Twenty years after the Northridge Earthquake, is the Westside any better prepared for The Big One?

By Gary Walker

Damage to the Sea Castle Apartments in Santa Monica in 1994

Damage to the Sea Castle Apartments in Santa Monica in 1994

 

 

 

 

 

 

 

 

 

 

 

 

 

At 4:31 a.m. on Jan. 17, 1994, Los Angeles awoke in darkness to the shaking of a 6.7-magnitude temblor that toppled buildings, collapsed freeway bridges and knocked out water and power to many homes and businesses.

The Northridge Earthquake — which hit the San Fernando Valley and Santa Monica the hardest, according to U.S. Geological Survey maps — left dozens dead and caused property damage in the tens of billions of dollars, making it one of the costliest natural disasters in American history.

The quake and its aftermath prompted numerous changes to local building codes, but even a full 20 years afterward, experts say many potential hazards remain if L.A. were hit by The Big One today.

“Overall, the news is not great, I’m afraid,” said UCLA civil engineering professor Jonathan P. Stewart, who was part of a research team that studied the collapse of the Santa Monica (10) Freeway at La Cienega Boulevard during the Northridge quake.

“I worry that if a major earthquake were to occur, particularly if near downtown or certain parts of the Westside, we could see a number of collapsed buildings and significant loss of life,” Stewart said. “We are in much better shape with bridges. Certain parts of the water distribution infrastructure have also been improved. Many weaknesses remain, however, mostly with older buildings.”

Of particular concern to Stewart is the San Andreas Fault. Where the Northridge Earthquake rattled along a smaller, previously undiscovered fault, a San Andreas temblor could be much more powerful and cause damage over a wider area, resulting in “multiple building collapses and widespread disruption in basic [utility] services,” he said.

Hard truths about soft-story structures

Stewart and other experts have focused safety concerns on so-called soft-story structures — namely wood-framed apartment buildings with parts that hang over open parking areas.

A 2005 study by the Association of Bay Area Governments found that soft-story structures accounted for approximately two-thirds of the 46,000 buildings rendered uninhabitable by the Northridge Earthquake. The upper story of one such building, the Northridge Meadows apartments, buckled and crashed to the ground during the 1994 quake, killing 16 people as it flattened cars parked below.

The building came down “because the first story apparently had no shear panels to carry earthquake loads. The first floor toppled and the first story pancaked as a result,” said Michael Manoogian, a professor of civil engineering at Loyola Marymount University.

Last year, San Francisco officials passed an ordinance that mandates the seismic retrofit of soft-story structures.

On Tuesday, Los Angeles Mayor Eric Garcetti announced plans for an ambitious earthquake safety initiative that will begin by identifying potentially dangerous soft-story buildings.

In an unprecedented collaboration between the city and a federal agency, Caltech-based U.S. Geological Survey seismologist Lucy Jones is expected to lead the effort.

Jones said she “completely agreed” with Stewart’s sober assessment of the city’s vulnerability to a quake and believes retrofitting soft-story buildings is a good first step to bracing the region for a major earthquake, as they are among the most vulnerable structures.

“Getting rid of softer stories would save a lot of lives,” Jones said.

Stewart also called for a public program to retrofit soft-story and older concrete buildings.

Stewart, Jones and others including former California Gov. Pete Wilson will lead the Northridge 20 Symposium, an in-depth exploration of infrastructure improvements and liabilities happening Thursday and Friday at the UCLA Henry Samueli School of Engineering and Applied Science.

Westside soils could amplify quakes

The potential collapse of soft-story structures is of particular concern to Westside neighborhoods.

Softer soils, such as those on the Westside and near the Ballona Wetlands in particular, tend to vibrate more during an earthquake, Manoogian said.

Stewart blamed soft soils, which contributed to the significant damage sustained by Santa Monica despite its distance from the Reseda epicenter of the Northridge Earthquake, for the collapse of the 10 freeway in West. L.A.

“Soil conditions affect the nature of ground shaking from earthquakes, particularly soft conditions in a local area,” Stewart said. “We suspect that this local amplification of the ground shaking contributed to bridge collapses.”

Manoogian said the most significant change to building codes since the Northridge Earthquake is the inclusion of soil parameters that take into account the type of soil underneath a structure and the potential drift of a building during a quake.

During the 1994 quake, many buildings in Santa Monica were condemned or declared temporarily uninhabitable, and other Westside neighborhood are vulnerable to similar impacts during a major localized quake.

“When we look at the Los Angeles’ Westside generally, there are several places where there can be this type of local amplification, but not always for the same reasons,” Stewart said.

“Santa Monica has a different problem in the area immediately south of the Santa Monica fault [which runs roughly east-to-west above Santa Monica Boulevard east to Beverly Hills]. The issue there is deep sediments that have a lens-like shape that concentrates ground shaking. We think that focusing [effect] had a substantial impact on the severe damage observed in Santa Monica,” Stewart said.

A recent Los Angeles Times investigation revealed that tall buildings had been built in Los Angeles neighborhoods along the Santa Monica fault due to unmarked fault zones in outdated public maps.

To the south, softer soils pose potential dangers.

“Along much of Ballona Creek, including Marina del Rey, the soils are often fairly soft, so I would expect ground motion amplification there for the same reasons as at La Cienega,” Stewart said.

Stewart’s study of the 10 Freeway collapse there suggested that a soft soil bed amplified localized shaking enough to cause damage. Because similar soils exist along the cost south of Santa Monica, “if we had an earthquake at closer distance, like on the Santa Monica fault or Newport-Inglewood fault, then much of the Westside region would experience very strong shaking having serious damage potential,” he said.

As Los Angeles officials give increased attention to quake safety, Santa Monica officials plan to follow suit.

“I’ve lived in Southern California over 40 years, and Jan. 17, 1994, was the only time I’ve feared for my life in an earthquake,” Santa Monica City Councilman Kevin McKeown said.

In light of LA Times reports on deficient fault maps, the city has reviewed recent construction records. Officials, however, contend that no new structures in the city have been erected atop known faults.

“The Times report, and the anniversary of the Northridge quake, have reminded us that much may still need to be done,” McKeown said.  “At our council meeting on Feb. 11 we will consider, and I hope adopt, the toughest, most stringent earthquake safety plan in all of California.”

As of press time, city officials had not disclosed aspects of the plan in development.

Agencies boost preparation efforts

Los Angeles city and county officials say public agencies are much better prepared to respond to a major earthquake than in 1994.

The Los Angeles County Emergency Operations Center, activated after the Northridge quake, serves as a gathering point for response and recovery efforts during natural disasters, said Ken Kondo, head of the county’s Office of Emergency Management. The department is responsible for school districts and the 137 unincorporated neighborhoods within Los Angeles County, including Marina del Rey.

In the unlikely event of sea-level rise during a massive quake, Kondo said residents of Marina del Rey and areas directly on the coast should move away from the shoreline and head inland if instructed to do so after a major earthquake strikes, just to be on the safe side.

“In 20 years, we have made a lot of progress,” Kondo said. “We have created an emergency survival program and an emergency survival guide.”

Los Angeles World Airports, the entity that operates Los Angeles International Airport, partnered with county and city officials last year to update its earthquake response plans, said LAWA Emergency Management Director John Kinney.

“We are designing new structures to higher seismic standards than required by the code [including] the New Tom Bradley International Terminal, the Central Utility Plan, the LAWA Telecommunications Building, a retrofit to the Upper/Departures Level roadway, the LAX Theme Building renovation and earthquake retrofit, etc., as well as including seismic upgrades in the terminal renovations,” LAWA Deputy Executive Director for Facilities Management Michael Feldman wrote in an email.

LAWA is currently in the process of creating earthquake response teams for building assessments after an earthquake. The teams “will be able to tag a building ‘good to operate within’ or red tag it if it is uninhabitable,” Kinney said.

Working with the Red Cross, the airport is currently training its employees for disaster response and is keeping enough supplies on hand to sustain a 500-strong workforce during a three-day response-and-recovery effort, Kinney said.

The Los Angeles Dept. of Water and Power has multiple emergency response plans within each of its divisions, DWP Director of Water Engineering and Technical Services Susan Rowghani said.

“In our division, one of the things that we will be doing is that we will have people going out to inspect our dams, especially in the case of a seismic event. We would be looking at our pump stations and for leaks in our infrastructure,” Rowghani said. “We have certain people assigned to certain roles in terms of how we respond, and we all need to coordinate because if we have something like a seismic event, it’s not only water that’s going to be affected, it’s also gas, and police and fire are going to be out there as well.”

Los Angeles has also been testing an earthquake alert system that would activate immediately following a quake, said Anna Burton, the city’s interim general manager of emergency management.

“We continue to learn about the realties of the ramifications of an earthquake,” Burton said.

The Federal Emergency Management Agency was essential to the Los Angeles region’s recovery from the Northridge quake, said Rep. Henry Waxman (D- Beverly Hills), who represented Santa Monica at the time.

“I was in Los Angeles at the time of the earthquake and it was the strongest one that I’ve ever been in,” Waxman said. “I toured the damaged areas, including the Santa Monica Freeway and Saint John’s Health Center.”

FEMA responds to a disaster after a state makes a formal request, said Mary Simms, an external affairs officer for the agency.

Waxman FEMA’s work in helping rebuild the 10 Freeway as “an excellent example of how [the government] should respond in an emergency,” Waxman said.

But if Northridge was a high point for FEMA, Hurricane Katrina was perhaps its lowest.

Simms said the heavily criticized response to the 2005 Louisiana flooding ushered in new protocols for FEMA’s capabilities in a natural disaster, including how the agency develops capabilities to react to national emergencies of all types.

“It gave FEMA the opportunity to push resources before doing an evaluation of a disaster area,” Simms said.

Given the partisan wrangling that took place in the aftermath of Hurricane Sandy in 2012 regarding providing additional funding for the victims of the hurricane, Waxman said he is unsure how Congress — especially his colleagues on the other side of the aisle — would respond to future calls for increased levels of federal support.

Prepare to be self-reliant

John Gregory, legislative director for Los Angeles City Councilman Mike Bonin, said that while public officials have made plans for a major seismic event, residents should be prepared to sustain themselves for several days in the event first responders are otherwise occupied.

“Since the 1994 earthquake, every city department has its own emergency response plan.  But the city has operated under the premise that in the event of a large earthquake, resources are going to be overtaxed and people are going to have to be dependent on themselves for a while, perhaps up to 72 hours,” Gregory said.

Kondo said residents should prepare emergency supplies and craft plans for self-reliance during an earthquake.

“The more that we are prepared, the more that we will be able to help our friends, neighbors and families,” he said.

Burton recommended planning earthquake drills and updating emergency contact information.

The American Red Cross recommends that earthquake survival kits should contain at least one gallon of water per person for three days, food, a flashlight, radio, medicine, a multipurpose tool, personal hygiene items, personal documents, extra cash, a blanket and area maps.

On its website, FEMA recommends several earthquake precautions. These include fastening shelves securely to walls, placing heavy objects on lower shelves, storing breakable items in low cabinets with latches, bracing overhead light fixtures, securing large appliances and surveying rooms for secure spots under sturdy tables or along interior walls.

Gary(at)argonautnews.com

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