As if we didn't have enough to worry about when it comes to our crumbling infrastructure and how it holds up to everyday traffic, some people are asking the question: What happens if there's a major earthquake?

I was working at another trucking magazine 22 years ago when the 1994 Northridge earthquake hit the Los Angeles area. The 6.7-magnitude quake gained worldwide attention because of damage to the vast freeway network.

On top of the deaths and injuries that can occur on highways and bridges during the earthquake itself, roads are severely damaged and bridges that are too dangerous to cross or have collapsed completely can wreak havoc on emergency response and the ability of people to get to shelters or to food and water handouts.

The video above is a 2009 simulation of how an earthquake could affect the Alskan Way Viaduct, part of Washington State Route 99, in downtown Seattle.

Washington State recently held the largest earthquake preparedness drill in its history, and the state Department of Transportation had a major role to play.

As reported by, "Pretending there was an earthquake the likes of which we’ve never experienced in the Northwest, WSDOT faced the responsibility of tackling a crumbling infrastructure across the state. While pieces of Interstate 5 were completely destroyed, cutting off the state’s main north-south route, the agency also dealt with 72 collapsed bridges and 47 more that were unstable or otherwise closed. More than 100 roads closed and another 56 had restrictions due to heavy damage."

As the article noted, exactly how many roadways and bridges will be affected is impossible to predict, but the number of bridges in “poor” condition in the state was 141 in 2014, according to state reports.

Damaged portion of the Golden State Freeway (I-5) at Gavin Canyon after California's Northridge earthquake in 1994. By Robert A. Eplett from the FEMA Photo Library.

Damaged portion of the Golden State Freeway (I-5) at Gavin Canyon after California's Northridge earthquake in 1994. By Robert A. Eplett from the FEMA Photo Library.

As part of its bridge preservation program, WSDOT uses seismic retrofit of bridges to mitigate the potential risks. The purpose of the Seismic Retrofit program is to minimize and avoid catastrophic bridge failures by strengthening bridges and structures to resist future earthquakes. More than 900 bridges are part of the Bridge Seismic Retrofit Program. These bridges are located on state routes basically west of a line drawn through the center of Washington State (west of Wenatchee and Yakima). Retrofit priorities are based on seismic risk of a site, structural detail deficiencies, and route importance. 

However, it's unclear how much this program is addressing an issue reported on earlier this year by KUOW: Some of the state's busiest bridges are held up by hollow concrete columns that could be at risk of "instantaneous implosion" in a major earthquake.

"If a severe earthquake hit, there's a high risk that the inside could break loose, and the column could actually implode," DeWayne Wilson, a bridge engineer with Washington State Department of Transportation, told the radio station.

About the author
Deborah Lockridge

Deborah Lockridge

Editor and Associate Publisher

Reporting on trucking since 1990, Deborah is known for her award-winning magazine editorials and in-depth features on diverse issues, from the driver shortage to maintenance to rapidly changing technology.

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