there's a pretty good chance that your life might depend on them, and theirs might depend on you."