...and the ground still shakes.
We got a good 4.0 several days ago just to remind us that tectonic
plates laugh at us and the earth can shake us off like a dog shakes
off fleas.
A year later and about 10% of the homes are still not inhabitable in
Eagle River, (population 30,000), with some neighborhoods having over
30% of the homes red flagged and/or condemned. Several on our private
street were red flagged. Every single one of our houses on our street
shifted downhill 1-5 inches and all experienced various levels of
structural damage--some quite extensive. $150,000-200,000 in damages
is a pretty common amount. Ours has over $100,000 and counting and
counting and counting... (fortunately, we rent!!!)
Eagle River got hit the hardest as we're not only closest to the
epicenter, but directly east of it and got the bulk of the energy
release as it was highly directional. The business district was
decimated, with numerous structures destroyed or damaged beyond
repair. Things are slowly coming back to normal--kinda like during a
recession when you have a number of stores closed. At one point or
another, about half of the businesses have been closed for repairs or
moved to other locations entirely. It was really misleading as
structures had visible damage, but passed inspection, only to be
condemned later once repairs were started and structural damage was
found. (like steel beams broken, or voids under foundations).
Due to the specifics of this earthquake, two or three story structures
were affected the most. And Eagle River also experienced more damage
because it is built on either glacier till or rock slides. Entire
neighborhoods moved en-mass, including ours. Some houses were built on
ground not properly prepared, and nearly all of those are bulldoze
specials.
The USGS has posted some interesting computer simulations on youtube
of several high-rise buildings in Anchorage. The Atwood building is
right downtown, while the Frontier and BP buildings are in midtown. (I
currently work a couple blocks away from the Frontier building). You
can see by these YouTubes just how fierce the east-west motion was and
how the resonance really got some of these buildings doing some odd
things. Gotta love steel.
Atwood Building (November 30, 2018)
https://youtu.be/9MlvLdnwLY4
Frontier Building (November 30, 2018)
https://youtu.be/BXhU5oeIgs0
BP Building (November 30, 2018)
https://youtu.be/NKOdkmrjYWA
For comparison, here is the Atwood Building in the January 24, 2016
earthquake that had a very different motion. The building did get
signifiant changes to the shear wall structure which changed the way
it moves as it was designed to twist in order to dampen movement.
https://youtu.be/Nt0m5JWa62w
AK Schnozz
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