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

how scared are you/should we be for the cascadia fault? i guess i should also ask, is there current procedures in place for the movement of troops to assist with survival after a large earthquake? such as the use of navy ships for medical/desalination services, aswell as air force combat communication/rapid deployment for the building of airfields to start delivering supplies to the most damaged communities?

We are well aware that this is a major hazard for the entire Pacific Northwest, and you need to be aware of it. The understanding that if you live in this area, even if you're on the far eastern side of WA, OR, or British Columbia, an earthquake and tsunami on the Cascadia Subduction Zone (CSZ)would dramatically change your life, just in terms of damage to infrastructure (Power systems, roads, water/wastewater, supply chains ... everything).

The Earthquake itself, and the following tsunami will be extremely dangerous. But the message we really want to emphasize - you CAN survive these events. Everything you do now to get prepared for them significantly increases those odds though.

Knowing how to protect yourself during 5 minutes+ of intense earthquake shaking is critical. ...consider that you'll need to know this for months of (smaller, but still dangerous) aftershocks, too.
Knowing whether you're in a tsunami inundation zone, and how you'll get to high ground - absolutely vital.

A potential earthquake on the CSZ is just a reality of living here. There's a 15-25% chance it will happen in the next 50 years. There's also a chance it won't happen in our lifetimes. But if there's a 25% chance of rain... packing a raincoat is the smart thing to do.
I recommend visiting https://mil.wa.gov/earthquakes to get started with some earthquake preparedness tips, which will link to a number of other earthquake preparedness resources in the State. Another critical partner to get you started on your preparedness journey - find your local emergency management office (at the City, or County level) for tips on what issues you should be prepared for in your area.

-Brian

Raincoat not an umbrella, confirmed actually PNWer

Us transplants can learn!
-Brian

I read this article about this back when it came out. It's stuck with me all these years. Any comments on it?

The New Yorker "Really Big One"

Not gonna lie that was part of the decision for us to leave the PNW. (The other half being housing costs)

There was such a backlash against the original article for being all doom and no preparedness that they wrote a followup that you should also read https://www.newyorker.com/tech/annals-of-technology/how-to-stay-safe-when-the-big-one-comes

You didn't answer any of those questions about government preparedness and instead covered only personal responsibility. Duke17776 wanted to know how the government would respond. So I will again ask - what have local/state/federal agencies/orgs done to prepare for this potential event?

In June, we did an exercise called Cascadia Rising. It’s the second time that state agencies teamed with local, tribal and federal governments to figure out how we would respond to a big disaster. Simply put, in a large Cascadia earthquake, you will be on your own for two weeks or longer. Help will come, but it will take a while to arrive. You can look at these slides and see how we focused on mass care services. And you can can look at these slides and look at the transportation problems. This is a public website. The videos are all posted. The slides posted. And when the after action report is finished, that will be posted, too. This is the after action report from the 2016 exercise we did.

One of the things that's always puzzled me since visiting the Oregon coast are all the tsunami warning signs that tell you to head for high ground or inland if you feel an earthquake, some of which point to an evacuation route.

How much actual time is there to get to high ground once an earthquake hits? Is this a "drop everything and run, and maybe some of you will make it" thing, or something you have time to grab a few possessions and take a nice leisurely stroll for? The signs don't exactly make it clear whether this is a thing where seconds (and good cardio) matter or not.

The arrival time depends greatly on where you are with the earliest arrival to Washington's coast from a Cascadia event being roughly 15 minutes and places in the south Puget Sound as long as 4 hours. For local crustal faults such as the Seattle Fault a generated tsunami could arrive to the region surrounding the fault zone in minutes to tens of minutes. You can find arrival times on our hazard publications available at https://www.dnr.wa.gov/programs-and-services/geology/geologic-hazards/tsunamis#tsunami-hazard-maps.

-Daniel (WGS)

I feel like more of the discussion about evacuation should really emphasize the 15 minutes. 15 minutes is not a lot of time. I would guess most people couldn’t get more than a mile and a half in 15 minutes. If I’m at the beach would 1.5 miles away be enough to keep me safe?

That highly depends on the location of interest and how far away natural high ground is. For much of Oregon and Washington there is adequate time to walk/run out of the hazard area provided the evacuees begin their evacuation as quickly as they can.

For some locations such as in southwest Washington, natural high ground is not close enough to evacuate to before the waves arrive. In these locations Vertical Evacuation Structures (VES) such as those built in Westport, Shoalwater Bay Tribe, and Newport provide alternate evacuation options. Efforts are ongoing to build more structures elsewhere in the which my friends at EMD can elaborate on further.

-Daniel (WGS)

It depends on how far away the earthquake that triggers the tsunami is.

Regardless, if you hear a siren notifying you that a deadly wall of water is headed your way, why would you go home to grab possessions and take a leisurely stroll? Stuff can be replaced, your life can't. When a sign says to head to a safe zone when you hear a siren or feel an earthquake, you head to the safe zone immediately.

The idea of going to a third location wasn't even in my imagined range of options. I was thinking more along the lines of "blind, frantic panic, knowing you most likely won't make it" or "pick up your stuff and pace yourself for climbing a hill without hurting yourself."

We definitely don't want you to hurt yourself, but we do want you to hurry. That's why it's important to have your go-bag already packed, that way you don't have to panic about getting ready to go. If you've practiced your route, or even just looked it up on the map if you're visiting, that cuts down on the panic. You have time to take a breath and clear your head - that will save you where panic might put you in danger.

- Elyssa

Is shakealert an app or does it go through the emergency alert system? Will there be a test pushed to phones tomorrow?

Good question! We'll try to make this less confusing for you:
ShakeAlert is the name of the USGS's earthquake Early Warning system in the U.S., which detects earthquakes when they happen, and sends messages to areas that will shake, with the intention of getting that messages to places seconds before the earthquake shaking arrives:
In Washington, there are 3 ways ShakeAlert can send these warnings to your mobile phone:
- Wireless Emergency Alerts (Like AMBER Alerts)
- A built-in Alerting system in the Android phones
- By Downloading the free "MyShake" app.

All three of those systems are part of "ShakeAlert." If you'd like more info on the 3 systems, and how you can make sure they're working on your mobile phone in Washington, some detailed instructions are available at https://mil.wa.gov/alerts.
MyShake is the only downloadable app that works for sending earthquake early warnings in Washington. The MyShake App is also the only one of these three methods that is sending a test message for the ShakeOut Drill tomorrow (10:20 a.m. on 10/20).

Hope this helps! - Brian

I get amber alerts without having done special on my phone; will I get ShakeAlert automatically or do I need to download that app?

Wireless Emergency Alerts are typically on by default on your phone - but we recommend checking to make sure they're enabled if you want these as your earthquake early warning source.
Same with Android's earthquake alerting system (on by default, but we recommend you check.)
If you have an iPhone, we recommend downloading the MyShake App for warnings, because it is faster than the WEA messages. Since you're only likely to get seconds of warning, faster is better.
You can learn how to enable these alerts at https://mil.wa.gov/alerts#ShakeAlert
-Brian

This is great, thank you!

Couple questions:

1. I’m in Vancouver and have downloaded the MyShake app. Will i still receive alerts?
2. I’m a developer and would like to build a plug-in for home assistant which is software for automating your home. Is there a public API or a way to get access to the raw earthquake/tsunami alert data?

Yes! We hope you do. Learn more about the test here https://myshake.berkeley.edu/faq.html#mobile-app

USGS controls who gets the data. Find them here https://www.shakealert.org

Are there any warning apps for California residents that you know of?

MyShake is for Washington, Oregon and California.

Yup! That one works in California, too - which is nice, if you ever travel up and down the coast it works in all 3 states!
-Brian

When I visited Cannon Beach, Oregon years ago I remember driving by the high water mark "safe zone" on the highway and remembered thinking it would be impossible to get there in with only a 15 minute warning from the Tsunami sirens. Would everyone in Cannon Beach actually be screwed if a Tsunami hit or are there other mitigating factors (e.g. it might take more than 15 minutes for the Tsunami to hit, or you don't need to be that far away from the beach to increase your chances of survival)?

Cannon Beach will be a mess. It has become so overcrowded by tourists in the last 10 years. There is almost always a big traffic jam and people driving around looking for parking spots when the weather is even remotely nice, and sometimes even when it’s not. I would imagine that a lot of people won’t be able to make it to the safe zone in time.

Yeah that was my main thought - the road would be gridlocked, making it impossible to get to high ground in time unless you have a motorcycle. But if it's actually going to be a shit show shouldn't the state be stepping in to do something? Like widening the road from the town to the high water area?

This gridlock is why we emphasize pedestrian evacuation for tsunamis, especially local ones. If the roads are passable (big emphasis on IF) we want to leave them open for first responders and people who physically can't evacuate on foot. It's a work in progress, lots of people assume they'll drive... but we're trying! And in places where even pedestrian evacuation isn't enough we're building artificial high ground in the form of vertical evacuation towers. Washington has 2, Oregon has 1, and we're working to build more all the time.

- Elyssa

The Department of Geology and Mineral Industries (DOGAMI) has worked to provide all their evacuation and hazard information on the Nanoos website. You can find information for Cannon Beach there! http://nvs.nanoos.org/TsunamiEvac

-Daniel

We go to Cannon Beach quite a bit and we just assume we'll be waking/running to high ground, not driving.

Based on the models of potential damage to roads that close to the fault, we assume that you're making a good assumption.

-Brian

Should everyone buy earthquake insurance for their home? Especially those that are living in new construction homes/townhomes (I.e 2018+).

When we purchased our home and looked into insurance, earthquake insurance was prohibitively expensive and we were told it didn’t really make sense to get it.

As you insinuated, it's a personal choice that really depends on factors related to your dwelling, local risks, and wallet. What I CAN say is that if you DO have any sort of insurance, even renters, be sure to have your information in your go-bag so you can begin filing any claims ASAP. Claim information, photos of valuables, ID numbers, serial numbers of electronics, etc - if your stuff is lost in a flood, fire, or under the rubble of your house, it's too late to tell your insurance agency what it looked like beforehand.

FEMA's Financial First Aid Kit is a great resource for gathering this information together in one place: https://www.fema.gov/emergency-financial-first-aid-kit

- Elyssa

For residents of Northwest Washington islands such as Whidbey, Camano, Orcas, and San Juan; how do you recommend preparing for potential future earthquakes and/or tsunamis? Is there any specific risks that affect island residents more than mainland ones?

Looks like we tried to answer this one and the internet ate it, so attempt #2! In addition to preparing like everyone else, island residents (and visitors!) need to bear in mind that a disaster could leave you either isolated even more than normal (bridges down, ferries inoperable, etc) or trapped on the mainland. With some islands having few grocery stores and other vital amenities, you need to be ready to go without for a prolonged period of time or have a plan in place to let responders know if you absolutely need to get off-island (say for medical care). If you travel off-island for work, make sure the go-bag in your car is particularly robust - you may be relying on it for longer than you intended! Lastly, have a plan for anyone stuck behind on the island if you can't get back. Who will feed your pets? Who can check on your house? Etc.

- Elyssa

I think island residents have the same risks as coastal residents from tsunami and storm surge. The earthquake shaking risk is similar as well (although the seismologists on here with me might have more specifics for your area). Preparing for the next earthquake involves having a plan, getting your supplies together, and evaluating the vulnerabilities of the structure you live in. If it was built relatively recently, it will be to more modern building codes. For homes built before 1985, you may want to have them evaluated and consider a retrofit. Here's some more information.

~ Emory (Simpson Strong-Tie)

Biggest threat in terms of human deaths: Cascadia fault, Mt. Rainier, or Seattle fault?

To be frank, Cascadia. The tsunami is a major threat to our outer coast communities, much more than Mt Rainier (for which we would most likely have more warning for evacuations) or the Seattle Fault (much lower probability than Cascadia). This is why we are working hard to get vertical evacuation structures built on the outer coast where high ground isn't close enough for folks to reach before the first waves of a Cascadia tsunami arrive.

- Elyssa

Could an earthquake set off Mt Rainier or Hood?

No, though volcanic activity can be accompanied by earthquakes (though not on the scale of Cascadia). Here's a good resource for here in WA:

https://mil.wa.gov/volcano

- Elyssa

Lahar triggered by an earthquake.

The Osceola mudflow was ~5.7k years ago and buried what is now Auburn, that's a real monster. The Electron was ~500 years ago and didn't quite reach Puyallup. A flow like the one that made the Sandy River sandy might mean having to evacuate and then rebuild much of Troutdale - bad, but not exactly the end of the world. So lahars, as awesome as they are, don't seem as much to fear as subduction zone quakes, which shake the crap out of everything every half millennium or so. Some info.

Good info about historical lahars, and thank you for sharing, but just have to point out:
Lahars are THE most dangerous hazards from Washington's 5 active volcanoes, and they need to be respected, and those in lahar hazard zones need to understand how they'll be alerted, and their evacuation routes - just as much as those in tsunami hazard zones.
For both hazards, the only way to guarantee your survival is to not be there when it arrives - That Electron Mudflow that Orting is built on top of: that is tens of feet of mud, and that's just the sediment part that remained behind after this massive wall of mud and debris moved through.

For hazards it is critical to know what to expect in your area, how you'll get alerted, and what to do/where to go when that alert arrives.

-Brian

The LA times had an article about making an earthquake preparedness kit and had a series about different aspects of an earthquake and how to prepare for it. Then they put it behind a paywall.

What free resources should we be aware of to help us prepare?

Excellent question. We want you to have easy and free access to all our preparedness information, including building a kit for earthquakes or any disaster.

You can start at mil.wa.gov/preparedness

But also check out hazards-specific information at mil.wa.gov/tsunami and mil.wa.gov/earthquake

I also always encourage people to reach out to their local (city or county) emergency management agency for site-specific maps, information, and contacts.

-Hollie

Are there signs in particular you guys look for or expect to telegraph the Big One is coming? Earthquake swarms? Dogs acting weird?

Or do you think you'll be as surprised as everyone else, if and when it happens?

Bonus question: which of you have it on your 2023 bingo card?

While we wish there were a telltale sign that an earthquake is coming there is no magic ball (or dog kennel) that can predict earthquakes. Earthquake swarms can be a sign that a fault is moving and they may be foreshocks to a bigger event. The best tool we have now is ShakeAlert/earthquake early warning, which may give a few seconds to minutes of warning before an earthquake happens: https://www.shakealert.org/

get the myshake app on your local app store to sign up for these alerts. https://myshake.berkeley.edu/

-Corina, Washington Geological Survey

Just to add - it's not just MyShake - there are 3 ways to get ShakeAlert Earthquake Early Warning in Washington on your phone.

For example, if you have an android phone - there is a built-in earthquake alert system (no download needed) that's just as fast as MyShake.

Learn about the 3 free ways at https://mil.wa.gov/alerts#ShakeAlert

-Brian

Hi PanickedPoodle! Unfortunately, there is no way to predict earthquakes. That said, the tiny probability of a large earthquake happening at any one particular time increases a tiny bit when there is an earthquake swarm due to stresses in the area changing. However, that effect is so small it isn't actionable, i.e. for us mere mortals all we can do is be prepared and make sure to have the Early Warning notifications activated on your phone (and download an Early Warning app if you haven't yet). Early warning tries to warn ahead of impending shaking when an earthquake has already started. Depending on where you are in relation to the epicenter, you may actually get a heads up that way so you can drop, cover, and hold on! -Renate

People in my social circle keep bringing up that the “big one” will cause Mt. Rainier to erupt. Is that accurate? It seems like the “big one” and a volcanic eruption might be 2 different things.

Hi! You are right, they are different things! However, it is conceivable that, if Mt. Rainier is already close to an eruption the shaking from a large earthquake could disrupt the system enough to trigger activity. However, as said, only if the volcano is already "primed". -Renate

Speaking from my limited experience from interacting with people who live in the north west, I've noted that several were not even aware that a subduction zone exists (or even those lone Cascade mountains are volcanoes.)

How often do you have to explain or educate communities about the danger of the subducting Juan de Fuca plate?

Hello, we all work with local communities, emergency mangers, tribes, schools, and anyone who will listen about these hazards. Getting the word out can be tricky, but with events like this and webinars we put together we are slowly but surely making a difference and educating people. WE usually give about 1-2 presentations a week to different interest groups.

-Corina, Washington Geological Survey

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?

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

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"?

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.

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

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.

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

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

You can find a liquefaction susceptibility study for Long Beach Peninsula at http://www.dnr.​wa.gov/Publicat​ions\ger_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)

If the Big One hits off the coast of Oregon/Washington, will a Tsunami travel up the Columbia River and how far will it reach?

Hello, yes a large earthquake on the Cascadia Subduction zone is expected to cause a tsunami that would travel up the Columbia River. The Oregon department of geology and mineral industry did a great study looking at the potential impacts: https://www.oregongeology.org/pubs/sp/SP-51/SP-51_report.pdf

-Corina, Washington Geological Survey

Could you summarize? It’s an 83 page paper 😅

Just some light reading right?

All jokes aside u/crojohnson was correct that the most significant impacts on the CR will be in the lower estuary with Tongue Point being a place where the tsunami will generally decrease in severity from very dangerous to just dangerous, then again dropping from dangerous to a maritime specific hazard at Longview. Past Longview the wave can be tracked all the way up the the Bonneville Dam analytically, however the amplitude is in the centimeters which is non-significant from a hazard perspective.

-Daniel (WGS)

How should i account pets into the practice to better prepare? I have two good bois but they are big and heavy to carry alone and I assume in a real disaster they will be acting more frantic than a practice run.

This is a great question for anyone who has furry or feathery friends. We can't predict how they will behave in an actual event, but practicing your plan does help. Try practicing your drill or evacuation walk at different times of day and - if you are feeling really adventurous - do it during inclement weather. Make sure to have photos of your pets stored on a drive or on a cloud application in case you do get separated and include them in all your kit packing plans for food, water, treats, and a familiar toy to help keep them as calm as possible.

- Hollie

You can learn more on how to help you and your pets be better prepared by visiting mil.wa.gov/personal and watch our video on pet preparedness on our EMDPrepare YouTube page, too!

-Danté, Washington Emergency Management Division

I remember the Oct. 17 Loma Prieta earthquake very clearly. I remember the fires in the Marina District of SF, the bay bridge collapse, the Cypress freeway pancaking, and I remember walking around SF seeing brick buildings just gutted and fallen apart.

How much general progress has the west coast made in terms of earthquake retrofitting in the past ~30ish years or so? If/when we get another ~7ish earthquake in a major metro area, can we feel relatively safe that our day-to-day life won't be interrupted for more than a day or so?

Since 1989 Caltrans has funded a bridge retrofit program throughout the state. The issues related to buildings that were damaged in the Marina District relate to "soft story" due to garage door openings at grade. Upgrades on these buildings are in progress, and SF has a mandatory retrofit ordinance for these types of buildings. So, work is in progress. For information on societal impacts from a regional earthquake in the Bay Area, see the link below for a Hayward fault scenario project: https://pubs.er.usgs.gov/publication/sir20175013

- Mark

flip

As Mark said, there has been progress on fortifying infrastructure and certain vulnerable building types. Unreinforced masonry (red brick) buildings have gone through a mandatory retrofit ordinance so many of those buildings have been improved. The vulnerable apartment buildings with a weak first story like those in the Marina District have also been included in voluntary and mandatory retrofit ordinances in many cities. Some additional info and resources here for soft-story retrofits. Older hospital buildings, schools, under reinforced concrete frame buildings are in the plans as well. Ever since Hurricane Katrina devastated New Orleans and surrounding areas and much of the population was displaced and never returned, cities and jurisdictions are looking at ways to make the community more resilient so after a natural disaster, the community can shelter in place and recover more quickly.

~ Emory (Simpson Strong-Tie)

It seems pretty obvious that Seattle is woefully unprepared.

1 - Water and plumbing need 50+ years to be prepared for an earthquake. 2 months to get plumbing back is shameful and it’s absurd we aren’t giving SPU the funding they need now.

https://www.seattletimes.com/seattle-news/times-watchdog/seattle-would-lose-all-water-pressure-within-24-hours-of-catastrophic-earthquake-city-study-says/

2 - Almost all of the videos I’ve seen King County and Washington State put out on this subject assumes that people live in houses. Are we just saying “good luck” to everyone who lives in condos and apartments? Where are they supposed to bury their garbage and excrement? How are they supposed to store supplies when they live in studios and small spaces?

3 - I’ve seen the maps of the fault lines (especially for the Seattle quake) and many times these run through residential neighborhoods. Are we assuming most of the people who live along these fault lines are going to be in serious trouble and if so, why is there not more awareness on the subject?

4 - What’s the point of building out all these light rails and bridges if we know they’re likely going to be destroyed by next big quake? I’ve never heard of any retrofitting projects to make them safe. Really feels like we’re just shrugging our shoulders on that one.

Overall, what I’ve learned from all the research on this subject is that if you don’t live in a house in a neighborhood that isn’t directly on a fault line, you will be in a world of hurt when the earthquake finally happens. Is this accurate? So the best thing people can do is just move if they don’t have a house in one of the lucky neighborhoods?

Hi Fancy_Situation - good questions, and we can appreciate your concerns - a LOT more needs to be done to prepare for these hazards.

I'll take a crack at part 4 of your question to start:
Any time we build new things - bridges, infrastructure, etc., is a chance to build in a way that better reflects the hazards we understand. For new bridges, light rail, etc., new construction is designed with seismic hazard appropriate for the area in mind, so new bridges are designed to survive earthquakes.

As far as retrofitting or work - a memorable change could be getting rid of the Alaskan Way Viaduct a few years ago - it was understood that that bridge would not stand up to seismic forces, so it was removed. Besides that, Washington DOT has been aware of, and working on seismically retrofitting bridges in Washington for over a decade now - you can see what they've been working on on their site. Still a lot of work to do, but they have already done a lot of work.
https://wsdot.wa.gov/construction-planning/preserving-our-roads-bridges/bridge-structure-preservation

-Brian

And I will take a crack at part of part 2 of your question. Living in small studios or apartments absolutely causes us to be creative in how we store supplies. It might not be possible to store 2 weeks worth of water - 1 gallon, per person (and pets) per day - but it might be possible to store three days worth and/or keep a purifying straw in your kit, assuming there is access to alternate water sources. You might not be able to have tons of extra cans, but you could get dehydrated meals or meals ready to eat. When preparing for a disaster, make it as individualized as possible which includes planning for the space you live in and what are the most immediate needs for you and your family. Doing something is always better than doing nothing on your preparedness journey.

-Hollie

Are there any anticipated advancements in modeling or warning technology? I feel like I never hear about updates on the systems that are used (or much about the systems at all, really).

Researchers and major agencies like NOAA are always working on advancements in modeling and warning technology. Here in Washington we are pushing for vital upgrades to the National Tsunami Warning Center's systems that will allow better tsunami forecasting and alerting capabilities across the board, but especially for our state. Likewise, many people are working on other methods for tracking the creation of tsunamis, as right now we have to rely on tide gauges and DART buoys which delays our response time by quite a bit.

If you're in Washington, I suggest following https://twitter.com/waEMD as we often talk about any updates and new mapping/modeling.

- Elyssa

I've been told that the Olympic Peninsula should be prepared for 1 month+ of no outside contact if the Cascadia fault lets loose. Last year, Forks WA was fully isolated for several days due to multiple landslides on 101 and 112. Even the forest service roads were out. A friend ended up trapped out there and needed to hike out along the ODT after a few days when their meds ran out.

Should people on the Olympic Peninsula be more prepared than other regions?

It's true that while we tell everyone to be "2 Weeks Ready", when we're in rural communities like the outer coast, Olympic Peninsula, etc, we do suggest being at least 1 month ready. There is a very good chance some of those communities will be cut off even longer due to infrastructure damage (think of how many bridges you have to cross just to get into Aberdeen!). We want everyone to be as prepared as possible - but it's important to understand the specific situations your area will face.

Here's a good site for anyone who needs some help starting their preparedness journey: https://mil.wa.gov/preparedness

- Elyssa

Aside from implementing this early warning system, what are WA / OR actively doing to prepare for this earthquake?

What is something they could do that would most significantly mitigate the after effects?

On the tsunami side here in Washington we're publishing evacuation maps, building vertical evacuation structures, working with ports and marinas to mitigate their risk, and conducting TONS of outreach and education across the state. We work very closely with the local Tribes, counties, cities, and other organizations to get information out and fill gaps. We also create lots of cool resources and are always working to increase our social media presence.

The most significant mitigation efforts are improving our infrastructure. Ensuring our roads, bridges, buildings, and utilities are functional after the shaking is imperative to responding in time to save lives.

- Elyssa

I live in Ocean Shores WA. There is one road in/out of town and a population of 6k or so. In the event of a Tsunami, it seems unreasonable that many people will have the time to drive out.

The copalis ghost forest is right down the road from here and tree stumps still stand from the 1700 Tsunami. Does it make sense to build a tree fort as a way to survive?

In lieu of having an evacuation structure or viable evacuation path to high ground available to you the next best course of action is to move as far inland or bayside in this case and then upwards as possible. So for south-central Ocean Shores it would be best to head towards Duck Lake and then get as high as you can via a multi-story building or other elevated structure.

Every foot you can travel away from the coast and upwards greatly improves your chances of survival.

-Daniel

I suggest you get yourself a helium tank, a bunch of balloons, lots of string, a lawn chair, and a BB gun.

I was actually being serious. I know a tree fort sounds silly but trees are still standing from the last big one from over 300 years ago so it stands to reason it could provide shelter from a Tsunami.

I worry about effects similar to lahar flow. It seems just as likely to me that the trees would be useless or a bigger threat than most else.

The trees were also alive and most likely quite healthy when the 1700 tsunami hit them - by now they're standing but they've been dead for hundreds of years, so may not withstand the same forces they did in their prime.

- Elyssa

I'll be in your city in a couple weeks for some fall vacation time. Way down near Damon Point. I think about the impossibility of getting out of there in a tsunami each year.

Cool! I am a 10 minute walk from Damon points. Funny story, they do a test of the warning system every month. They also do test once a year that sounds different from the monthly test. I wasn't aware of this when I moved here. So a month after moving in the yearly warning goes off and I grabbed the cat and jumped in the car and took off. Shortly after freaking the F out I realized it was just another test.

Oh no, I'm sorry we missed you with our test messaging! We test the sirens with the actual wailing sound on the Great Washington ShakeOut (so tomorrow, 10/20). We do a big ad campaign ahead of the test but it always misses a few folks. I'm glad you jumped into action and took your kitty with you though! (Picture....?)

- Elyssa

I live a couple hundred feet from one of the Seattle fault lines to the west. How active is that fault and is another quake likely soon ?

Hello, the last major earthquake on the Seattle fault happened about 1,100 years ago. the geologic record shows about 5 additional earthquakes in the past 3,500 years. All around magnitude 6.5-7 range. The Seattle fault is an active fault, meaning it could have an earthquake today, a year from now, or 1,000 years from now. A large earthquake on this fault could cause a large tsunami: https://fortress.wa.gov/dnr/geologydata/tsunami\_hazard\_maps/ger\_ms2022-03\_tsunami\_hazard\_seattle\_fault.zip

-Corina, Washington Geological Survey

How predictable are the areas of most damage? Would a home buyer benefit by looking at any maps in a particular area, or could the worst happen anywhere?

Earthquake damage to buildings is related to shaking intensity, building construction, and site soils. Building age can be an indicator of potential damage (since building codes for new buildings have changed in the last 50 years). Looking at local soil maps (soil liquefaction hazard) is useful in understanding the potential for damage. For Washington State see DNR site for geologic hazard maps: https://www.dnr.wa.gov/programs-and-services/geology/geologic-hazards/geologic-hazard-maps

- Mark

Close proximity to an active fault line generally indicates higher shaking intensity. Here's some information for Washington State. However damage can vary depending on the age of the home and vulnerabilities that might exist. In a high intensity shaking area you can have one home with minor damage and the one next door has slid off its foundation. So when looking to buy a home you'll want to know about the local hazards, but also know the age of the home and if it has been retrofitted.

~ Emory (Simpson Strong-Tie)

I live in a 1960s building in Vancouver BC, have we chosen the worst place to live?

Well I live in a 1970s home in the San Francisco Bay Area. To me it is one of the best places to live despite the earthquake risks. Those earthquakes are responsible for the wonderful hills that I love for mountain biking and snowboarding. If you have a plan on what to do when an earthquake hits, you look at the risk of your structure/home and decide on retrofit and insurance options, you'll be able to worry less and enjoy the area you live. Here's some information on retrofit options.

~ Emory (Simpson Strong-Tie)

For more information on geologic hazards in Vancouver BC, see this link: https://www.cgenarchive.org/vancouver.html

Hope this helps - Mark

Is one of you responsible for this absolutely amazing parody of Smash Mouth’s Allstar turned into an earthquake parody?

Yes! That is our incredible earthquake, volcano, and musical parody expert, Brian Yankovich. We love having him on our team and hope the song blows up the interwebs.

-Hollie

I prefer "Weird Brian," but thanks for the benefit of the doubt!

-Brian

Are there any known methods that can accurately predict an earthquake before they happen that are simply not feasible to implement or are there just no known methods to give significant advance warning?

ShakeAlert is an active earthquake early warning system active on the west coast of the US. Managed by the USGS with University and State partners, ShakeAlert can produce warnings that shaking will arrive soon. To learn more check out ShakeAlert.org.

ShakeAlert can provide seconds, perhaps minutes of warning for great earthquakes but if by"significant advanced warning " you mean hours, days, or weeks the answer is no. Earthquake prediction is not possible. We can however predict how strong the ground is likely to shake in 50, 100, or 2500 years in a given area that can lead to appropriate building codes to better protect buildings.

When I was at UC Berkely in the early 2000's I had a professor in an intro engineering class tell us that hiding under desks during an earthquake is a terrible idea, and that it's actually better to hide next to walls. It was extremely convincing, but in the time sense I feel like I am still hearing and seeing recommendations to hide under desks.

Do you know the correct/formal recommendation from whatever earthquake association there is?

Hi GroupFunInBed - thanks for the question!
The official recommendation for buildings with U.S. codes is to "Drop, Cover, and Hold On." This means:
1) Lower your center of gravity by getting low to the ground
2) Cover your head and neck, and take cover if possible
3) Hold on to your cover, and stay there until the Shaking stops.
Being under a sturdy desk or table is better than just being next to something, because it protects you from falling debris from above, and provides a bit of extra cover from things falling from the sides as well.
However, if there's not a sturdy desk or table nearby (like, if the only table nearby is a glass coffee table ...not ideal), getting next to an interior wall is better than being just out in the open.
But again - That interior wall is not a safe place to be if you're under an unsecured picture frame, or if it's under a cabinet that can open up and drop a bunch of dishes on you.

So, for what to do in a variety of situations, here's a video we put together based on the current recommendations from structural engineers and earthquake experts: https://www.youtube.com/watch?v=NHm6ZYfq8Pk

Part of the reason we recommend doing the ShakeOut Drill is taking just that little bit of time to think about whether those places that you spend the most time (your home, your office, your school, your bed, etc.), and take some time to fix those things.
So for a guide on some of the things you can do now, to help make your home a safer place when the ground shakes, I recommend checking out earthquake country alliance's site on how to Secure your space: https://www.earthquakecountry.org/Step1

Hope this helps! -Brian

Thanks. Im surprised to hear that because the professor that taught me was, IIRC, a fairly prominent person in the world of earthquake research & safety, at least at the time. I recall him showing a video or something of the sort that was explicitly stating NOT to go under desks because it causes people to get crush, regardless of how sturdy it was (the sturdiest of desks is not going to hold up a roof falling through.

I may be misremembering some part of it, but thanks for clarifying - given the sources you cited it seems that must be the case!

If you can't tell from some of our other answers, there are some very... strongly opinionated camps... when it comes to what's best to do during ground shaking. ;) But that's why we share sources!

- Elyssa

I saw a recent headline saying the height of the CSZ tsunami may actually be 200' vs 100'. Is that true? If so, what does this do to the marked safe zones? Push them 100' higher?

I live about 4 miles from the coast on a river and my house is about 2' above the tsunami zone on the map. It's also built on a concrete pad on top of sand. And on stilts. It's screwed, right?

Hello, our recent tsunami modeling shows that some places on the outer coast of Washington may see tsunami inundation (flooding) over 100' locally, but it depends on the local topography and geography on how deep the inundation is. on our geologic information portal we show where we have tsunami hazards mapped and where high ground is located as well as mapped evacuation routes: https://geologyportal.dnr.wa.gov/2d-view#wigm?-13969862,-12969455,5570342,6477802?Surface_Geology,500k_Surface_Geology,Map_Units

https://www.dnr.wa.gov/programs-and-services/geology/geologic-hazards/Tsunamis

Corina, Washington Geological Survey

I just moved to Oregon from Hawaii... some of the bridges around here look a little rough. Are the old bridges at major crossing like the Columbia going to withstand a major earthquake, and is all new infrastructure supposed to withstand a certain strength of earthquake?

NotFrancis- Welcome to beautiful Oregon! The Portland area alone has dozens of bridges and the coastal region as well. These bridges run the gambit from pretty new competent structures to very old bridges built before seismic codes were in place. Clearly many bridges will fail in a Cascadia M9 earthquake but due in part to the variety of structures, the natural period of vibration for them, and their orientation, some if not many will survive. The coastal area will get very strong shaking and Oregon DOT recently produced a report on the vulnerability of those structures. https://www.oregon.gov/odot/Bridge/Documents/2021BCR.pdf Bill Steele

How can I fortify my house for earthquakes?

Depending on the age and building style of your home there are many retrofit options. Residential buildings with raised floor construction (a crawl space or basement) generally built before 1985 have some unique vulnerabilities. The most bang for your retrofit buck is generally strengthening the attachment of the home to the foundation and reinforcing the cripple wall area in the crawlspace. This retrofit guide will give you an overview. Another good thing to do is look around your home and secure things that could fall and injure you in an earthquake. Anchor book cases and other furniture to the walls. Make sure your water heater is strapped to the wall. I also use some putty stuff called museum wax to secure heavy things on shelves that may fall. There's more information for homeowners here along with a video of an owner who retrofitted her home/business and how it fared in an earthquake in Napa in 2014.

~ Emory (Simpson Strong-Tie)

I live in a liquefaction zone in the Seattle area (near Alki beach) and am confused on the implications of what this means. Is it likely that older homes and buildings completely collapse due to the soil shifting? Is the risk that they tilt off of the foundations? The way I hear people refer to liquefaction zones in common conversation is almost that they expect them to become underwater, but I don't think that's correct?

Hello, liquefaction can happen during earthquake shaking and it can take many forms, from ground cracking, to small sand eruptions, to acting like quicksand where buildings and infrastructure can submerge. it depends on the earthquake and the soil and there is no way to know for sure exactly how the soil will react. newer homes and critical infrastructure are usually designed to withstand earthquake shaking and likely also the liquefaction. older homes may not fare as well.

-Corina, Washington Geological Survey

Growing up, I have always been told that the "big one" is coming. There seems to be new odds of this occurring published every year, are there any recent developments in the probability of this occuring? Along the same vein, I have always read that earthquake prediction is near impossible - is this something that you see changing in the future? What do you think is the biggest/most prevalent misconception about earthquakes and tsunamis?

I always take issue with "the" big one and prefer to use "a" big one because big is relative to how close you are to the earthquake. For here, Seattle at PNSN HQ at UW, there are generally 3 types of events that can have strong shaking:-deep (like 40 miles) intraslab events like the 2001 M6.8 Nisqually earthquake near Olympia. Previous similar events happened in 1965 and 1949.-shallow crustal earthquakes, for example, like the Seattle Fault earthquake (M7ish) around 1100 years ago-offshore subduction zone events than can be up to M9, the last of which happened on January 26, 1700. The odds for this type event is of order 15% in the next 50 years.The USGS typically updates their hazard maps on multiyear cycles that take into account new data like paleoseismic data from trenching faults or drilling cores offshore. Overall there have not been significant changes lately. A small change in the last few years is the recognition that the Seattle basin and other similar deep basins can amplify shaking a bit more than previously expected. These amplifications from basins (think: gently shaking a plate and watching a tower of jello shake much stronger than the plate) are most prominent at longer periods, like 3s, that will only impact tall buildings with long resonant periods. A rough rule of thumb for this is 1s period for every 10 stories so 3s for 30 story building. Building codes can get updated following hazard map updates, but I believe those happen less frequently and lag the hazard map changes which lag the science by a few years in order for the various stakeholders to adjust their portion of the sausage making process.
Also, there is no reproducible scientific evidence that prediction will ever be possible.

-Alex (seismologist at the Pacific Northwest Seismic Network)

Is there modeling that shows Tsunami risk / height / distance inland for Pudget Sound?

If there are different size and location ruptures along the Juan de Fuca plate, do they show what the potential impact is to Seattle?

There sure is! We have mapping for the entire Washington coast for a Cascadia Subduction Zone 9.0 quake and tsunami, which you can find here:

https://mil.wa.gov/tsunami-resources

Our modeling doesn't show different Cascadia scenarios; we use the 9.0 scenario because it's a 2500-year event and we consider it our largest considered event for planning purposes. At this website you can also find mapping for a Seattle Fault scenario, however!

- Elyssa

You can find all of our tsunami modeling results available at https://www.dnr.wa.gov/programs-and-services/geology/geologic-hazards/tsunamis#tsunami-hazard-maps. This includes both CSZ and Seattle Fault inundation model results for Puget Sound and Tacoma Fault for the Tacoma area specifically.

-Daniel (WGS)

Would you recommend a home buyer who intends to hold their home for 20 years (that's more than double the average time a home is owned in the US) avoid the coast of the pacific north west, full stop, or would you recommend only buying homes that are retrofit to california-like standards, or is the risk reasonably low and you'd recommend buying a home in the NW without any retrofit and with no immediate plans to do any?

We DEFINITELY want you to retrofit or build to the best possible standards if you're in an earthquake-prone area. It's up to you whether you feel like the coast is too big a risk as a homeowner - every place on earth has hazards, and each have their own pros and cons, so it's not like you can avoid risk completely. I say live where you want to live and be smart about how you mitigate and prepare for the hazards in that area. In the end, the Pacific Northwest is a beautiful, amazing place to live, and I personally wouldn't trade that for anything. Even avoiding the Big One.

- Elyssa

Just like some of the questions about earthquake insurance, those kinds of questions and decisions are personal and related to your risk tolerance and the things you do to protect your investment. I've chosen to buy an older 1970 home in the San Francisco East Bay area. The Hayward fault is near by and has a pretty high probability of a big earthquake. I've been in my home close to 20 years and love it here. Strengthening the connection of the home to the foundation is a no brainer for me. I'm considering earthquake insurance but haven't pulled the trigger yet. Everyone's situation is different.

~ Emory (Simpson Strong-Tie)

I have a question inspired by recent flooding in Florida: is there any difference in how long floodwaters remain in a low area, arising from the way they were deposited? Does the tsunami wave ultimately recede faster due to the same wave behaviour that brings it in, where floodwaters deposited by rain might stay high longer?

Unlike storm surge that is driven by wind power, tsunamis are driven by the force of gravity. Meaning that while their is some similarity in how they flood, they also have some significant differences as well. As far as residence time of water in an inundated area, the answer is highly variable depending primarily on local topography as it is the force of gravity that pushes it back out to sea, as well as the presence of barrier features preventing it from flowing back out (e.g road grades).

In some cases such as in steep topography, flowback will be immediate following inundation. In others it could take days to weeks before the water completely drains out. For example, some areas in Japan were still experiencing flooding 3 weeks after the Tohoku event.

This could potentially lead to significant concern of saltwater contamination of water systems and farmland following the event.

-Daniel (WGS)

Japan has tsunami memory stones telling folks not to build in an area. Did Indian Tribes do anything similar on the West Coast?

While the Tribes here didn't use memory stones like in Japan, tsunamis and earthquakes do feature prominently in many of their stories. I especially love this Atlas Obscura article that includes a discussion about the battles of Thunderbird and Whale, and how this mythology shaped the knowledge of the coastal tribes. Plus, the art in it is BEAUTIFUL.

https://www.atlasobscura.com/articles/pacific-northwest-prepares-for-massive-earthquake

- Elyssa

how much would a tsunami effectively mess up king county? since we have the westerly protection via the islands in the sound and the west spit of washington

All 3,000 miles of Washington state's coastline can be impacted by tsunamis, that includes our inner coast waterways. The amount of inundation (water depth over land) expected from a tsunami depends on its origin. If it is a local tsunami, wave arrival is typically less than 3 hours and in some parts of the state, this can be as little as a couple minutes as with the Seattle Fault in King County. This can have a significant impact on our coastline infrastructure, in particular our maritime community.

The most important take away is whether you feel shaking or get an alert, you want to first drop, cover, and hold on and head to high ground immediately. You can learn more about how to sign up for tsunami alerts and earthquake early warning on mil.wa.gov/alerts . You can also learn more about tsunami risk at mil.wa.gov/tsunamis.

Danté, Washington Emergency Management Division

Being located within the Puget Sound does not provide much protection from local tsunamis such as the Cascadia Subduction Zone or some local crustal faults such as the Seattle fault. You can find our hazard data at https://www.dnr.wa.gov/programs-and-services/geology/geologic-hazards/tsunamis#tsunami-hazard-maps and visually see it on at https://geologyportal.dnr.wa.gov/.

For distant events outside the PNW or local crustal faults farther away such as up in the Frasier River delta the impacts to King County would expected to be minor and likely only of concern to maritime interests.

-Daniel (WGS)

As a tourist to the PNW, I was interested by all of the tsunami evacuation signs I saw. Many of them had arrows pointing to where to go.

I've always wondered: how likely are those signs to be helpful to someone like me, who is new to the area? Would we reasonably have time to get to that higher ground?

Great question! Here at WA Emergency Management Division we are actually in the process of analyzing our mapped evacuation routes to determine where additional signage is needed to ensure the routes are obvious to anyone, visitors included, and people on foot who may not have great visibility. We'll then be helping local jurisdictions purchase and install more signs based on the data collected. If you see UW students walking tsunami evacuation routes with clip boards, pointing in random directions and taking pictures, that's likely our team! (Gosh, I hope it is...)

Regarding high ground, your time depends on the event and your location. However, highly visible and easy to understand signage will save precious time, and that's why we're dedicated to getting those routes covered.

- Elyssa

How far east can the Everett tsunami siren be heard?

How far east can a large tsunami travel up the Skagit and Snohomish valleys?

The tsunami sirens can be heard about 500 feet in any direction, but this definitely depends on the weather - nice sunny days with a good wind can carry the sound farther, rain dampens it, etc. Anything between you and the siren, such as buildings or hills, also impact your ability to hear the sirens.

- Elyssa

You can find the modeled inundation extent on our Geologic Information Portal at https://geologyportal.dnr.wa.gov/ for details. For the Skagit valley near Bow-Edison inland travel is roughly 3 miles and 2.5 miles from the Swinomish Channel. The Snohomish valley has modeled inundation travelling up to 20 miles up the river channel almost to the town of Snohomish, however this is entirely contained within the estuarian areas and river channel farther upriver.

-Daniel (WGS)

Obviously an earthquake could happen out of nowhere * but * are there any early warning signs that non-experts could watch out for?

Thanks

While we wish there were a telltale sign that an earthquake is coming there is no magic ball (or dog kennel) that can predict earthquakes. Earthquake swarms can be a sign that a fault is moving and they may be foreshocks to a bigger event. The best tool we have now is ShakeAlert/earthquake early warning, which may give a few seconds to minutes of warning before an earthquake happens: https://www.shakealert.org/
get the myshake app on your local app store to sign up for these alerts. https://myshake.berkeley.edu/
-Corina, Washington Geological Survey

Tsunami vertical evacuation towers are still few and far between along the PNW coast. Are there any state or federal funding opportunities (thinking of recent infrastructure bills) that local communities can access to help speed up construction of these towers? I know FEMA has the ability to cover a large portion of the costs, but that still leaves potentially millions of dollars for cities or counties to need to cover.

Great question! Our newest tower was the first FEMA-funded tower in the US using the BRIC program (link below). WA EMD helps local jurisdictions apply for funding every year for all sorts of projects through this program, including vertical evacuation structures. Several projects are at various stages in the process right now, including ones for Ocean Shores and Westport. FEMA usually matches 75% of the total project budget, meaning the jurisdiction still has to pony up 25% - which in the case of these structures is still millions of dollars, as you said. The state is exploring other ways to assist with this local match, and I hope we have some good news for you with the next BRIC round!

https://www.fema.gov/grants/mitigation/building-resilient-infrastructure-communities

- Elyssa

Considering a full Cascadia rupture could be a massive national disaster, how do you communicate to the country, not just the PNW, about the risk?

It can be challenging, but journalists are interested and help get the word out. Famous national articles like: https://www.newyorker.com/magazine/2015/07/20/the-really-big-one help, and also this recent New York times piece: https://www.nytimes.com/2022/02/07/us/tsunami-northwest-evacuation-towers.html

Also, forums like this, and education in schools and universities helps.

-Corina, Washington Geological Survey

I like this question. There are multiple ways we communicate the risks with all levels of government both in the PNW and outside of it.

One of the ways is through exercises like Cascadia Rising which is a functional exercise done across multiple days that involves all levels of government, multiple states, and private partners. You can read about the 2022 event here: https://mil.wa.gov/cascadia-rising

We also have myriad ways to share response capabilities, including through the Emergency Management Assistance Compact as well as the Stafford Act which allows local and state jurisdictions to access federal funds and personnel through the Federal Emergency Management Agency in the event of a disaster or emergency declaration.

-Hollie

Is it true new earthquake faults are discovered all the time? Why is that?

As geologists continue to map the rocks and faults they can discover new faults. Additionally, as new data are collected they help to better refine, or discover new faults that can cause earthquakes. New technologies like Lidar and better remote sensing, geophysical, and seismic imaging techniques are also crucial for fault discovery.

-Corina, Washington Geological Survey

Just to add to that - why don't we know about all the faults?
It's pretty hard to find things that are several miles below the ground that only do things to make you notice that they're there once every few hundred years.
...usually knowing that there's a reason to look there (because of small earthquakes) is the reason geologists/seismologists begin looking in the first place.

But like Corina said - better technology will help notice more of these even when they aren't being specifically looked for!
-Brian

What should you do when you are warned about a tsunami?

Excellent question! Whether you receive an official alert for a tsunami OR if you see or feel natural warning signs of a tsunami (feel ground shaking, see water receding, see the water acting abnormally, etc.) you want to first drop, cover, and hold on (if you feel shaking) and then head to high ground immediately.

You can also learn how to receive alerts of all kinds, including tsunamis at mil.wa.gov/alerts. If you want to learn about the different tsunami alert levels and what they mean, visit mil.wa.gov/tsunami

-Danté, Washington Emergency Managment Division

I live in the San Juan Islands, what risk do we islanders have to tsunamis? Does the Strait of Juan de Fuca increase or decrease the wave height?

Hi, great question, our models from a Cascadia subduction zone earthquake induced tsunami show that there will be some inundation along the beaches and shorelines of the San Juan Islands and in east sound and Friday harbor. You can check out the modeled tsunami inundation on Washington Geological Survey's geologic information portal: https://geologyportal.dnr.wa.gov/2d-view#wigm?0,0,0,0

you can see a simulation video of it here: https://youtu.be/fLIvp3bCDEU

-Corina from the Washington Geological Survey

If tactical nukes go off in Ukraine can you detect them ?

Seismology is one of the traditional fields involved in detection of underground nuclear testing since they can be as large as M6 earthquakes. The PNW is around 80 degrees away from Ukraine. We don't monitor outside of our region, but we still detect earthquakes from around the world. At 80 degrees, we can probably detect M4.5 earthquakes.... does that mean we can detect a nuke? If that nuke was buried underground and big enough, yes we'd likely see it. If a nuke were to explode at the surface where a lot of the energy leaks into the atmosphere and doesn't couple into the ground, then we'd likely not be able to see it if it's similar in size or smaller to the reported underground nuclear tests in the DPRK which, for reference, had seismic magnitudes in the rough neighborhood of M5.0. Infrasound acoustic arrays are also another common tool used to detect nuclear tests. There are infrasound stations in the PNW around some of our volcanoes, but they are not configured like the various IMS (International Monitoring System) infrasound arrays are for nuke detection. https://www.ctbto.org/our-work/ims-map
-Alex, PNSN

When will I as a central Californian have oceanfront property?

Due to natural disasters and global changes? Probably not in your lifetime. Instead of waiting, you could move closer to the coast, or just go visit often.

~ Emory (Simpson Strong-Tie)

Can we get our yearly update on "the big one"?

Greetings ObamaBin-

It is now 321 years since the January 26th 1700 M9 Cascadia Subduction Zone Earthquake. The probability of reoccurrence is still best estimated to be 14% in 50 years. Research using 3d earth models of the region and a lot of super computer time produced ~50 different scenarios for the next Cascadia Earthquake. The results show a lot of variation on shaking levels depending on where the earthquake initiates. The deep sedimentary basins most of our Puget Sound Region cities are built on will strongly amplify longer period waves from this quake that will increase loads on tall buildings and structures.

I live across the street from the beach in Oregon. Is it necessary to get inland before a tsunami, or would I be safe on the cliffs that have a large (50+ foot) drop to the water?

For Oregon, you can check out if you are in the tsunami zone and what evacuation products are available to you at http://nvs.nanoos.org/TsunamiEvac. Generally at 50+ feet elevation you would probably be considered on high ground already, however tsunami behavior is highly location specific so it is good to verify!

-Daniel (WGS)

My house is in an area where liquifaction is shown as high risk. It's along an Oregon river on the edge of the food plain. Can anything be done on a budget to reduce the chance of major structural damage or sinking into the earth during an earthquake?

You can consult with a geotechnical engineer and they can tell you if there are mitigation strategies to retrofit your home for liquefaction. Unfortunately, after a building is constructed it is much harder to mitigate for this hazard.

-Corina, Washington Geological Survey

Is the New Madrid fault line of concern? Is it overdue? Should more midwesterners be informed of it, especially since few of the structures seem earthquake resistant (to me)?

The New Madrid Faults produced a series of Magnitude 7 + earthquakes in the Winter of 1811-1812 that rang church bells in Boston. Why these earthquakes occurred where they did and how rapidly (os slowly) strain is accumulating there is still a topic of scientific debate. People in the Central US from Memphis north into Illinois should be prepared for strong shaking with the understanding these earthquakes are rare but when they occur they shake hard and effect a very large region. The 1811-1812 sequence produced large areas of liquefaction of the soil column that would likely add greatly to the damage. Bill Steele- PNSN

Those of us in the Puget sound are under the assumption that if the big one would hit it would wake up all of the sleeping giants like Mt pilchuck, Baker, Helens, Rainier and etc. How likely if at all is that possibility?

Volcanic eruptions often are accompanied by many (small) earthquakes. A large nearby earthquake might push a volcano that was already about to erupt over the edge, but generally no- big earthquakes don't 'wake up' volcanoes.

-Alex

How come I've been told California is due for a huge devastating earthquake ever since I was a kid but I'm an adult now and we're still just crossing along with mostly minor stuff?

There will be devastating earthquakes in California, and much of the PNW in the future. We don't know when exactly, "soon" in geologic time could mean today or 500 years from now.

-Corina