Comments on: Earthquake in Alaska

By: Retired Engineer

Retired Engineer — Wed, 05 Dec 2018 00:56:09 +0000

According to Wikipedia, the factor is 31.6, not 10. So a difference in 2.0 magnitudes is 1000.

By: Kate

Kate — Sat, 01 Dec 2018 19:51:11 +0000

Actually, my engineer husband says my estimate of a Richter scale 9 quake being about 100 times stronger than a 7 quake is about right (not 1000 times). Every point on the logarithmic scale is ten times the previous one; 10 x 10 = 100.

By: Ray

Ray — Sat, 01 Dec 2018 16:17:59 +0000

I will always remember the 1964 Alaska Good Friday earthquake. I was on Johnston Island, southwest of Hawaii, and we were apprehensively waiting to see if there was going to be a tidal wave. Fortunately there wasn’t one because the highest point on Johnston Island is about 8 feet above sea level.

By: ColoComment

ColoComment — Sat, 01 Dec 2018 16:11:02 +0000

Listen to professionals at work (ATC at Anchorage airport):

https://www.youtube.com/watch?v=o80cNJ_XhX0&feature=youtu.be

By: Kate

Kate — Sat, 01 Dec 2018 12:33:33 +0000

Oh, darn it, I knew I’d mess up the Richter scale. Thanks for correction.

After visiting Alaska, I began reading about the Cascadia subduction zone. If there’s a repeat of the quake and tsunami of 1700, and there could be, Seattle would be far, far worse off than Anchorage.

By: FOAF

FOAF — Sat, 01 Dec 2018 11:06:35 +0000

“one hundred times less powerful than the ’64 quake”

I believe it is actually one thousand times less powerful, assuming a 2-point difference on the Richter scale (9 to 7). The Richter scale is logartihmic and each point represents an increase of approximately 30 times the release of energy.

By: FOAF

FOAF — Sat, 01 Dec 2018 11:02:17 +0000

“If Seattle — where I live now — suffered an equally-strong quake at similar depth and distance, we would be far worse off than Anchorage today.”

I probably need to be fact-checked on this, but my understanding is that Seattle is in fact in danger of a truly massive earthquake, i. e. around 9 on the Richter scale comparable to the Anchorage temblor or the one that hit Japan a few years ago.

By: Bryan Lovely

Bryan Lovely — Sat, 01 Dec 2018 08:20:24 +0000

I was born in Anchorage a year after the ’64 quake and grew up there. I predict that other than a few sections of road and maybe a bridge or two, most of the damage will turn out to be superficial — lots of cracked drywall, dropped ceiling tiles, and burst pipes, but very few gas fires or collapsed houses. After the big quake, building codes were taken VERY seriously and we all had earthquake safety drilled into us in school every year on the anniversary. (Although I don’t know if they still do this.) There will be no repeats of the Turnagain neighborhood (now Earthquake Park), which was built on clay that liquefied and slid into Cook Inlet.

My dad’s apartment building — of no particular quality in an older neighborhood — suffered no serious damage except for the insufficiently-secured carport collapsing onto his car. My best friend’s office building downtown sustained some damage but his home in the foothills did not; likewise for my dad’s lady friend.

If Seattle — where I live now — suffered an equally-strong quake at similar depth and distance, we would be far worse off than Anchorage today.

By: Kate

Kate — Sat, 01 Dec 2018 01:35:07 +0000

We were fascinated when we were in Alaska in 2015 by the still-evident damage in the Turnagain Arm from the great 1964 earthquake. Good to know there appear so far to be no deaths from this one, one hundred times less powerful than the ’64 quake. But I’ve seen photos of highways broken into chunks with sunken portions from the quake today, so damage will be extensive.

By: FOAF

FOAF — Fri, 30 Nov 2018 22:33:46 +0000

The 1964 earthquake there was one of the largest ever recorded, according to the USGS exceeded only by an earthquake in Chile in 1960. One of only a handful to reach 9 on the Richter scale.