Engineering Lessons Learned from the Chile Earthquake

The New York Times
March 28, 2010
Op-Ed Contributor


Shake, Rattle, Seattle
By PETER YANEV

AS an engineer who advises companies on how to make their buildings survive earthquakes, I have visited the aftermath of nearly every key quake since 1970, observing how new and old buildings have performed when the ground shook beneath them. I try to learn from each new disaster how to change our design techniques, construction practices and building codes to reduce future losses of life and damage. From my perspective, the shock that hit Chile in February was the most important earthquake of the last 100 years.

It was the first mega-quake, its magnitude near 9, to strike a developed country with rigorous building codes. Modern cities full of state-of-the-art buildings were tested by intense ground-shaking that lasted about 120 seconds — compared to about 40 seconds for the 1906 and 20 seconds for the 1989 San Francisco earthquakes, which had magnitudes of 7.9 and 6.9, respectively. Despite Chile’s exacting construction codes, which often exceed those of California and Japan, the performance of numerous high-rise buildings was worryingly poor.

We engineers and seismologists need to gather and study as much data as we can from Chile’s quake. But one thing is already clear: based on the kind of damage that buildings suffered in Chile, tall structures in the earthquake zones of the United States appear to be at much higher risk than we thought. This lesson should be of obvious concern to San Francisco and Los Angeles. But it is actually the Pacific Northwest that is most vulnerable to a mega-quake like Chile’s.

Just off Northern California, Oregon, Washington and British Columbia sits the 600-mile-long Cascadia fault. Like the Nazca tectonic plate that caused the quake and tsunami in Chile, Cascadia can produce temblors with magnitudes of 9 or greater, more powerful than anything we’ve experienced or expect from California’s famous San Andreas fault.

Cascadia’s last mega-quake, in January 1700, was approximately as large as Chile’s; it caused a tsunami that pummeled Japan. Many seismologists believe the Pacific Northwest is overdue for another mega-quake. Yet in cities like Seattle, Vancouver and Portland, Ore., hardly any building is designed to withstand such a huge jolt.

That is precisely why it is so important to understand what happened in Chile, which has a history of huge earthquakes. The previous one, in 1960, had a magnitude of 9.5 and caused widespread destruction. Chileans responded with better construction codes, better structural and earthquake engineering; buildings were made with massive reinforced concrete frames and backed by numerous reinforced concrete walls, called shear walls. However, over the last decade, more fanciful architecture and financial pressure to reduce costs have resulted in new buildings with fewer and more slender shear walls.

In Concepción, an industrial city closer to the epicenter, those terrifying two minutes left 20 percent of buildings 15 or more stories tall damaged beyond repair. Most of the failed buildings were new; several were still for sale. These buildings had fewer shear walls than older Chilean structures, but they were still stiffer and stronger than many buildings in California.

Another major lesson comes out of Santiago, an area of relatively weak shaking. There, a large, high-end office development called Ciudad Empresarial was still under construction when the quake hit. Again, the buildings of Ciudad Empresarial were a lot like trendy offices in Silicon Valley, cheaper and more flexible than the structural designs usually found in Chile.

The buildings themselves were largely undamaged, or suffered only moderate damage. But many of the interior architectural features — suspended ceilings, expensive finishes, interior partitions, heating and ventilating equipment, air-conditioning ducts and some of the water piping — were utterly destroyed. If the earthquake had occurred during the workday, the damage would have caused many casualties.

Construction codes are based on the probability of earthquakes striking a region. That means Seattle’s buildings, for example, are designed for roughly half of the earthquake loads of buildings in San Francisco or Los Angeles, because earthquakes occur roughly half as often in Seattle as in California’s cities. But the result is that Pacific Northwest cities are full of buildings with slender structural frames and fewer and smaller shear walls. In a mega-quake, many of the region’s iconic tall buildings would probably collapse. The loss of life and property from such a disaster would be far worse than the damage and death suffered in Chile.

It is only a matter of time before a quake like the one in 1700 happens again in the Pacific Northwest — perhaps tomorrow, or not for 20, 50, 100 years. We do not know that precisely. But we do know that the earthquake will happen. Are we ready? No, we are not. Not in California, and definitely not in the Pacific Northwest.

Peter Yanev, the author of “Peace of Mind in Earthquake Country,” runs a structural engineering and earthquake consulting firm.

Copyright 2010 The New York Times Company

The Great ShakeOut Report

As a member of the LAFD Auxiliary Communications Service, I was privileged to participate with the ACS in this drill. Our task was to set up multiple HF radio communication stations and communicate with each other using NVIS propagation. In plain English, we set up and exercised comm systems that allowed us to have communications over a wide area using Amateur Radio 'shortwave' frequencies.

I am very pleased to report that all of our stations, including portable stations at several regional hospitals, were able to contact each other, and we were able to maintain communications to the City of Los Angeles Emergency Operations Center, and the Office of Emergency Services in the Governor's Office in Sacramento. Had this been a real emergency, we would have been able to provide emergency communications as necessary.

The Drill did expose some shortcomings in our training -- especially in formal message handling, and we'll continue to train and improve.

The following is a report of the Great ShakeOut drill. Interesting information inside...

Moderator

http://www.latimes.com/news/local/la-me-quake27-2008dec27,0,2002741.story

From the Los Angeles Times

Major Southern California quake drill reveals significant gaps in preparations

The Nov. 13 'shakeout' showed officials that in the event of a 7.8-magnitude temblor they will need more emergency workers, better sources of water and come up with new ways of restoring electricity.

By Jia-Rui Chong

December 27, 2008

The largest earthquake drill in U.S. history, held last month in Southern California, found some serious gaps in local earthquake planning, prompting utility companies, emergency managers and others to rethink their planning for a major temblor.

The Great Southern California Shakeout was the first time so many agencies and earthquake officials teamed up to examine what would happen if a huge quake struck the region, in this case a 7.8 magnitude temblor. Many Shakeout participants said they have gone through earthquake drills before, but never with a scenario so detailed.

Based on the results of the Nov. 13 experiment, in which each agency estimated damage and emergency services requirements based on detailed quake scenarios developed by supercomputers, officials said they will need more emergency workers, better sources of water and come up with new ways of restoring electricity.

Fire protection

For local fire officials, one of the most worrisome estimates from the drill was the 1,600 fires expected to ignite with lamps overturning, electrical wires shorting and natural gas lines bursting open. Many fires would grow out of control as firefighters struggle to get fire engines across damaged roads and water stopped coming out of their hoses, experts found.

An estimated 200 million square feet of property would be damaged in the blazes. The fires would cause more than 900 deaths -- about half of the total for the earthquake.

"To hear it quantified like that, it more than got my attention," said Los Angeles County Fire Chief Michael Freeman. "This was really the worst-case scenario for us. Today, if this were to happen, we would need outside assistance."

Unfortunately, Freeman said, they probably would not get help for quite some time because neighboring fire agencies would be fighting fires in their own districts and departments from Northern California would have to make their way around damaged highways. Because they can't afford to multiply their staffs, several fire agencies are looking into training more members of the community to be first responders, learning such skills as basic first aid and turning off gas lines.

Freeman said the county is also looking into ways to better draw water from other sources during a disaster, such as pools or storm drains that are collecting runoff from broken pipes.

Water supplies

But the drill also raised troubling questions about how much water would be available after a major quake. Of all utilities, water would take the longest time to restore, experts found. Some communities might have to wait six months for taps to flow again.

The Shakeout helped officials at East Valley Water District in San Bernardino County estimate that they would see about 1,000 leaks in their 450 miles of pipe because about 40% of their pipes are made from a material that is particularly brittle in earthquakes, said Gary Sturdivan, the district's safety and regulatory manager. All 78,000 of its customers would lose water for some period because all of the agency's reservoirs are on one side of the fault and all of its wells and distribution systems are on the other.

As a result, the district plans to stock more replacement pipe parts in repair sheds near those areas and store more bottled water for their employees, employees' families that might stay at their facilities and their customers who need water, Sturdivan said.

The water agencies are also retooling their mutual-aid agreements so they can figure out how to prioritize different agencies' needs and distribute replacement parts or water from other states fairly, he said.

"I think our agency, like a lot of water agencies, was pretty prepared, but it was glaring that we have a long way to go," Sturdivan said. "It was a little overwhelming."

Electrical supplies

The 7.8 temblor modeled by the test would leave large swaths of Los Angeles, San Bernardino and Riverside counties without power, according to estimates by a working group that included utility companies representatives. Breaks in natural gas pipelines could add delays because many plants use gas to generate electricity. It probably would take about 10 days to restore power to 90% of customers, the estimates found.

But Jim Kelly, senior vice president of transmission and distribution for Southern California Edison, said even that is an optimistic forecast.

"The problem is harder than people initially think," he said. Although Edison already uses equipment designed to be safer in earthquakes, such as transformers with low centers of gravity, Kelly worried about other utilities and parts vendors that would probably be having problems at the same time.

"If we lose bridges or roadways, how are we going to get people or materials to the job site," Kelly asked. "We don't know if rail transit will be available if we don't have roadways."

When Kelly added these potential problems together, he estimated it would take two to four weeks to restore power to the vast majority of Edison's 12 million customers.

"The scenario's value to us was in identifying that we have to look broader than just our stuff," he said.

Lucile Jones, the U.S. Geological Survey seismologist who served as the chief scientist for the Shakeout, said she hopes the drill gave agencies concrete data that will help them better prepare.

"People don't need to be convinced an earthquake can happen," she said. "They need concrete statements so they know what to do about it."

The effort to develop the scenario cost about $500,000, engaged some 300 experts and took two years to complete.

Geophysicists wanted to plot a plausible event, so they started the earthquake at a part of the San Andreas that has not moved for more than 300 years. They decided the energy stored in that part of the fault could cause a 200-mile rupture moving northwest from Bombay Beach, at the Salton Sea. Quakes of this size are possible, Jones explained, because they rocked San Francisco in 1906 and Fort Tejon in 1857.

Seismologists used the supercomputers to calculate the shaking, generating data for 25,000 points of a grid laid out over Southern California.

Geologists, engineers, utility managers and other experts used the data to estimate the damage, which included more than 10,000 landslides, more than 50 sewage spills and more than 100,000 addresses losing phone and Internet service for two or more days. Motorists would have to wait one to two weeks to use arterial roads in cities such as Los Angeles and seven months to use damaged highways.

Public health experts estimated some 1,800 people would die and 50,000 would be seriously injured. The economic costs of the disaster, including the business interruption, would total about $213 billion.

The scientists purposefully avoided a worst-case scenario but wanted to analyze an earthquake far more damaging than the 1994 Northridge earthquake, which had a magnitude of 6.7. "We wanted people to understand how bad it could be," Jones said. "Some people think, 'I've been through Northridge,' but getting through Northridge is not enough."

jia-rui.chong@latimes.com

ACS-CERT Combined Radio Communications Plan

For several years now we have been encouraging our Community Emergency Response Team (CERT) members to obtain their FCC Technician Licenses. We showed them the need to use Amateur Radio Frequencies to communicate at times when normal communications are likely to be impaired.

Well, it's worked...

I'm happy to report that a significant number of CERT members in Los Angeles now have their Tech Licenses -- enough that I have written a new combined Radio Communications Plan for all the volunteers for the Los Angeles Fire Department. The Plan follows LAFD communication protocols and is currently being approved by the LAFD Staff.

The new plan includes both the existing frequencies used by the LAFD Auxiliary Communications Service, and additional frequencies for the CERT radio operators. It also includes instructions for using FRS radios at each incident so all responding CERT members, FCC licensed or not, will be able to communicate back to the CERT Incident Radio Operator.

The plan includes sufficient frequencies and alternate frequencies that the LAFD volunteers should be able to maintain adequate communications even if there are multiple incidents within a Battalion, or multiple Battalions involved in a larger emergency.

We realize this plan is just a beginning, but it will be a good start.

When all else fails, Amateur Radio Works.

Your Moderator

Jonathan Zimmerman K6JGZ
LAFD ACS-CERT Liaison
Battalion 14 Communications Unit Leader