We're earthquake and tsunami experts from Washington, California & Oregon. Ask us Anything!

What's the deal with " the big one" that's supposed to hit of the coast of WA?

The Cascadia subduction zone, when runs along the coasts of Vancouver Island, Washington, Oregon, and northern California, has been observed geologically to have magnitude 8-9 earthquakes about every few hundred years. So it would not be surprising (~25% chance) if there were another in the next 50 years. - John

That's it? "The big one" isn't going to destroy humanity along the west coast? I can sleep sound?

What we want you to do is get at least 2 Weeks Ready because help is unlikely to arrive for several days (maybe weeks). We have tips at mil.wa.gov/preparedness -- Steven

Since you can't tell where this fault line will go exactly, what happens if it's out off the coast and causes a tsunami? About how much warning time could there be?

You can actually use this simulation to answer your question. It came out a few months ago. https://youtu.be/e5PJQW_6k6M

There have been quite a few M9s around the world in even less prepared places, and none have destroyed humanity. Some tsunamis have locally erased it for a time for a strip along the coast, however.

What's the current consensus on the Cascadia subduction zone going off in our lifetime?

For the southern half of Cascadia, M8-9 events have happened about once every 250 years, with the last one being in 1700. The chances in the 50 years is about 30-40%. For the northern half of Cascadia, roughly mid-Oregon north, we’ve seen M9 events about every 450 years, also with the last being in 1700. For the next 50 years, the chances of another are about 10-20%. - John

How would a major earthquake on the southern half of Cascadia subduction zone impact the northern half?

Will a major earthquake on the southern half increase the chances of a major earthquake on the northern half? Or will it decrease the chances by relieving pressure?

The shaking would extend north (and south) for 50 to 100 km fairly strongly, and tsunami waves along the coast can extend beyond the immediate zone of rupture. But Puget Sound would see only minor impacts.

If you had unlimited funding and no red tape, what areas would you spend it on that is being under funded or over looked?

Thank you for asking this question. I love it when people hand me the magic wand. J There are two main areas when it comes to preparing for these large events: People and Things. The things are the built environment, the infrastructure, and the homes we live in.

Since I have this handy magic wand, I will start with infrastructure as this is the vital services we all rely on to live our modern lives. The fragility of our infrastructure can be seen in what is happening in California now with the black outs. This would mean updating and modernizing power, water, sewer, telecommunications, transportation/bridges, and the other lifelines we rely on.

The second thing I would do is to make sure all homes, whether is a single family residence or apartment buildings are retrofitted to withstand the shaking and to be immediately usable. This would mean that you would not have to go to a shelter if your building was damaged.

The third thing I would do is to ensure that all residents and visitors on our coasts are able to get to high ground quickly. This could mean hardening the evacuation routes or building vertical evacuation structures for those who don’t have high ground to get to, or aren’t physically capable of evacuating.

The fourth wave of my wand would educate people on how to prepare for these types of disaster. We know it will take time for help to arrive so you will be your own, and your family’s first responders. Take some time to learn more about how to be at least self-sufficient for at least two weeks. -Althea

What are the safety measures that us, civilians, should take in case of a tsunami? What should we do to increase our survival chances untill the rescue arrives?

If a lesson can be learnt from March 11th in Japan: find out today where you should evacuate and plan your route. You probably will have about 15 minutes. Coastal cities in Japan (even Tokyo) have signs at different locations showing how many meters above sea level you are. Surviving a tsunami is about surviving the short time when the wave hits.

Completely agree, learn your routes now and practice evacuatiing ahead of time. Here is a link to Washington's evacuation maps: https://www.dnr.wa.gov/programs-and-services/geology/geologic-hazards/tsunamis/#preparation-and-evacuation.6

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Corina, WGS

This is a great question. Tsunamis can be caused by earthquakes under the ocean. If you live near a coast, or visit the ocean, you could be at risk when a tsunami happens.

The first thing to do BEFORE YOU GO TO THE BEACH is know if you are in the bad zone or not. There are tsunami evacuation maps that show where you need to evacuate. Many states and territories provide these online. I'll post links below.

Tsunamis can come from local sources (Cascadia) or distant sources (Japan, Chile). For a local source, you will most likely feel the shaking from the very large earthquake. The first waves could arrives within 15 minutes if you are on the open ocean. When you feel the shaking, Drop, cover and Hold on, and then get to high ground on foot as soon as possible. Don’t try to drive unless you have a functional need. Stay on high ground as the waves could continue to come in for many hours. There will likely be no official warning issued as there just isn’t time.

If it is a distant source, you will likely get a warning through NOAA’s tsunami warning system. A distant source means that it will take hours to arrive and you will not be affected by the earthquake. Stay away from the beaches and harbors.

You can find out more by going to the websites below.

Washington: https://www.dnr.wa.gov/programs-and-services/geology/geologic-hazards/emergency-preparedness#tsunamis.10

Oregon: https://www.oregongeology.org/tsuclearinghouse/faq-tsunami.htm

-Althea

I live in CA, what is the likelihood we will get a warning prior to another "big one" and how long may that warning be? After I get that warning, what the hell should I do?

There is a high probability you will receive a warning an earthquake has occured before the shaking reaches you if you are using an app powered by ShakeAlert. The LA App is available now for folks in LA County and one or more apps will be available for other parts of California soon. What you should do in most cases is Drop, cover , and hold on! Protect yourself from falling objects Where You Are. Many injuries occured when people try to flee to what they perceive as a safer area.

I can tell u this, we deff wont get that warning on our cell phones like we are suppose to, those last 2 big ones we had screwed us and no warning

The system didn't go off because in LA, the max intensity felt was like a 4.0-4.5. They're lowering the threshold now. This will probably result in over-alerting people, but... that's the tradeoff.

A lot of people in LA think they got hit by a 7.1 magnitude earthquake. They didn't - Ridgecrest did. LA felt the <4.5 distant rumblings of the quake over 100 miles away, which certainly was a scary enough experience when you don't know what's going on. Also scary since, I guess normal nearby 4.5 magnitude earthquakes are over quickly, but feeling the similar intensity shaking from a large earthquake from far away can go on for like a minute.

To be clear, the earthquakes did have magnitude 7.1 and 6.4, but the early warning triggers on intensity, which was not high as far away as the city of Los Angeles. - John

For the Ridgecrest M6.4 and 7.1 events, the threshold for warning was set high enough that no warning was issued. The system worked just as designed. The threshold has been lowered so that a repetition of those events would now set off the alarm. It may not be obvious, but the threshold for the early warning alarm is set by shaking intensity. The shaking intensity in LA in those events was not dangerous. People have loudly voiced the opinion that they want warning even if shaking doesn’t reach dangerous levels, which is why the threshold was lowered. - John

The last big ones happened before cell phones existed...

Im talking about the last 2 we had this year, they were back to back

Yeah and only LA County is currently setup for earthquake warnings. The system only goes off if shaking is over 5.0 magnitude. We only felt like a 3.0 - 4.0 magnitude in LA. Hence, no alarm. The USGS and UCLA who run the service said the system was working, there was just no need to warn us. Ridgecrest got nothing because there is no system in place yet.

If it were over 5.0 we would get a warning, don't worry. It would not be very much though. anywhere form 10 seconds to a minute. Enough to possibly save your life, but not as much as we think.

Or none. If the earthquake hits just a few km away, the shaking may beat the warning to you. We're working to make the warnings faster, but it will take a few years to build out the sensors and conquer the data transmission delays.

My 10 year old is super interested in natural disasters.

His question: what is the likelihood of a magnitude 10 earthquake in California?

My question: how can I encourage/support him to pursue his interest in earth sciences as a career?

As a Jedi, your son should be well equipped to feel a disturbance in the force and provide early warning to his classmates :)

I would encourage him by providing as many experiences as possible with STEM related activities including the earth sciences. This could take the shape of field trips to museums, after school or summer programs, visiting places of geologic interest etc. Some of the easiest things would be to make sure he has access to a library and checks out age appropriate books on the subject, watches learning programs on tv, and other things of that nature.

Curiosity is like a fire, if given fuel it will burn.

–Daniel Eungard (Washington Geological Survey)

Just as a note, there's nothing special about 10 on the magnitude scale. It's not a 10/10. Theoretically, you could have a 10.5 or 11.

A 10.0 is simply 10x more intense than a 9.0, which is 10x more intense than an 8.0, and so on. But a 10.0 would be so utterly insane, it's certainly interesting to imagine. A 8.0 would be catastrophic enough. The Great 1906 San Francisco earthquake was a 7.4, for reference.

Only Spinal Tap can "bring it to 11". A M 10 earthquake would require a San Andreas type fault rupturing around the entire planet. We have not found any faults capable of an M 10 but an asteroid strike could rock the world that badly. — Brian

So who’s at the biggest risk??

Risk can be defined many ways. LA has the biggest risk in the sense that it is a large city underlain by many very active faults that run right under towns. - John

How close to the ocean is too close in the event of a tsunami?

I would encourage you to consult local evacuation maps (link for Washington and Oregon below) for coastal areas to find if you are “too close”. More generally, if you are in low lying areas or proximal to the ocean you should immediately move to high ground if you feel strong ground shaking, see abnormal wave behavior, or receive an alert through alert and warning systems.

https://www.dnr.wa.gov/programs-and-services/geology/geologic-hazards/tsunamis#preparation-and-evacuation.6

https://www.oregon.gov/DOGAMI/pages/earthquakes/coastal/tsubrochures.aspx

–Daniel Eungard (Washington Geological Survey)

Based on a quick look at the site (https://www.shakeout.org/howtoparticipate/), it appears as if Turkey and a few other countries where earthquakes are prevalent are not participating.

You mentioned that it's the world's largest earthquake drill, and it sounds like there are many places where some practice could be helpful for the general population.

Any idea why these countries decided not to participate? Thanks!

Good point - There are certainly some areas around the world that would benefit from participating, but don't yet.
That would be a good question for the Southern California Earthquake Center, who run the ShakeOut - but expanding the drill takes time, and a ton of work. The drill was initially only in California, since 2008, and has been expanding ever since - Washington State didn't participate until 2012. — Brian

Have you mentioned the importance in participating in CERT so we can be useful to the community when these things happen?

I found it to be tremendously valuable training.

CERTainly!
Thank you for taking the time to take a Community Emergency Response Team (CERT) training!
Our General Preparedness advice is: Be Informed, Build Kits, Make Plans, and Get Involved - CERT is always one of the recommendations for the 4th part.

For anyone unfamiliar with CERT - this is a community group that trains in first aid/CPR, basic Search and Rescue, and other techniques that would help out in their community after a disaster - not just an earthquake, but large windstorms, snowstorms, etc. After a disaster as large as an earthquake, the people right around you will be the "first" responders, so getting to know your community members is helpful. And if you want to be able to help out as part of a team, CERT is an excellent way to go!

For anyone interested, I recommend checking in to your local Emergency Management office to see what type of CERT opportunities are available.

Thanks for your work! -Brian

So, a few years later, are you guys happy with the famous New Yorker article for bringing attention to the matter? Or did it provoke too much unnecessary fear?

In general, how do you calibrate the level of fear in your messaging?

We actually really like the follow-up article that happened. It's, basically, everything that was cut out of the first one. How to Stay Safe When the Big One Comes. Admittedly, after the article came out, there was a certain quote that talked about everything west of I-5 being destroyed. Well, some people do live west of I-5 so that took that a bit too seriously and we had to calm some nerves. What good it did, though, was encourage people to get prepared. In Washington and Oregon, we encourage residents to be 2 Weeks Ready because we know that it will take many days for help to come after the "big one." Preparing for an earthquake can also help people prepare for winter and snow storms, too. We had a big winter storm in February in the Seattle area, and people with emergency kits were good. People without emergency kits were flooding to the bare shelves of grocery stores hoping to find some bananas or bread. That was a winter storm with warning. Earthquakes give no warning. -- Brian

Is there any for humans to relieve stress on fault lines to prevent city destroying quakes?

No, the stresses are too deep to be easily affected, and the critical points that conceivably could be tweaked to set off earthquakes to relieve stress are unknown. Besides, any earthquake we manage to trigger could turn out to be the dangerous one we are trying to forestall. - John

Hi guys, thank you for doing this AmA! French here, but interested by what could be happening in North America. How high is the risk that the West coast's fault line gets triggered in the following decade/century? What could cause such an event to happen?

There are many faults along the western coast, and they will not break all at once. M6-7s under the cities are dangerous in addition to the M8-8s on the San Andreas system and the Cascadia subduction zone. The past is a clue to the future. Great earthquakes on Cascadia happen every few hundred years, M8s on the San Andreas maybe every century, and M6-7s in the urban areas every few decades. - John

Hi guys! Very nice AMA initiative. I am from Chile, and everyday we experience earthquakes. What are your thoughts about prediction of great scale earthquakes?

We have very cool seismologists. Here I'll paste a link of a paper. What do you think of that?

https://www.ann-geophys.net/36/275/2018/angeo-36-275-2018.html

Thanks!

Earthquake prediction is going nowhere so far. Nothing in the solar or terrestrial magnetic fields has correlated with impending earthquakes.

Big earthquakes have aftershocks - those we can forecast in a probabilistic way, and occasionally an aftershock is bigger than the initial main shock. Also, sometimes we can notice ongoing slow slip or earthquake swarms that might make it slightly more dangerous, but not enough more dangerous to take evasive action. - John

I've heard some people say "These small earthquakes are relieving pressure over time so the big one wont be as bad." Is there any truth to that?

No. It would take 10 M6s to relieve the same stress as one M7, or 100 M5s or 1000 m4s. Little earthquakes make little change in the stress in the ground. - John

What's been happening lately in your areas regarding building standards and emergency preparedness?

In many cities and jurisdictions on the West Coast there have been mandatory and voluntary retrofit ordinances that communities have put in place to address vulnerable building types like unreinforced masonry buildings as well as enacting higher performance standards for critical structures like hospitals and other emergency response structures. Another growing movement is the idea of community resilience. The building code requirements are intended to protect life safety, but communities are now thinking about higher performance standards to speed recovery after an event. This includes things beyond just buildings; infrastructure, utilities and services as well. The goal is to help ensure people have a safe place to live after an event and businesses can resume operations more quickly. -Emory

I work in an unreinforced masonry building that has been identified by the city as a risk. It’s an open space without chairs or tables and often holds 25-100+ people. My colleagues think we ought to evacuate the second the shaking starts. I think we’re better off Dropping and Covering and waiting for the shaking to stop before we evacuate. What do you recommend? And in an open room like that, would it be better to drop along a wall that might crumble or in the middle below a ceiling that might come down?

Thanks!

The recommendation is to Drop, Cover and Hold on. You want to find a sturdy table to get under to protect from falling debris. One of the main reasons you don't want to evacuate immediately is because often the parapet (top part of the masonry walls) and other elements of the facade will fall to the sidewalk below and become a greater risk for injury. - Emory

What do attenuation curves look like in the PNW? If a 9 points EQ happens in the CSZ, which is around 100 miles away from the coast, how long and how strong would it be felt in Seattle, which is about 200 miles away, with the Olympics acting as a buffer in between? How far into the continent would it be felt as a 5 points?

The attenuation of seismic waves is greater ( it is more lossy) in the tectonically active west coast than in the less active regions to the east, and that does matter. The waves from Cascadia would be greatly diminished on the way to Seattle, about an order of magnitude, depending on the frequency of the waves, but the long duration and very energetic earthquake rupture in an M9 mean there would still be strong shaking in Seattle.

I'm not sure how far inland the intensity V contour would extend. EMD has some scenarios online that should show this map. — Brian

How at-risk is the Washington State coast from a Phuket 2004 / Sendai 2012 style tsunami? What can someone do if they are in Ocean Shores, Westport, Grayland or Long Beach?

Washington is at risk from tsunamis from both the Cascadia Subduction Zone and crustal fault earthquakes such as the Seattle Fault. Our models show that there would be significant tsunami inundation (on land flooding) from both events. The tsunami inundation from the CSZ event is more severe on the outer coast while the Seattle fault event has a bigger impact in the Puget Sound. The best thing to do is to study the tsunami hazard maps, learn your evacuation routes, and be an advocate for vertical evacuation structures.

https://www.dnr.wa.gov/programs-and-services/geology/geologic-hazards/tsunamis/#preparation-and-evacuation.6

Corina, WGS

I have thought about this myself. Honestly there’s not much you can do out there besides jump on a boat and ride it out on the water. All of those places are barely above sea-level. I stayed in Westport and Ocean Shores often this past year and I felt the only way to try and avoid demise is by finding higher ground in a building.

That's why we're working on vertical evacuation structures on the coast. Long way to go to get the coast covered but we have a few projects in the works now. https://mil.wa.gov/tsunami -- Steven

How structurally secure are the buildings that claim to be able to withstand a 7.0 earthquake? How do they test the structural integrity of a building?

Wangicus, thanks for your question. First a little bit about earthquake magnitude vs. what buildings are designed to withstand. The Richter scale magnitude measures the maximum amplitude of the seismic waves. There is not a direct correlation between measured earthquake magnitude and building design requirements. Buildings are designed to resist expected ground motion and acceleration based on several things like the soil conditions at the site and the distance from a fault. The building codes are intended to protect life safety so you may still have damage to the structure after an event.

For most buildings, the structural integrity is evaluated through analysis knowing the performance of the various building materials and the lateral system used (shearwalls in the case of a home). With advancements in computer modeling, more complex structures are essentially tested virtually with a 3D computer model. In rare cases we are able to actually test a full building on a shake table. We've been involved in a few of the biggest. You can watch them here.

NEESWood Capstone 7-Story Test

UC San Diego 4-Story Test

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-Emory

How long will the pnw be without electricity and water?

Hello, small dinosaur -
When it comes to how long power will be out after a major earthquake, that depends a lot on how extensive the damage is - some of this will depend on factors like how wet the ground is, which will impact how many landslides there are - how quickly repair crews will be able to come in and repair the damage will depend on how quickly roads and bridges are able to be repaired, or have landslide debris cleared from them.
If you want to take a look at some of the expected damages and assumptions used for planning, here is the Scenario document that was used for the Cascadia Rising Exercise in 2016, the scenario is linked below. information about power outage expectations is described on pages 90-95.
https://www.oregon.gov/oem/Documents/Cascadia_Rising_Exercise_Scenario.pdf

Some areas will get power back more quickly than others, and areas with higher populations will most certainly be prioritized - but responders will be working to get it back as quickly as possible, amid months of damaging aftershocks, which could cause potentially cause further damage...

It's going to take a while - months to potentially a year or more.

We're continually working to better understand how to harden some of these systems against earthquakes, and pre-plan response so it can be quicker.

When it comes to water, running water infrastructure will also be significantly damaged, and this will include wastewater - plan accordingly. At least for drinking water, in the PNW, there is plenty of water around. We're kind famous for it. Make sure that in any preparedness kit you make, you include ways to purify water - filters, tablets, etc., so that you can make use of this natural water.

Hope this information helps - Brian

What made you pick this career?

Earthquake geophysics offers a good mix of very interesting basic science, opportunities to do field work, and ways to help the public. Also, it is cool to talk to our friends about just how poorly we are progressing on earthquake prediction and the internet nuts we regularly encounter who disagree with us (and each other). - John

For me, it was Katrina and the 2004 Indonesian earthquake and tsunami. In both instances, lives could have been saved if people had been educated and if communities had been prepared. -Althea

I recently moved right on the central coastline. I have an irrational fear that one day there will be an earthquake and we will fall into the ocean. It sounds ridiculous, but I'm hoping you can give my nonsense some peace of mind. Can that actually happen? If so, how can I prepare for my family?

The ground doesn't move very far in an earthquake, a few feet at most. A danger is landslides on steep slopes. So if your elevation is more than about ten feet, and you're not in danger of land sliding in the strong shaking, winding up underwater should not be one of your fears.

tsunamis move across the ocean at hundreds of miles an hour. but waves simply dont move that fast.

what the heck is going on here?

Tsunami waves are gravity driven waves that influencing the entire water column of the ocean, have extremely long wavelengths (~100 miles), and move very quickly in deep water as you noted. This is unlike wind driven waves that effect only the uppermost surface of the ocean, have short wavelengths (10-1,000 ft), and are much slower (generally 10’s of mph).

–Daniel Eungard (Washington Geological Survey)

What effect would tsunamis have on the rivers (say, the Columbia river going up to Portland) or the inland bays (Puget sound/Elliot bay near Seattle)? Is a tsunami coming in from the Pacific Ocean likely to move through those water systems that far inland or have any effect at all?

Great Question! Portland is far enough from the Pacific the tsunami would not make it up there but low area along the river near the ocean are vulnerable to flooding. Have a look at the Aberdeen inundation maps for example.

Here is a link to the Aberdeen tsunami walk maps which also show inundation: https://fortress.wa.gov/dnr/geologydata/tsunami\_walkmaps/ger\_tsunami\_walkmap\_aberdeen\_hoquiam\_cosmopolis.zip?1lg6s1

And the most recent study of the Columbia River done by the Oregon Geological Survey: https://www.oregongeology.org/pubs/sp/p-SP-51.htm

Here is a link to the Aberdeen tsunami walk maps which also show inundation: https://fortress.wa.gov/dnr/geologydata/tsunami_walkmaps/ger_tsunami_walkmap_aberdeen_hoquiam_cosmopolis.zip?1lg6s1

And the most recent study of the Columbia River done by the Oregon Geological Survey: https://www.oregongeology.org/pubs/sp/p-SP-51.htm

Hey guys! As a Native Californian who now resides in Florida, from a scientific perspective what would you rather deal with, Hurricanes or Earthquakes?

I'm particularly fond of the beautiful volcanoes out here, so I personally prefer living up in the Pacific Northwest, despite their risk, and the earthquake and tsunami risk - it's an exciting place to live!

All these hazards have their own unique challenges, from mass evacuations, to infrastructure damage, to economic/environmental injustice following the event - none of these disasters are easy to deal with. So I think I'll prefer living where I am with the earthquake threat, and getting prepared for the hazards I have.

-Brian

Will cell phones work after an earthquake?

It would highly depend on the amount of peak ground shaking that each cell phone tower experiences during the earthquake. Whether they would be functional is one issue, will they have access to power following the earthquake would be another. issue. For a major earthquake event it would be likely that cell networks will be inoperable for some period following the quake until services are restored.

Where service is still available, you should communicate by text message as it is a smaller data package with a higher chance of being transmitted on an overloaded network.

Also, you should designate an out-of-area emergency contact who will be unaffected by the event and can help coordinate messaging and reunification of loved ones.

–Daniel Eungard (Washington Geological Survey)

How safe are houses and buildings with active gas lines?

Are gas lines designed to shut off to the entire city in the event of an earthquake to prevent massive fires?

How should we prepare for gas leaks?

Fires after an earthquake are an additional hazard we hope to avoid. If you have natural gas into your building, consider installing an automatic shut-off valve. The gas company will need to turn the gas line back on after an event. If you don’t have an automatic shut-off valve, learn how to manually shut-off the gas. Keep a wrench duct taped to the gas meter. Share this information with your neighbors so that if you, or they, aren’t home, your homes will be protected. -Althea

How much longer till California falls into the ocean?

The part of California west of the San Andreas fault is moving north, not down. About an inch a year. Up to 20 feet during one of the big events such as 1906, if you were near the fault. Lex Luthor had it wrong.

Will the channel islands protect the california coast from a tsunami?

Hello, unfortunaltely , our professor from USC had to leave, so we cannot give you an official answer. What I can say is that tsunamis can easily travel around islands and sometimes the islands can even act as a backstop and the waves can rebound against them. Here is a link to the California tsunami maps webpage that can show you where they have mapped tsunami hazards: https://www.conservation.ca.gov/cgs/tsunami/maps

Corina

Emory Montague, R&D Engineering Manager for Simpson Strong-Tie (expert on structural engineering during earthquakes.

Well that's just perfect that Emory is here!

With all the power grid issues here in the SF Bay Area this week, I was working on my family's emergency kit, and I ended up stumbling down the rabbit hole of earthquake retrofitting houses.

Simpson Strong-Tie's PDF guide is really excellent for how to DIY reinforce your crawlspace and foundation for earthquake resistance. My 1954 raised foundation house seems like it's an excellent candidate, and my skills can handle it (and budget - hiring someone is $$$$$).

My question is - the guide doesn't show anything tying the posts to the piers under the house. It seems to me that some shaking might cause the posts to slip off the piers, causing the parts of the house sitting on those piers to fall. Is that an oversight or intentional? Does reinforcing the cripple walls help the posts stay on the piers?

(unrelated but relevant - the link to the PDF directly from Simpson Strong-Tie website seems to be down. I had to find an alternate source for the PDF)

Hi LA_Nail_Clippers, Thanks for your question. Here's a link to the latest Seismic Retrofit Guide. For your specific question, you're correct, reinforcing the cripple walls and connecting them to the perimeter foundation helps the posts stay on the piers. Pg. 16 of the guide shows an optional connection to reinforce the beam-to-post connection. If you want to add something at the post-to-pier, you might consider the FJA or FSA straps. They aren't specifically for that purpose but might work. Also if there is enough space to fit a clip like the A34 from the post to the nailer block in the concrete pier, that would help to connect them together. Please feel free to give us a call at 1 (800) 999-5099 as you get into your project. This is one of the best ways to help protect an older home like yours.

Is there a plan to place earthquake safety information in hotels and other tourist areas, if this hasn't been done already?

When visiting Christchurch, New Zealand, I found a door placard in our room that explained what to do during the ongoing aftershocks to be helpful.

Our tourist guests are often not aware of the earthquake and tsunami hazard when visiting out beautiful beaches. States are working with the hospitality industry to train employees, develop emergency response plans, and to provide information to guests. Some communities are doing a great job with outreach to hotels.

The Ocean Inn in Nehalem Bay in Oregon provides 72 hour kits in each room. The Bandon Dunes Golf Resort is another place that is being very proactive. There are many hotels that are working towards this.

What we need is for consumers to make this important. When you call to make reservations, ask about hazards in the area and ask about the hotel plans.

Oregon has a program for the hospitality industry that anyone can use. (http://tsunamisafe.info) -Althea

Earthquake insurance is expensive and is kind of a gamble. Do you all have earthquake insurance? What is "good" earthquake insurance?

Good question because a lot of homeowners and renters don’t know that earthquakes require additional insurance and are not included in their policies. Yes, earthquake insurance can be expensive but so is repairing or replacing your home. The best thing to do is to retrofit your home so that damage is avoided, but some earthquakes can damage even well-built homes. That is where insurance comes in.

The best insurance is a hard thing to define. Most have a deductible of 10-20% of the assessed value of the home, not the replacement value. You have to decide the expense you can afford and the risk you are willing to take.

We are in the process of getting earthquake insurance on our house. It was built in 1948 so I didn’t think it was insurable until it is retrofitted. But we were pleasantly surprised to find an affordable option and will be getting it set up this month. We do plan to tie the house to the foundation and strap the chimney next year.

-Althea

With all of the earthquakes happening in Western Washington, though fairly small scale, should this increase our concern for "the big one" that's supposedly going to wipe out half of Seattle? What will it's impact be on myself and my coworkers up in Everett/Mukilteo?

Small earthquakes on the coast mean little. At the most, they indicate a slight rise in the risk of more earthquakes, nothing warranting changing your plans until the earthquakes reach at least M5, probably not until they reach M6.

The truth is it is hard to know until something big actually happens. What we know is that we have seen these small swarms of earthquakes and we haven't seen a big one yet, but that doesn't mean that that will always be the case in the future.

Corina, WGS and John, USC

Do you think we will ever be able to predict an earthquake in months to years in advance? Does it require us to place the device on the tectonic plates to measure the tension?

One can never prove a negative, but predicting specific earthquakes before the fault starts to move is likely impossible without more information than we'll likely ever know.

In theory, if we knew the strength of and stress everywhere on the faults in the Earth, and the rate at which tectonic forces are loading them, we could calculate the next earthquake. But we don't - we don't know the fine-scale geometry of the faults, nor their strength and stress with a factor of two.

So we're pessimistic about prediction, although lots of psychics and nuts on the internet are not.

I'm curious about the impact of a tsunami from "The Big One" off the Washington coast. How would cities such as Port Angeles and Victoria be affected by a tsunami going into the Strait of Juan de Fuca? Would Neah Bay be screwed?

We have information on what the "big one" would do on the Washington coast on our tsunami webpage: https://www.dnr.wa.gov/programs-and-services/geology/geologic-hazards/Tsunamis#tsunami-hazard-maps

These maps will show inundation for Port Angeles and some other communities on the outer coast, but not for Victoria. Neah Bay will also see some significant inundation from a Cascadia Subduction Zone earthquake: http://www.dnr.wa.gov/Publications/ger_ofr2003-2_tsunami_hazard_neahbay.pdf

​

Corina, WGS

I guess this is already done, but

Thank you for all your of your studies and efforts. I lost my cousin on that day, March 11th, in Miyagi prefecture. I’m a Japanese university student living in Tokyo. I seriously appreciate all people who helped us in any kind of ways.

How is the tsunami education in California (in the west coast)? I’ve studied abroad in the Vermont state (obviously east coast) and people didn’t even know the system of earthquake, which was totally understandable that they just never experience it.

Are there any constant educational efforts of preserving the memory of heavy tsunami around the west coast regions? “Oblivion” is the biggest enemy for me and us. In Japan the ancestors had, has been warning us in their unique way (tsunami stone, place names, etc.)

I’m just a public information officer and by no means an earthquake expert, but I hang out with these guys all the time and just happened to be reading this when I saw your question. Because of Japanese historians, we do have a remarkable record of when a tsunami happened on Jan. 24, 1700. (That exact date). This was the last time the Cascadia Subduction Zone had an earthquake and this “orphan tsunami” came out of nowhere and did damage in Japan — which was recorded by historians at the time. USGS did a report about it which is really well done. This was recently done and that’s how we know how active our Subduction Zone actually is.

This tsunami left behind several (what we call) “ghost forests,” which are dead standing trees now hundreds of years old. The tsunami sediment is still visible by digging. People visit these forests all the time — kayak mostly. The report link above has pictures.

We also have oral histories from the Native American tribes and nations that have passed down tsunami lessons. Google raven and the whale. This one is my favorite.

Not quite the same as a tsunami stone from hundreds of years ago, but it gives you a small idea, anyway.

— Steven

What phone or computer app will truly be the lifesaver/s when it comes to timely alerts? I fear that I have apps and social media but by the time I’m told about a danger, I got less time to react.

Thanks

Good question archronin: The ShakeAlert Earthquake Early Warning system is only going to be able to provide seconds to tens of seconds of warning - That doesn't sound like much, but where it will make a lost of distance is in automatic technical uses of the system - items like automatically slowing trains, opening doors (elevators, firehouses, etc.), gas, or electricity shutoffs can make a huge difference to safety after an earthquake - preventing fires, and other cascading failures. So this can make a huge difference in the time it takes to recover after an earthquake, and the amount of injuries - This small amount of warning will be able to make a huge difference once more users are signed up for it.

As for personal protection - how well you're able to react to a few seconds of warning - Practice makes perfect. I highly recommend the Great ShakeOut as a time to practice your "Drop, Cover, and Hold On" so you can do it quickly as soon as you receive an alert.

Hope this helps - Brian

Hi Brian. Sorry, I realized I didn't specify that I was asking about Tsunami warning apps, not earthquake warning, since we all know their forecast-ability. Tsunamis, we can outrun, if we have ample warning. But aside from a local earthquake where you know its probably safer to move away from the coast just in case, other non-local events may trigger a tsunami that i wouldn't know about fast enough. I could be in a theater for two hours, and not know about an event that's a two-hour distance away. Or even in my sleep.

Sorry I didn't catch that! In Washington, we have an All-Hazards Alert Broadcast (AHAB) Siren system on the coast. These are meant to be heard outdoors, and will go off when a Tsunami Warning is issued by the National Weather Service - their Tsunami Warning System is very robust for detecting distant tsunamis (e.g., those that might begin from an earthquake in Alaska, or Japan), and can issue this type of warning a couple hours in advance.
What we recommend for the case where you're sleeping - a NOAA Weather alert radio - it can be set to act like an alarm clock, or sort of a smoke detector for alerts in your area. That would be my recommendation. Signing up for alerts from your local emergency management office is always a good idea, too - this way, when you get one alert, you can confirm it from multiple sources.

There are certainly some situations where you won't have time to receive an alert, though, which is why it's critical to recognize the natural warning signs - an earthquake may be your only warning sign. New Zealand's messaging here is "if it's long and strong, get gone!" Before a tsunami, water may seem to recede away from the coast, too, or you may hear a roaring sound from the ocean.

If a ny city size meteor hit in the middle of the ocean how large of a tsunami would it make?

If it hit land?

Air debris?

Water levels?

Some scientists have been studying the Chicxulub meteor impact and tsunami so that may give you an idea of what a meteor that size may do: https://eos.org/articles/huge-global-tsunami-followed-dinosaur-killing-asteroid-impact

Corina, WGS

We've all heard of the San Andreas Fault, but what other smaller/mid-level faults (that could potentially cause as much devastation) do experts in your field pay attention to on the West Coast?

Great question. The worst shaking I might feel here at USC would be an M7 underfoot rather than an M8 way over on the San Andreas fault. We try to map all the faults, but many of the smaller ones are undetectable, especially if they do not reach the surface. The current California fault has several hundred faults, but about half the M6-7 quakes strike faults not yet on the map. - John

I live in Humboldt County just north of the triple junction. In Japan, the maximum probable tsunami height was significantly underestimated and it topped tsunami walls and nuclear power plant protections. What are the chances this could happen in the Pacific Northwest? I wonder about our tsunami evacuation zones and how safe they are.

Hello, for our Cascadia modeling, we use the L1 scenario, which is a Mw 9.0 earthquake and inferred to be similar to the ~2,500-year event. This new modeling closely approximates the design requirements in the building code standard for critical facilities, and is more conservative (greater inundation) than previous tsunami modeling.

For more information on the tsunami evacuation zones in your area, please visit the California Geological Survey's website, links here: https://www.conservation.ca.gov/cgs/tsunami and https://www.conservation.ca.gov/cgs/tsunami/maps

-Alex, WGS

I was on the beach and there was a Tsunami warning issued but no alarms, alerts or anything reached me. Will California ever have an alert system in place ?

That is a great question, no one here is from California so we can't answer that question directly. Here is a link to an article that may have some explanations for the last earthquake that triggered a watch in California: https://www.sfgate.com/bayarea/article/Why-California-s-tsunami-watch-didn-t-trigger-12518192.php

And here is a link to the California Emergency Management website that may have more information: https://caloes.ca.gov/cal-oes-divisions/earthquake-tsunami-volcano-programs/tsunami-preparedness

​

Corina, WGS

Do you or your colleagues pronounce the T in Tsunami or is it still silent?

It is silent but deadly :)

Corina, WGS

How did you get into that kind of profession? I am also interested in specialising in the study of disaster, what would you recommend?

Hi Malcompargin,

Always good to have more people getting involved in the field! Emergency Management is becoming a major in more colleges - that's one way to get involved.

Other than that, the field of Emergency Management greatly benefits from diversity, of people, and perspectives from which to tackle the problems which disasters. Check in with your local emergency management office (a good idea to get to know them, anyway!) to see if they have opportunities for internships, etc.

Hope this helps! -Brian

What’s the correlation with fracking and earthquakes? Is it a big concern or just overly sensationalized?

I would recommend asking someone from Oklahoma or Eastern Colorado, where earthquakes are now a common occurrence, which was not the case years ago.

The connection has been proven to be statistically significant, and is known as "induced seismicity" - our actions are inducing motions along faults.

Side note, this is mainly noticed in areas where not just fracking, but wastewater reinjection - injecting water back into the ground for years changes the pressure underground which is what tends to cause some old faults to slip.

Hope this helps! -Brian

There has been scientific and government research that indicates fracking can potentially cause earthquakes in two ways:

1. Primarily, during the fracking process: “[Earthquakes] were caused by fluid injection during hydraulic fracturing in proximity to pre-existing faults.”
2. Secondarily, due to the disposal of fracking wastewater via underground injection. This type of injection is much more likely to induce earthquakes than hydraulic fracturing.

These earthquakes are rare and many wastewater injection wells are not associated with felt earthquakes. A combination of many factors is necessary for injection to induce felt earthquakes.

You can learn more here: https://www.usgs.gov/faqs/how-hydraulic-fracturing-related-earthquakes-and-tremors?qt-news_science_products=0#qt-news_science_products

-Alex, WGS

If the worst case scenario happened and the biggest plausible tsunami that is reasonable were to hit places like Long Beach and Ocean Shores, how bad is it going to get? How tall of a wall of water are we talking? How long after the quake would it hit? How far inland are they in trouble? Would those tsunami towers be able to save people?

Alright let's get to it. So, for a Cascadia Subduction Zone event (magnitude 9) our modeling shows that for the south west Washington area there would be a tsunami that hits the outer coast in about 15-20 minutes and the highest flow depth (which is on land tsunami inundation) is located at Damon point and Ocean City and is modeled to be about 60 feet. The average flow depth for the peninsula ranges from about 10-30 feet with extremes in the 40-60 foot range and lows in the 4-10 foot range.

Tsunami wave action in the area is expected to continue for ~ 12 hours.

The land surface in the area is modeled to subside significantly (on the order of 2-7 feet)

Current velocity in that area can locally exceed 35 knots

This is a link that goes over more details on this tsunami simulation and shows maps for where inundation is expected to occur: http://www.dnr.wa.gov/publications/ger_ms2018-01_tsunami_hazard_southwest_washington.zip

Our tsunami hazards webpage has more information: https://www.dnr.wa.gov/programs-and-services/geology/geologic-hazards/tsunamis#tsunami-hazard-maps

​

Corina Forson, Washington Geological Survey

Holy hell. So in other words, in simpler terms:

A minimum 4-10 foot tall wall of ocean that goes almost the width of the horizon coming in at 40 miles per hour (and that's 8.6 lbs per gallon of salt water) and it's gonna keep coming for... half a day?

I cannot fathom how any community on the coast will exist after this. The earth will be scoured bare by that much force and energy.

It is important to point out that not all earthquake or subduction zone events are the same. Cascadia has had a long history of events of variable size. If the next earthquake is one of the smaller ones <9.0 magnitude (which is statistically most likely) then we would see much smaller wave amplitudes and far less devastating impacts. Unfortunately, as there is no way for us to quantify when the next event will happen nor how large it will be, we plan for the largest considered event in the hope that the next one will be smaller.

–Daniel Eungard (Washington Geological Survey)

Hello from the southern Appalachian Mountains!

We have the occasional quake, though we rarely notice them. Are these mountains relatively safe from any major geologic events in the near future?

You guys ROCK.

Hi TransposingJons,

There is certainly a possibility of earthquakes in that area - https://earthquake.usgs.gov/hazards/hazmaps/conterminous/2014/images/HazardMap2014_lg.jpg (Map showing generalized seismic hazard over the next 50 years. Depends where in the southern Appalachians you mean, too.

When unsure about hazards, I highly recommend getting in contact with your local emergency management office to learn more - your State Geological Survey will also be a good resource to learn about any historical seismicity.

Hope this helps - Brian

Last one from me, thanks for this!

Based on the science, what are the odds a quake can trigger something bad coming out of Mount Rainier like an eruption or a full blown lahar racing towards Tacoma and Seattle?

Hello, while subduction zone earthquakes and crustal earthquakes do not typically trigger volcanic eruptions there can be earthquakes associated with magmatic processes as the volcanoes adjust and grow. These earthquakes can indeed cause volcanic activity if the volcano is primed to erupt. A great example is Mount St. Helens in 1980.

​

Corina, WGS

Thanks for doing this AMA!

I am a SF Bay Area resident. I live in the "North Bay".

My question is: If an 8.0+ were to strike on the Hayward Fault line with a relatively shallow epicenter near Oakland, what kind of damage / consequences would the Bay Area be looking at? What could our bridges/buildings/infrastructures take?

Scientists here say that the fault has been somewhat consistent with its timing of huge earthquakes and that we are WAY overdue. What are all of your thoughts on the Hayward/Rogers Fault line in general?

An earthquake on the Hayward fault would cause considerable damage to the Bay Area, serious disruption and a lot of casualties.

Faults don't really get overdue in the sense of having the odds skyrocket - perhaps the odds are as large as twice the long term average, and most earthquakes on the Hayward would be less than M8. But that fault is a concern.

Who would win in a fight? Earthquake or Tsunami?

I think they are on the same team. Altough historically in areas where we see big earthquakes followed by tsunamis the tsunami has been more devastating and killed more people than the damage caused directly from the earthquake.

Corina, WGS

Are earthquakes predictable especially the aftershocks? As in do you have any advanced knowledge that it is about to happen or has happened before people start feeling the ground shake? If so, how often is that the case? is how earlier you detect just dependent on how close your detector is to the source?

The USGS does provide aftershock forecasts following earthquakes - for example, after the July 4th Ridgecrest earthquake, one of their forecasts mentioned that there was a small chance (10 or 20% chance?) that an earthquake following it would be larger - which it turns out it was!

These aftershock forecasts are based on research from all over the world, and are just based on the probability that earthquakes will occur within a certain amount of time after the initial earthquake. They are continually getting more information on how well these work, and updating their models, so they keep getting better.
However, this is the closest thing we currently have to earthquake "Forecasting."
Earthquake Prediction is not currently possible.

But Early warning is, once an earthquake has already occurred - see the other comment on ShakeAlert. ShakeAlert is a system activated after an earthquake has alreaxdy occurred, though, so it is not prediction, but an early warning.

Hope this helps! -Brian

Will you be incorporating gravitational wave sensors into ShakeAlert? Gravitational waves travel at the speed of light (faster than seismic waves), and the detection can be 5 sigma accurate. That should accelerate the warning, and possibly be less expensive than establishing the vast number of seismic sensors.

Great idea, but practical use is years away, if ever. Sensors are not sensitive enough by many orders of magnitude, and when (if) they improve, we need to see whether the start of earthquakes can be separated from all the other signals that would be visible. Bill

First I want to say thanks to all of you for the work you are doing!! We would like to add tsunami study information to our school district hazard mitigation plan annex due in April 2020. I’m hearing tsunami studies are in work for inland Puget Sound. Is there an update when these will be complete (I’m particularly interested in the Port Susan area)?

You are correct that there is work being done for the inland waterways of Puget Sound now. I would encourage you to reach out to your local emergency manager and set up a meeting or call with WA Emergency Management and the Washington Geologic Survey. Together we can help improve your plan and include the tsunami hazard information.

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

[[email protected]](mailto:[email protected])

–Daniel Eungard (Washington Geological Survey)

What's the percentages the Cascadia Subduction Zone event starts at the southern or northern end, not the middle where Washington State is? How long would the rift break take before it traveled to the middle?

We have little idea where the next great earthquake will start, and no idea where previous events started.

Some have suggested that a persistent seismicity swarm off Newport, OR might be as good a place as any to start the rupture. Others think that since the southern half of Cascadia tends to break twice as often and the north, maybe ruptures tend to start in the south and only sometime break through to the north. Other say maybe whenever ruptures start in the north, they easily break through into the south.

Probably safe to say the next rupture might start anywhere along the coast

i once heard something but since I cant find the source I cant repeat it......If a major earthquake hit Seattle it would leave 4 feet of glass on the sidewalks. is that true?

I have not heard this report, but it is certainly a possibility that there would be significant glass on the ground given the amount of glass on those skyscrapers. The Seattle metro area is in a large basin which can amplify earthquake shaking and depending on the earthquake source (Cascadia, Seattle fault, or a deep fault) the duration of shaking could last a long time and increase the potential for damage to the high-rise buildings. We recommend that people keep closed toed shoes with them so that they can evacuate and not get cut by glass.

Corina WGS

And do not run out of the building your in when you feel the earth shake. You are safer inside. Bill

Is it because of the plates shifting away from each other, why the east coast of North America is unlikely to fall victim to a tsunami?

Or am I completely wrong in thinking I'm safe from at least that disaster in Nova Scotia?

Thanks!!

You are correct in identifying that the east coast of North America is tectonically quite different than the west. There is still an earthquake and tsunami hazard, the best example being the great tsunami of Nov. 18th, 1929. Also, there is a risk of a submarine slope failure on the continental shelf that would send tsunami waves to the Atlantic seaboard. University of Rhode Island, University of Delaware, and the USGS have researchers actively examining this hazard.

https://novascotia.ca/natr/meb/hazard-assessment/earthquakes-tsunamis.asp

https://www.usgs.gov/natural-hazards/coastal-marine-hazards-and-resources/science/atlantic-and-gulf-mexico-submarine?qt-science_center_objects=0#qt-science_center_objects

–Daniel Eungard (Washington Geological Survey)

Oh wow! Thank you for the reply. I guess I've just never searched. I knew we have to be prepared for the occasional hurricane, frequent blizzards, but I thought I safely could knock off tornadoes, severe earthquakes and tsunamis.

I always recommend checking with your local Emergency management office (City, County, or State level) to learn about what local hazards are in your area, what the recommendations are to prepare for them, and how to receive local alerts.

-Brian

If you could go anywhere in the world , where would you go?

Right now? I'd go to the Seychelle islands :)

What’s your take for all the action around China lake California?

It's on the fault system we call the Eastern California Shear Zone. It's not as active as the San Andreas Fault System to the west, but still has had a number of big earthquakes over the years. Nothing really surprising about it, aside from the claim by the China Lake military base to have had $5B of equipment destroyed and needing replacement.
It was very well instrumented, and will give seismologists something to study for years.

My mom is hyper aware of all the earthquakes that happen. She gets alerts for all of them, and clusters of them tend to freak her out. Do small earthquakes along the west coast mean anything in particular, especially with the "big one" imminent? We live about an hour away from the Oregon coast, which is why she's so concerned.

Small earthquakes on the coast mean little. At the most, they indicate a slight rise in the risk of more earthquakes, nothing warranting changing your plans until the earthquakes reach at least M5, probably not until they reach M6.

The truth is it is hard to know until something big actually happens. What we know is that we have seen these small swarms of earthquakes and we haven't seen a big one yet, but that doesn't mean that that will always be the case in the future.

​

Corina, WGS and John, USC

What's the closest you or anyone has come to being able to predict, anticipate or call in an incoming earthquake?

We don’t count luck, but the occurrence of aftershocks can be readily forecast. Lots of people on the internet claim to have predicted earthquakes, usually the same ones who think the deep state is their enemy and trying to kill them.

The Chinese actually predicted a deadly earthquake and saved a lot of lives in 1975 in Haicheng, but in hindsight, it was a lucky guess. There was a small chance of a big event, and their evacuation saved hundreds of thousands of lives. An unpredicted earthquake the next year in Tangshen deflated prediction hopes. - John

John covered that well, just wanted to add that USGS Aftershock forecasts are probably the closest thing we have to "Prediction" - these are forecasts based on the probability about earthquake activity after an earthquake once an earthquake has already occurred - This is smore like a weather forecast, but provides an estimate for the number of earthquakes of a certain magnitude that will occur in that area over the next period of time (such as 20-30 aftershocks of magnitude 5 or more, 100-200 aftershocks of Magnitude 3, 10% chance that an earthquake larger than the main shock will occur ...disclaimer: I'm just making these up because I can't find an example right now, but...) After an earthquake, you can check the USGS National Earthquake Information Center's Event page on it, to see the aftershock forecast.
These tend to be fairly accurate, since they are based on huge datasets from other earthquakes around the world.
Still... just a forecast of probability of earthquakes - not earthquake prediction.

Hope this helps! -Brian

For the unaware, Alki (Al like Albert, Ki like Yippi-ki-ay, motherfucker) is a nice beach area on West Seattle with killer views.

For you guys... I've heard stories in the past, which I have no idea is true or not, but that apparently in one of the big previous major earthquakes, the Alki area apparently went up or down several feet in elevation from sea level, and that it can happen again.

If that's all true, would it be more likely that this area would be more prone to gain elevation above sea level, or would it be more likely to get permanently flooded, or some other outcome?

I've heard enough twists on this over the years that I've just assumed that Alki is either getting an even better view in the next 0-400 years, or else it's screwed.

Being on the upthrust side of the Seattle fault, Alki point would likely have some significant uplift in the next Seattle earthquake. In the last great Seattle earthquake (900 A.D.) Restoration Point, right across the waterway, was uplifted by 23 ft. This is easily seen in aerial photographs as shown in the image on the page linked below.

https://www.dnr.wa.gov/programs-and-services/geology/geologic-hazards/tsunamis#tsunamis-in-washington.5

–Daniel Eungard (Washington Geological Survey)

How at risk is the Puget Sound for tsunami? Some of the further areas such as Bremerton or Tacoma it seems like it would lose a lot of power before it hit. Any good resources to check my local area?

The Puget Sound is at risk from tsunamis from the Cascadia Subduction Zone and from crustal faults such as the Seattle fault. Recent tsunami simulations and mapping show that there could be some significant inundation in Tacoma from a CSZ event and even more so from a Seattle fault (on the order of 13 feet). Areas such as Tacoma would have about 2.5 hours before the first wave arrives from a CSZ event and only minutes from a Seattle Fault event.

Corina, WGS

In the cheesy action movie San Andreas ,starring the Rock, there is a massive earthquake on the San Andreas fault , apparently squarely on land. An hour into the movie a tsunami hits the coast of California.

Given that the earthquake energy was on land and the energy spreads outward, shouldn't like Japan have been hit by the resulting tsunami, not the point of origin, California??

Hello, this is an interesting question. The San Andreas is a strike-slip fault, meaning the the two plates are sliding laterally past each other and experience little to no vertical motion. This type of earthquake would actually not cause a tsunami by itself (co-seismic landslides might). The tsunami portrayed in the San Andreas movie is not realistic and a fantastic work of hollywood fiction.

However, a thrust fault event or subduction zone earthquake (like Cascadia offshore of WA, OR, CA, and BC) would experience vertical motion that can displace overlying water and produce tsunamis. In the event of a Cascadia earthquake, you are correct that this earthquake would generate a local tsunami on the west coast of North America, as well as a distant tsunami in Japan. The tsunami would take ~8-9 hours to reach Japan.

We also know that the last Cascadia earthquake happened in the year 1700 because a tsunami was recorded in Japan. If you would like to learn more, here is the publication that refers to this "orphan tsunami" in Japan: https://pubs.er.usgs.gov/publication/pp1707.

-Alex and Daniel, WGS

Hey guys! What do you think is the most fascinating thing about your job?

I really like getting to work on geology related issues that have such a big impact on the safety and lives of so many people. There is a high reward for doing a good job and getting the best information out there. I also really enjoy doing field work and getting to see the beauty of the landscapes that geology helps to form.

​

Corina, WGS

In my first job as a structural engineer, I really enjoyed seeing the buildings I designed get built and helping solve problems along the way. Currently working for a building products manufacturer I get to do the same thing by providing solutions to help others design and build safer structures. Part of that means we get to break things. My kids think that is all I do all day like exploding bowling balls in the lab. The testing is the most fascinating part of my job. It doesn't always go as expected, but we always learn something.

- Emory

Hi.

I'm located here: Bull Harbour https://maps.app.goo.gl/YusoKWqhpVmvYXrL8

I work there for a week at a time, on the water, not the island. The island itself is where we have to go for evacuation. Had a tsunami scare once... it sucked.

I guess my question is, How fucked am I? ☺

If I saw the right topo map it seems Bull Island has a lot of topography. If at sea, stay in deep water, but have a practiced evacuation route to high ground for when you are at home. You may also stash water and some basic supplies to your evacuation destination so you are not stuck in the rain and cold with no selter, food, or water. Remember tsunami is plural and first wave may not be the largest. - Bill

Bull

Hello, the Washington Geological Survey does not have any tsunami modeling information for the the location you linked, Bull Harbour. Here is a link to the Emergency Management British Columbia, which may be a more useful resource for you: https://www2.gov.bc.ca/gov/content/safety/emergency-preparedness-response-recovery

To get an idea of how past tsunamis have impacted British Columbia, you can also look at the NGDC/WDS Global Historical Tsunami database: https://www.ngdc.noaa.gov/hazard/tsu_db.shtml.

-Alex

What are some DIY things people can do to protect their structures in an Earthquake?

For older homes (generally those built before 1985 that are on a raised foundation) with a crawl space, this Seismic Retrofit Guide will give you some good information on how to strengthen the cripple walls and the connection of your home to your foundation. Another thing that is good to do is to look for non-structural things in your home or where you work that can fall on you during an earthquake. Anchor furniture and shelves to the wall. Make sure your water heater is strapped to the wall. What heavy things can fall from shelves and injure you? I've used museum wax to anchor all my heavy participation trophies that I won as a kid to the shelves in my man cave. -Emory

What are the immediate flood hazards on urban areas on the coast of the Columbia River or Puget Sound in the event of a tsunami? Would water level be the biggest concern somewhere as far inland as Portland?

https://phys.org/news/2015-02-outlines-impact-tsunami-columbia-river.html

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

​

Here is a link to the Aberdeen tsunami walk maps which also show inundation: https://fortress.wa.gov/dnr/geologydata/tsunami_walkmaps/ger_tsunami_walkmap_aberdeen_hoquiam_cosmopolis.zip?1lg6s1

And the most recent study of the Columbia River done by the Oregon Geological Survey: https://www.oregongeology.org/pubs/sp/p-SP-51.htm

What are the chances of a substantial landslide occurring from La Palma in the near (next 100 years) future, and what would occur if it did slide into the Atlantic?

Kinguke - Unfortunately, we're not experts on this area, but I found a link to someone who is:Check out this blog. TL;DR, the risk is overstated.

https://blogs.agu.org/landslideblog/2013/12/13/canary-islands-tsunami/

(Edit to add my name) - Brian

Is it possible to measure farts on the Richter scale?

Sounds like an opportunity for a home experiment: download an app on your smartphone that detects seismic waves, put it next to you, and well, see for yourself.

-Not Brian

No for that we use the RIPter scale :)

Does this have anything to do with that survey I threw out?

Tough to say, but this will probably also only take a moment of your time.

-Brian

Do you feel sad that you aren't an expert from Alaska?

Sometimes - they have earthquakes, volcanoes, landslides, grizzly bears, melting permafrost, sub zero temperatures, … Here in LA it is 80° today, but Santa Clarita is burning. There are pros and cons. - John

I read in an article a while back that there is a huge fault in oregon and that when it eventually shifts everything west of I5 is basically going to be gone.

​

How much of that is hype? Are there any parts of the country that people should avoid living in long term due to the risk of an earthquake or tsunami within the next human lifespan

That's quite a few broad questions. Just to answer your first, there is a huge fault offshore, the Cascadia subduction zone. No everything west of I5 will not be gone if it has a great earthquake. There will be lots of damage and destruction, but not total destruction, and most people would survive. -- Brian

My questions disappeared. Here they are again:

Will you be incorporating gravitational wave sensors into ShakeAlert? Gravitational waves travel at the speed of light (faster than seismic waves), and the detection can be 5 sigma accurate. That should accelerate the warning, and possibly be less expensive than establishing the vast number of seismic sensors.

What's the percentages the Cascadia Subduction Zone event starts at the southern or northern end, not the middle where Washington State is? How long would the rift break take before it traveled to the middle?

The new evac maps show reduced flooding for Westport, now putting the Ocosta Tsunami Evac building on safe ground, yet experts (including UW professors) tell me the building will hit by a tsunami flood, including by the fueled vehicles from the parking lot being swept into it. The Japanese AAR showed vehicles ignited in their tsunami and burned up against buildings (blowing 1/3 the roof off one tsunami evac building). What's the purpose of publishing a map that misleads the public?

Maybe refresh a couple of times. Your questions and answers to the first two are there.

Cascadia Subduction Zone events response.

Gravitational Wave Sensor in ShakeAlert response.

When will happen the next earthquake?

OOPS-

Already occured. Bill

Can you make Climate Change responsible for these phenomena?

Climate Change is responsible for enough disruption in the world. Earthquakes, Volcanic eruptions and tsunamis are not related in any way I can imagine to that crisis. - Bill