Some 1,800 aftershocks have been measured since Friday’s 7.0 earthquake in Alaska

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Some 1,800 aftershocks have been measured since Friday’s 7.0 earthquake in Alaska
https://www.adn.com/alaska-news/2018/12/03/nearly-1400-aftershocks-have-been-measured-since-fridays-70-earthquake-in-alaska/



Small aftershocks continued Monday from Friday’s 7.0 earthquake, with more than 1,800 measured by early evening. A total of 153 measured greater than 3.0, 18 were at 4.0 or greater and five were greater than 5.0, according to the Alaska Earthquake Center....

[thackney]

An army of engineers and contractors is working to check Anchorage homes and fix quake damage
https://www.adn.com/alaska-news/2018/12/04/an-army-of-engineers-and-contractors-is-working-to-check-anchorage-homes-and-fix-damage-left-by-70-earthquake/

The 7.0 earthquake that hit Southcentral Alaska on Friday morning sank Michael and Nikki Rose’s Sand Lake home by several inches and sliced open their driveway.

A few days later, on Monday morning, two engineers stopped by and toured the house and noted structural damage. Afterward, they handed the Roses a yellow tag. The tag advised against staying in the home without fixing its foundation.

“They’re like, ‘You should probably go,' ” said Nikki Rose, president of the Sand Lake Community Council. Now the couple and their young son are figuring out next steps.

It’s the kind of scene that will be unfolding around the region for days, as engineers work to inspect thousands of buildings and homes for earthquake damage. Engineers are using a colored system of tags -- red, yellow and green -- to communicate safety problems.

In the first few days after the quake, many structural engineers focused on critical facilities, like schools, hospitals and airports, and commercial buildings.

“I don’t know a single structural engineer that was not out on Friday looking at buildings,” said Amy Mestas, a senior structural engineer and senior associate with PDC Engineers in Anchorage....

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Here’s why some structures fell in the Alaska earthquake and others didn’t. And how we decided that.
https://www.adn.com/opinions/2018/12/04/heres-why-some-structures-fell-in-the-alaska-earthquake-and-others-didnt-and-how-we-decided-that/



...“Some of them, we can just look at the picture in the paper and say, ‘Yep, that’s why that failed,’” said Ross Noffsinger, the acting municipal building official — a job that puts him in charge of enforcing the building code.

In areas where roads cross wetlands, failure can occur when shaking liquefies soils underneath, said Kyle Brennan, who leads geotechnical engineers for Shannon & Wilson in Anchorage and is vice chair of the city’s Geotechnical Advisory Commission.

But that doesn’t necessarily mean anyone made a mistake. Construction that can withstand a strong earthquake may be too expensive for low-hazard infrastructure like roads, which are relatively easy to fix. Engineered facilities that failed may have been built to fail in a quake this strong.

In other cases, however, construction probably should have been better, especially in damaged homes. I doubt it is a coincidence that more housing damage occurred in Eagle River, where building codes are not enforced, than in the Anchorage Bowl. I’ve also heard of damage in Mat-Su, which doesn’t have residential building codes. (It’s also possible more severe shaking was a cause.)

Under Anchorage’s odd form of local government, areas can choose a menu of services. Eagle River never opted into the Building Safety Service Area, where Noffsinger’s office has authority....

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We used to live in Eagle River, Alaska.