Shake, rattle and roll.

[David Thomas]

[Jerry Adams]

I was thinking of Alaska people.  I hope all of you are doing okay.  David still has power and internet access and time to post so must be okay.

They were talking about natural gas line breaks and fires.  I was wondering if that would affect David’s butane extraction experiment : )

[David Thomas]

It felt stronger than its 7.0-ish (they’re still revising the numbers) this morning, and I’m 70 miles from the epicenter.  Anchorage is 7 miles away and had road damage – large cracks and some sink holes.

The highway from my house to Anchorage (and the rest of North America) is closed, but it is mostly just rockfall and threatening rockfall.  I suspect it will reopen later today.

I find it less nerve-racking to be in a house I built myself during the last few magnitude 7s.  I know where all the tie-down bolts are and the nailing schedule on every sheet of plywood.  Each jolts happens and I think, “Not a problem.  Nor that one. That’s fine, too. . .”  I was more nervous during a little 5.8 while being operated on.  I imagined unsterile bits of the ceiling tiles falling into the surgical field and open incision.

 

[David Thomas]

Jerry:  Shush!  It was my butane experiment blowing up that triggered the whole thing.

Yeah, some gas lines in Anchorage have been damaged.  One “upside” of global warming is 35F in late November makes power outages and any lack of natural gas less of an issue than historic weather which would be -10F to +15F this time of year.

[BlackHatGuy]

Just read about this. Hope all our Alaskan friends are okay.

[Philip Tschersich]

Didn’t even feel it in Kodiak. We had a precautionary tsunami evacuation, but that was called off after 90 minutes. I don’t know why anyone would want a house below 100′ elevation around here. You’d have to engineer scuppers into the baseboards.

[jscott]

To have done that much damage at that level of the Richter scale it must have been shallow. The Northridge quake many years ago did a lot of damage at like 7.0 or something–but it was shallow.

We can only imagine the damage if Trump had been the epicenter…

OR, this, if you prefer: we can only imagine the damage if Bill Clinton had been the epicenter…

[David Thomas]

Jeffery: Something about our local geology seems to focus the seismic waves such that certain locations get hammered far more than you’d expect from a magnitude X from Y miles away.  This was only a 7.1 about 80 miles away in 2016, but my little neighborhood had particularly strong ground movement:

I ended up with an extra wall on my property from the house that exploded from a gas leak:

two houses were burnt to the foundations and the adjacent two were total losses:

Everything on the near side of the fence is our lot.

[Rex Sanders]

Earthquake magnitude tells you roughly how much energy went into the earth. Each whole number increase in magnitude represents 32 times more energy release.

What happens to it after that depends on the kind of fault motion, earthquake depth, local geology, building codes, and bad luck. That’s why a M6.9 in one place can cause a lot more death and damage than a M7.0 in another.

USGS details on today’s quake here: https://earthquake.usgs.gov/earthquakes/eventpage/us1000hyfh/executive

Trigger warning – lots of geology jargon!

— Rex

PS – Geologists mostly use moment magnitude rather than Richter magnitude these days. It’s complicated.

[David Thomas]

I tried to post a FB video of a Jeep negotiating one of those seemingly impassable, broken, sunken roads.  Because if you have a Jeep, you live for those opportunities.  But the link didn’t work.

[jscott]

Actually, I wasn’t thinking when I posted earlier…7.1 is a strong temblor. The Santa Cruz/San Francisco 89 quake was 7.2 and it did a lot of damage over a broad area.

The Northridge quake was 6.5 or something, and I was surprised by the damage–again, it was shallow.

I hope the news is good in terms of lives and damage! Best wishes to Alaska.

[Paul Wagner]

Dave: thank you for letting us know you are OK!  In Napa a few years ago we had a 6.2 with a epicenter about three miles from our house.  It changed the way I feel about earthquakes–and I was in the big Mexico City quake in 1968 as well as the Loma Prieta in 1989–albeit farther away from the epicenter.

Let us know if there is anything we can do to help.  I know a lot of people here would jump at the chance.

[David Thomas]

Thanks, Paul, but we’re just fine.  A few hours wasted on Facebook this morning, posting updates, but otherwise, no damage, not even any inconvenience.  If I’d been flying out today or trying to get back from Anchorage, it would have taken a few extra hours.

Some commercial buildings and some homes in and around Anchorage have been damaged.  If they don’t have specific earthquake insurance, that’s a big financial loss.  Some of the roadway damage is significant, but there are any single-access routes I’m aware of that have been effected.  It might actually get our legislature to acknowledge that sometimes you have to spend tax dollars on infrastructure.  Thankfully, there appear to not have been any deaths and maybe not even any injuries to speak of.  The 7.9 I list below only had one injury – someone ran out of their wilderness log cabin, slipped on the ice and broke their arm.  A 7.9 in many parts of the world would kill 400,000 people.

My earthquake cred to date:
Various medium-sized quakes as a kid and college student in the SF East Bay.
Loma Prieta (“World-Series Earthquake”), 1989, 6.9 – I drove through the Cypress Structure earlier that day (where 42 people died) and rode out the quake in a building on landfill in (formerly) Richmond Harbor.  It felt like being a boat on in a bowl in a bowl of Jello, being shaken.  Then I went home and watched the Marina District burn in the distance, across the Bay.
Nisqually Earthquake, 2001, 6.8.  We’d moved from Seattle to Alaska by then, but we still had our 1910 Craftsmen-style home in Capital Hill maintaining it as a rental and dropped $8,000 on a new chimney after that quake.
Denali Quake, 2002, 7.9 – most memorable because our Slovakian au pair, who’d NEVER experienced any quake got to ride out a decent sized one.
Old Illiamna Quake, 2016, 7.1 – 80 miles away, but somehow focused on our area.  Gas leaks we could smell, neighbors’ houses exploding and burning to the ground, mandatory evacuation (we were already leaving).
Gulf of Alaska, Jan 2018, 7.9 – generated tsunami warning, but it would take 5 hours to get to us.  I studied up on tsunamis a lot that night and watched posts from Kodiak and Homer (who would get hit before us).  Turns out a tsunami would travel up Cook Inlet to our house at about 80 mph.
Anchorage Earthquake, Nov 2018 (today), 7.0.  Apparently the greatest financial loss in Alaska (that has a 7 or 8 EVERY year since at least 1900) since the 1964 Good Friday quake – which was the largest in recorded American history and second largest in recorded world (ohh – another aftershock as I type this.  Edit: reported as a 5.1 about 80 miles away) history.

Hours after the Loma Prieta Earthquake, my mother asked my grandmother what she thought of the earthquake.  She responded with stories of being 7 and living in San Francisco in 1906, watching downtown burn off in the distance for 3 days and 3 nights and the relatives from downtown coming out to stay with them in the “country” (now the Sunset District).  She was 90 then and had Alzheimers, and while she couldn’t remember that afternoon, she could clearly remember the big event of her childhood, 83 years before.

[Jerry Adams]

wow, I’m staying away from David

From the news it looks catastrophic. Wall to wall coverage of that collapsed road with the stranded car. I like how they put ramps in place so it could drive out. That would have been pretty impressive to experience that from the perspective of that car driver.

[jscott]

David, an early memory for me is feeling the 1964 Alaska quake while at school–in Snohomish, Wa. We felt it pretty good too.

[DAN-Y]

Get a jeep David :-)

[Jerry Adams]

Thata’s pretty good. I bet that stranded car could take the same exit route out of the collapsed area, that didn’t look too difficult

[David Thomas]

I was inspired to stay home and bake cookies.
But other people got out and drove around.

[DAN-Y]

Your cookies look like they were influenced by the quake

[David Thomas]

DanY: That was the point with the cookies (a style my grandfather baked).

Correction: there was some road damage locally.  One of my co-conspirators in the epic father-daughter backpacking trips (we’re planning on Denali NP this summer) invited us over for a little geology field trip with the kids, 100 yards from his house where a road descends to a State Park boat launch:

We’ve also got a meme floating around today patting DOT on the back:

Which is especially striking to those of us from NoCal.  How many decades did it take to deal with the Bay Bridge after Loma Prieta and it’s still not right?

[DAN-Y]

I like it….chest deep in local geology 

72 hour geology make-over…compliments to your DOT

[Ethan A.]

David and Philip, Relieved to hear you are OK. The speed of rebuilding is astonishing especially after what I’ve seen in California.

[jscott]

Ummm, with all due respect to Alaskan’s get er done spirit…building a new bridge while tearing down the old one was just a smidgen more complicated than that road repair.

[Author]

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