How Earthquake Proof Are Your Homes? (Anchorage, Fairbanks: house, tornado, live)

[Oplimme]

So I get it, there's quite a few earthquakes around and in Alaska.

I'm just curious - how earthquake proof are your homes?

[gobrien]

Most of the earthquakes, if they can be felt at all, just shake so little it feels like someone bumped the furniture. I don't know anybody who has an earthquake proof house, but I have been in a 13 story building in Anchorage built on rollers so that it can withstand an earthquake. It is quite an experience to be in a minor quake in that building.

[Rance]

My house is insulated with urethane foam. It's rigid and tight as a drum. Of course proper nailing for shear strength helps. It's still standing after 30 years!

I'm not sure what it would do being a 2 story place if a/the big one hit.

[roadfamily6now]

My house is not really earthquake proof but it was here during and after the last big one.

Now the furnishings are NOT earthquake ready. Well, except our big TV, that sucka ain't going no where.

[RayinAK]

Originally Posted by gobrien

Most of the earthquakes, if they can be felt at all, just shake so little it feels like someone bumped the furniture. I don't know anybody who has an earthquake proof house, but I have been in a 13 story building in Anchorage built on rollers so that it can withstand an earthquake. It is quite an experience to be in a minor quake in that building.

We have had some in fairbanks and vicinity that have shaken homes for a for seconds if not minutes. The last one i remember happened around ten years ago in the middle of the day.

[gobrien]

I lived in Tornado Alley for 13 years and was surprised by how few storm cellars there were.

[Floyd_Davidson]

The tectonic plate from the Pacific Ocean floor that is moving northward and colldes with that of Alaska slides under the Alaskan land mass south of the coast, under water. It goes progressively deeper until it is pushing virtually into the earth's magma. The farthest north it reaches is the south side of the Brooks Range.

Hence near Barrow there are no major faults and earthquake bracing in buildings is not required.

In Fairbanks the effects of major quakes are vastly different that farther south. Quakes in the range of 6 or 7 do happen, but anyone even 30 miles distant doesn't feel much. The tectonic plate is thousands of feet below the surface, and in between is solid rock. A quake is like having a pile of children's wood blocks and moving one of them far enough to let another fall to a new position. It goes clunk, and that's it. A big one that moves more blocks just goes clunk-clunk.

In Anchorage even relatively small earthquakes (3 to 5) cause a lot of movement, and a big one at 6 or larger can go on and on and on. The reason is because that tectonic plate is just below the surface hundreds or a couple thousand feet, and between the surface and the moving plate is gravel or crushed rock mixed with mud. It's been likened to making a big bowl of jello and setting it on a couple of dinner plates and then moving one of the plates. The jello starts quivering when the plate moves, and doesn't stop for a relatively long time. (I recall reading a description once where the 1964 quake caused one family to run in and out of their cabin 2-3 times over several minutes as it seemed safer here or there, while the cabin disintegrated and their yard had huge gapping fissures forming.)

And Anchorage quakes aren't much compared to Adak Island! Out there they have to tie everything together, and then tie it down. Otherwise it would crumble to pieces in a quake tomorrow morning and lterally blow away in the wind that afternoon.

[1stimestar]

I must have been sitting right on top of the last one we had a couple of months ago. This is just a rental. I wouldn't choose sheetrock personally. While it was only reported as a 4.something, it FELT like the cabin had been knocked off its foundation. It was accompanied by a loud boom/bang. A few days later, these started showing up so I guess it was as bad as it felt.






This one goes from the window edge all the way to the corner.

You can read about it on my blog, I think the second post down.
Alaska, The Madness

[Floyd_Davidson]

Originally Posted by 1stimestar

I must have been sitting right on top of the last one we had a couple of months ago. This is just a rental. I wouldn't choose sheetrock personally. While it was only reported as a 4.something, it FELT like the cabin had been knocked off its foundation. It was accompanied by a loud boom/bang. A few days later, these started showing up so I guess it was as bad as it felt.

Given that kind of damage, and only a 4, you probably were relatively close to the epicenter. The "loud boom/bang", also often described as a "big thunk" is pretty much the characteristic of earthquates in the Interior. It's movement of a lot of solid rock, and it just goes from here to there (with a little, but not much, reverberation). Down in Anchorage an earthquate more than 50 miles away at that strength can cause reverberations for several seconds before it subsides.

Edit: I took a look at your blog (which I've enjoyed previously), and tried to figure out where you live (miles north of the airport was all I could figure out, but that's close enough) and figure out when that earthquake happened.

Heres a description of a quake on Wednesday October 13th that is almost certainly the one you referenced.

"The 3.42 magnitude quake was centered 7 miles east of Fox and struck at 12:10 a.m. It was at a depth of 2 miles. Many Goldstream Valley residents reported feeling it, but no damage has been reported."

So it is likely you were easily within 20 miles, and maybe more like 10 miles from the epicenter. Note that it was 2 miles deep, in solid rock, so there isn't much difference between being directly above it and being 10 miles distant.

[Rance]

Sheet rock earthquake cracks are easy to fix! Get you a tube of toothpaste and fill in the cracks!