r/IAmA • u/WaQuakePrepare • Oct 19 '22

We're Pacific NW U.S. earthquake experts ready to talk about tsunamis, earthquake early warning and more Science

EDIT: We are pretty much done! Thanks everyone for the great questions. We have some folks that could check in later if we didn’t get to your question or if you discover us later today but the answers won’t be right away. Remember no matter where you are, we invite you to drop, cover and hold on at 10:20 am Thursday. Learn more at shakeout.org

Oct. 20 is the Great ShakeOut, where millions of people across the country practice earthquake safety and drop, cover and hold on under a sturdy object. Today, we have experts in Washington state and Oregon talking about ShakeOut, earthquakes and we can even touch on Pacific Northwest volcanoes. For instance, did you now it’s possible to now get a warning on your phone before an earthquake strikes? It’s called the ShakeAlert Earthquake Early Warning System.

We are a team with a variety of expertise particularly in the Pacific Northwest including: earthquakes (science/physics, monitoring, protective actions, preparedness), tsunamis (tsunami safety, hazards, modeling, preparedness, and recovery), structural engineering/building performance and emergency preparedness.

PROOF HERE. More proof here.

From Washington Emergency Management Division:

Brian Terbush

Elyssa Tappero

Mark Pierepiekarz, P.E., S.E.

Hollie Stark

Dante DiSabatino

From Pacific Northwest Seismic Network:

Bill Steele

Dr. Renate Hartog

Dr. Alex Hutko

From Washington Department of Natural Resources (Washington Geological Survey):

Corina Allen

Daniel Eungard

From Simpson Strong-Tie (Structural Products and Solutions including Earthquake Retrofits):

Emory Montague, S.E.

From Oregon Office of Emergency Management:

Althea Rizzo

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26

u/cferris17 Oct 19 '22

Are people on the coast screwed when the big one hits? Let's say you are on the coast when it happens, is there any hope for survival?

46

u/WaQuakePrepare Oct 19 '22

There absolutely is hope if you're on the outer coast. Depending on where you are when the "big one" hits, you might be near natural high ground, artificial high ground (one of our vertical evacuation structures), or otherwise able to get yourself to safety if you're prepared in advance and ready to act. There are many stories from Japan, Indonesia, and Hawaii of people surviving absolutely unbelievable circumstances during tsunamis, even people who were right on the beach. The more prepared you are, the higher your chances are that you will not only survive but be able to get yourself to safety after.

- Elyssa

16

u/windando5736 Oct 19 '22

artificial high ground (one of our vertical evacuation structures)

What is a "vertical evacuation structure"? Is that just a sciencey way to say "tall building/skyscraper" so just heading up the stairs in any tall building will do, or are there certain buildings in CA/OR/WA that are designated as special "vertical evacuation structures"? If the latter, are they just certain reinforced buildings that are used as apartments/offices normally, or are they just empty tall buildings just sitting around just in case a tsunami is coming? Or are they something else entirely?

I guess the TL;DR here is how would a person identify the nearest "vertical evacuation structure"?

23

u/WaQuakePrepare Oct 19 '22

Vertical evacuation is relatively new for our coast and are designed specifically to withstand a tsunami. Here is an example of one that opened recently.

1

u/12-32fan Oct 19 '22

Do the vertical evacuation structures have a way to help those who are not able to walk?

15

u/WaQuakePrepare Oct 19 '22

The two in WA don't have anything like ramps built in, but that's something people are factoring into future designs. The Ocosta structure does have those emergency carry chairs firemen use (sorry, don't know the technical term) and the Shoalwater Bay Tribe is looking into something similar for their freestanding tower (the stairs for that tower are also quite shallow). Fortunately if you're coming to the tower, there will be a LOT of other people there too, and we know our communities will come together in times of disaster, so it's unlikely someone will be left behind just because they can't make it up the stairs. That's not a good fix, of course, so options are being looked into on a tower-by-tower basis.

- Elyssa

1

u/Seattleopolis Oct 20 '22

What if you just set out to sea immediately to roll over the waves before they come inland and break?

8

u/BasedBarry Oct 19 '22

Probably have a good amount of time to make it to high ground (OR / WA coasts are full of areas above the tsunami line) if you react to the shaking, it's the bridges and structures in the PNW that are historically not up to code, that's changed recently but so much relied upon infrastructure is not earthquake ready. The low lying houses on the coast will be wiped out, it'll be a huge tsunami but if you watch videos of the Japan Tsunami, you can see high ground will save you even in a 9.0

9

u/Portland Oct 19 '22

How much of the coastline and surrounding hills will experience liquefaction?

If there’s serious landslides and damage to roads, it might be difficult for people to easily reach Tsunami safety zones, particularly in low lying communities, Warrenton & Seaside for example.

6

u/BasedBarry Oct 19 '22

I figure Long Beach and everything around it would have a nearly impossible time escaping down to Cape Disappointment, it's essentially a peninsula. As far as rock slides, I can see a lot of the sheer cliffs breaking apart but generally down the OR coast at least there's stable hills behind the coastal towns. Cannon Beach is one of those, Seaside Ecola state park just to the south which is all above the tsunami line as well

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u/WaQuakePrepare Oct 19 '22

You can find a liquefaction susceptibility study for Long Beach Peninsula at http://www.dnr.​wa.gov/Publicat​ionsger_ri37_l​ongbeach_liquef​action.zip and for Aberdeen, Hoquiam, Cosmopolis at https://www.dnr​.wa.gov/Publica​tions/ger_ri36_​aberdeen_liquef​action.zip.

-Daniel (WGS)

13

u/WaQuakePrepare Oct 19 '22

WA DNR has liquefaction data on their interactive Geoportal, which is a great way to see if you live in or near a liquefaction zone:

https://www.dnr.wa.gov/geologyportal

- Elyssa

2

u/Crocolosipher Oct 19 '22

I've excited these and haven't seen it, I'm probably doing something wrong - What map is the liquefaction data on specifically?

5

u/WaQuakePrepare Oct 19 '22

The Geoportal isn't the most user-friendly system. If you go to the Natural Hazards map (direct link below) and open the table of contents, you'll find liquefaction susceptibility under earthquakes and then ground response.

https://geologyportal.dnr.wa.gov/2d-view#natural_hazards?0,0,0,0

- Elyssa

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u/WaQuakePrepare Oct 19 '22

If you need help after this thread slows down, you can always reach out to our team at Public.Education@mil.wa.gov!

1

u/Fronesis Oct 20 '22

As somebody that lives in West Seattle, I fully expect to be on the West Seattle Bridge when the big one hits. No way we just get another forty years out of that bridge with no problems. That's not how our luck works.