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7.0 magnitude earthquake causes extensive damage to Alaskan infrastructure

A 7.0 magnitude earthquake struck north of Anchorage, Alaska’s largest city, on November 30, causing major infrastructure damage. The earthquake occurred in a seismically active region along the Alaska-Aleutian subduction zone, where the Pacific plate is forced underneath the North American plate.

The earthquake triggered a tsunami warning for southern Alaska, but the warning was later canceled. The USGS reported that as of December 2, 162 aftershocks of magnitude 3.0 (large enough to be felt) or above have occurred, including the 5.7 magnitude aftershock which occurred 7 minutes after the main shock. More aftershocks are likely to occur this week, but are unlikely to be as strong as the initial one. Outgoing Alaska Governor Bill Walker issued a disaster declaration, which President Trump later approved to provide federal funds for recovery.

Aerial assessments were used to determine road damage from the November 30 Earthquake. (Source: Flickr, Alaska National Guard)
Aerial assessments were used to determine road damage from the November 30 Earthquake. (Source: Flickr, Alaska National Guard)

As the state works to recover from the earthquake, the focus is largely on infrastructure. Several major highways and roads suffered severe damage, causing closures and delays Friday and into the weekend. The Alaska Railroad shut down all operations due to flooding and power outages to the railroad’s dispatch center and is not expected to resume service until damage is assessed. Power outages and phone outages were reported throughout the region. The Anchorage Water and Wastewater Utility reported numerous pipe breaks, while the Alaska gas utility ENSTAR Natural Gas had over 600 reported leaks. By Saturday, most power, water, and communications had been restored, but repairs to the roads – including Glenn Highway, which links Anchorage to the suburbs in the North – could take much longer to complete

One stroke of luck was that the Port of Anchorage, which receives about 90% of all goods sold in Alaska, was undamaged, allowing grocery and fuel supply chains to avoid cascading disruptions.

Despite the widespread infrastructure challenges, there were relatively few reports of collapsed buildings and structural damage and zero reported deaths. Experts credit the stricter building codes that were adopted following the 1964 magnitude 9.2 earthquake that devastated buildings in Anchorage, as well as the relative deepness of the earthquake.

Regarding the earthquake, Anchorage mayor Ethan Berkowitz said, “Anchorage is prepared for these kind of emergencies. … People pulled together, we followed the plans that were in place, we looked after one another. When people around the country and around the world look at this, they’re going to say ‘we want to do things the Anchorage Way’ because Anchorage did this right.”

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Editor’s Note: Last September, GRI Founding Director Dr. Stephen Flynn led a critical interdependencies workshop in Seattle, focused on bolstering preparedness and resilience for a megaquake, in cooperation with the Pacific NorthWest Economic Region (PNWER). During the workshop, GRI assisted in the development of three areas: long-term regional recovery, critical energy and transportation interdependencies and cascading failures, and the integration of private businesses into planning, response and recovery. Ultimately, workshop participants uncovered four key takeaways and recommended actions to address the impacts of the megaquake scenario. To learn more about this study and its findings, click here.

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Sources and Further Readings

2018 Anchorage Earthquake – USGS

Trump: Alaska got the ‘big one’ – Politico

Earthquake and Aftershocks Damage Infrastructure Throughout Alaska – Governing

Alaskan officials say infrastructure remains greatest concern after Earthquake – NBC News

The Anchorage Earthquake Was Terrifying. But the Damage Could’ve Been Much Worse. – The New York Times

Alaska earthquake aftermath: Officials urge residents to avoid roads – CBS News

‘Building codes mean something’: Alaska quake damage could have been much worse, experts say – The Chicago Tribune