Woody Guthrie (2015)

Predicting when any individual earthquake occur is out of our reach now. Although there are some enticing recent observations from large earthquakes in Japan and Chile that earthquakes were preceded by observable deformation. Whether this is a general feature of large subduction earthquakes or if similar deformation occurs that is NOT followed by an earthquake remains to be seen.
-Paul

"Shaky" may be an upgrade in predictive ability! We can measure a lot of things that are related, though - bulging of the surface of the earth, very small earthquakes, changes in the fume chemistry of volcanos. We can't really correlate in a way that is actually predictive - the movie San Andreas notwithstanding. - HUTCH

At this point the science is not showing there would be a correlation in volcanic activity to a large earthquake like the Cascadia event. If by chance there was volcanic activity during a subduction zone earthquake, this would certainly pose a significant delay and challenge to response efforts throughout the region. However, continuous planning efforts to prepare responders and individuals on overall emergency preparedness (to include supplies for at least 7 days, communications and reunification plans with loved ones) combined with mitigation will significantly improve everybody's ability to respond. ~ Tabitha

One of the things that occurs is that the 'cracks' that form the crustal 'plumbing' for water and other liquids gets rearranged by an earthquake. The affect wells and springs, for example - sometimes reducing their flow and sometimes increasing the flow. Eruptions also depend on internal magma pressure, temperature and other factors so there's not really a direct link.-- Jim

I wrote a response to a similar question...but asked specifically about Rainier. I think it was in some other subreddit. I'll reproduce it here...

I don’t know if this has been estimated, but I doubt it. However, it is highly improbable. At least if you’re asking if shaking from a large earthquake somehow releases magma to the surface. In our experience globally there are anecdotal accounts of this happening (big earthquake followed by eruption), but making even statistical statements is difficult. And proving causation very difficult indeed. At any rate there have been many large subduction zone earthquakes and very few eruptions that could have been associated with them, so the likelihood is minimal. Also, there are 9 dangerous Cascade Volcanoes, so whatever miniscule chance of triggered eruption from a Cascadia earthquake would presumably be spread across all of them, and reduce the individual odds almost an order of magnitude! That said, there’s almost 100% chance that the next Mt. Rainier eruption will be accompanied by LOTS of earthquakes as magma works its way up to the surface, breaking rock as it goes. But in these cases the earthquakes are part of the eruptive process, not a trigger as such.

• Paul

Initial models seemed to bear out your initial understanding, however after the Japanese quake & tsunami in 2011 we had some significant results in Puget Sound - currents and surface rises in certain areas. Now Washington is conducting additional tests and modeling to evaluate tsunami risk in Puget Sound. This work is currently on-going so no news yet, but any changes to the risk profile will be incorporated into our ongoing response planning --Jim

Currently we are working on updated models for the Puget Sound region on the potential effects of tsunami waves from not only the Cascadia fault line but also the two local fault lines (Seattle and Tacoma) that have historically affected the Puget sound with tsunami waves and inundation. "Mini tsunamis" are possible in the Sound and in local lakes to be caused by not just earthquakes but large displacements of water through landslides both above the waterline and on the seafloor.
These "mini tsunamis" could cause a rise in the tides impacting marina areas and construction close to shore. ~ Tabitha

Yes indeed. We are testing an early warning system for the past couple of years in California, and past year in Oregon and Washington. We anticipate a public "roll-out" of the prototype, including the PacNW in mid-2016. The system is called ShakeAlert. More at http://www.shakealert.org

• Paul

Paul can give you a better read on the status of early warning systems, but any deployment will take time & $$ to fully deploy - for example retrofitting elevators in commercial buildings.

There is no real timeframe for 'the big one' - we really don't have a method of predicting quakes which is why preparedness is so important. -- Jim

Sure. California's prototype production system will be ready for unveiling in "a few months". Our system in the PacNW lags until at least Summer '16, as we test how to best integrate with the Californians. We are working with a diverse group of users who receive our alerts to find out how they can best use them, and what changes we need to make. This is ongoing.

I guess I should add that the system in Mexico has been operating for more than a decade, and Japan's system is based on at least a thousand seismometers onshore and now an offshore cabled sensor network. But both areas have experienced recent devastating subduction earthquakes and Japan has a huge risk. Our hazard level is lower here, but we want a system in place BEFORE the next earthquake, not installed regretfully AFTERWARD.
-Paul

Fear and disbelief. Followed by sulking resignation. Ultimately head-shaking wonder. It is understandable that people seek a scapegoat in the wake of a tragedy like L'Aquilla. And the situation was confusing and complicated, without doubt. Messaging is important. I think an important message is that just like we can't predict earthquakes successfully, we also can't predict NO earthquakes successfully. The real message that needs to be delivered is to be prepared and as knowledgable as possible about earthquake hazards.
- Paul

It depends which fault breaks, when it breaks, where it breaks. If you're in a masonry building and the big one hits, there is a much better chance that your building would collapse. Seattle EMD says, "Seattle has an estimated 819 Seattle unreinforced masonry buildings that perform poorly in earthquakes. These older brick buildings tend to be concentrated in areas expected to experience the strongest ground motion during earthquakes." http://www.seattle.gov/emergency-management/what-if/hazards/earthquake If you live in one of these buildings, you should contact your landlord and encourage them to retrofit it. -- Dave

Fun question! Short answer: we can't predict any individual earthquake, so predicting our ability to predict earthquakes is even more fraught! I think the best place to look is in deformation or little earthquakes that might precede a big rupture. One trick would be whether such deformation or little earthquake swarms take place without a following big earthquake. Then figuring out whether you can tell one from another!
-Paul

The main damage that happens to homes like these are sliding off the foundation, cracking and if you have a fireplace, the chimney may be vulnerable to collapse. Here is a video about a business owner's building during the Napa Quake that shows how you can retrofit a building like this and how it can reduce the potential for seismic damage: http://www.strongtie.com/videolibrary/earthquake.html -Emory

That's a project we're doing right now. We're moving across from region to region as money allows. There's surveys that have been done in Walla Walla & Aberdeen to start and it's now moving to Thurston. newer portables are more informed by the earthquake hazard. -- Dave

When the state went to the international building code in 2005, new construction and major remodels has to be done to the seismic hazard of that site because it makes a difference on what the soil kind is -- Jim

Q for the teacher. Did you participate in the Great Washington ShakeOut? If so, how did it go? If not, how can we get you to participate next year? -- Steven

Since most injuries are actually caused by buildings or other infrastructure (except for tsunamis), the ability of a building to allow you to safely ride out an earthquake is key to preparedness. Throughout the Pacific NW buildings have been built to various standards and areas with much older buildings are more vulnerable. Communities in the tsunami inundation zones (see Washington DNR maps) are the most at risk. -- HUTCH

Geographically, I don’t know where the hardest hit areas are to be expected. However, for the most damage, there are certain building types that are vulnerable (Unreinforced masonry [red brick] buildings that have not been retrofitted, weak or soft story wood-frame multi-story structures [3 to 5 story apartment buildings with lots of wall openings on the ground floor], older concrete frame buildings). For homes, it is important to attach it well to the foundation. Here is a helpful link about seismic retrofitting your home: http://www.strongtie.com/literature/f-plans.html -Emory

Anyone living on the coast should know and have a handle on coastal tsunami inundation maps available here -- Dave http://wa-dnr.s3.amazonaws.com/publications/ger_tsunami_inundation_maps.pdf

It is difficult to cite a specific area for being prepared/unprepared. It is more of individual responsibility. From the EQ catalog recently published for the state, there are more than 20 faults identified throughout the state. `` dave

Please reference the Washington State Seismic Hazards Catalog link here: https://fortress.wa.gov/dnr/seismicscenarios/
~ Dave

In general, historic brick and stone buildings don't fare well in earthquakes. The brick and stone don't hold up well to movement and if it is not reinforced or retrofitted, the walls can crumble and put people at risk on the sidewalks. Many of the historic buildings in Napa suffered damage during the Napa Quake. -Emory

This type of building is vulnerable to earthquake damage. It has been identified in ordinances passed by San Francisco and Los Angeles as a building type that may be required for a seismic retrofit. -Emory

The Earthquake, Tsunami and Volcano Program Manager at WA EMD will provide more information for you this afternoon. ~ Tabitha

I know of no more recent reports. But the "silence" seems neither recent nor ominous to me. It is "normal". It is what we know and observe, and have since the era of modern monitoring (say 1970s +). It is, however, puzzling. Amongst subduction zones it is possibly unique in its lack of interface earthquakes. And we'd like to know why. But we don't. A scientific mystery, that I hope some scarily smart graduate student can figure out soon. The plate boundary is definitely locked, and stress is accumulating on it as the plates slowly converge. But we don't have a high resolution picture of that since the locked area is offshore. There may be areas that aren't locked totally and other that are completely stuck (until a big earthquake ruptures them). But if patches do slip--they aren't making earthquakes!
- Paul

Great reply.

The early warning system is developing as technology and budgets allow. More information regarding the PNSN Early Warning System here: http://pnsn.org/pnsn-data-products/earthquake-early-warning ~Tabitha

Yes, I would expect there to be issues with multiple utilities after the Big One. Water mains and gas lines can rupture. There could be loss of electrical power. Typically, essential services structures like hospitals do have backup systems like power generators. -Emory

Depending on which 'big one' we mean - a Seattle or Whidbey Fault or the Cascadia Subduction Zone - the damage profiles are different. Since power systems must remain in balance - power in equals power being used (pretty close) - they have elaborate safety systems and these will likely trip , shutting off power for at least a while. In the CSZ scenario this outage may last days to weeks or longer depending on your location and power system. Some systems are dependent on outside supply and others like Seattle City Light have internal supplies from western WA dams. Particular system elements may be more or less fragile depending on the system and damage to the supply, high voltage transport and switching need to be patched before local distribution can be energized. Water and other pipeline systems will likely sustain many breaks and will take time to repair, although damaged sections might be bypassed by laying temporary pipe on the ground v.s. digging to replace damage. That is what the city of Christchurch N.Z. did to help get people back into their homes.-- Jim

Tabitha & or John is working on your question. Meantime, Brian Atwater was one of the scientists interviewed in the Oregon Field Guide show (which I also watched and thought was awesome). I wanted to make sure you had a copy of his free book called The Orphan Tsunami of 1700—Japanese Clues to a Parent Earthquake in North America. http://pubs.usgs.gov/pp/pp1707/ -- Steven

If codes were improved after the Mexico City earthquake in 1985 and buildings were built better, then the damage will be less devastating. However, if design and construction practices are the same as they were prior to this earthquake, you can expect the same amount of damage or more due to the increase in construction and population. -Emory

I would add that each earthquake teaches us something new that hopefully helps us do better next time. The engineers I worked with in Mexico after the 1985 earthquake were unhappy that the lessons they learned from an earlier earthquake in 1957 weren't fully applied to the subsequent buildings. 1985 clarified that the Lake Bed zone would resonate with a period of about 2 seconds...and continue doing so for minutes. The lessons were learned, and it is my belief that the infrastructure constructed since then will perform much better. You are lucky to live in such an exciting and vibrant city. - Paul

Unfortunately, we do not have a lot of information on Oregon's vulnerabilities, please reach out to Oregon Office of Emergency Management for more detailed information: http://www.oregon.gov/OMD/OEM/pages/index.aspx ~ Tabitha

Current projections don't show any dam failures due to a major Cascadia rupture, though this data set is being revisited because of the concern for this risk. That said, the ability to examine the data set is affected by ownership and dam type so we can't offer 100% assurance of every dam. The petroleum storage along the Willamette and Columbia Rivers is a concern and some spillage is a real potential. How bad that might be is really just conjecture; but from a response perspective we are assuming some oil spill response must be planned and are working with the USCG to outline courses of action.-- Jim

Todays models don't project a large tsunami that far south and the impacts will be at the beach or maybe any streams that run into the sound. Many Puget Sound islands have steep bluffs and are composed of glacial debris consisting of layers of gravel, sand and mud clay and they are prone to small collapses or sloughing. You would want to be back from any cliffs. Liquefaction occurs in river/stream valleys, areas with a lot of fill, prior swamps and similar areas. Prediction is tough but the Washington DNR has maps of soil types that may be helpful. If you dig a bit through the map section of their web site you'll find them. The scale may too large for your island/home but it might also provide a good guide if you can compare area just by driving around.-- Jim

There is new modeling we are currently working on with DNR to estimate the probability of tsunami waves and inundation within the Puget Sound from a Cascadia fault subduction zone earthquake. In the meantime, please reference the maps contained in this document: http://file.dnr.wa.gov/publications/ger_publications_list.pdf for maps on potential areas susceptible to liquefication throughout Washington. ~ Tabitha

An answer to a related question in this AMA applies here, too. Tsunamis in the Sound are tricky. The fundamental point to grasp is that to have a significantly large wave there would have to be a displacement of a significant amount of water inside the Sound. This could happen from vertical displacement of a steep Sound-crossing fault (the Seattle Fault, or the Tacoma Fault, for example), or from a shaking-induced slump or landslide from a more distant rupture (i.e., Nisqually, or a Cascadia Subduction Zone earthquake). These are all quite remote possibilities and I'm not sure how they compare with, say, being struck by an asteroid...but they are likely of that order. Well, maybe that's a bit over -the-top. My understanding of the Tsunami modeling studies from an offshore megathrust earthquake is that it's reach as a potentially damaging wave will be restricted to the area closest to the Straits of Juan de Fuca, so Olympia will likely be mostly unaffected (from tsunami waves, of course, shaking is a different matter).
- Paul

For immediate notification of an event there are notification systems that will provide warning, for example lahar flow sirens are placed around Mt. Rainier, audible sirens are in the Orting, Fife, and Port areas additionally a NOAA weather radio would provide warning of emergencies in the area to include incoming tsunamis and amber alerts. Utilizing these resources we recommend you map out and plan escape routes to higher elevated areas.
State agencies participate in emergency management planning; however, you are encouraged to contact your transit department to learn their specific plans in the event of an emergency.
First Responders and teachers in the state of Washington do receive training on the disasters and risks within their communities.
Currently we are not aware of an interactive map app at this point in time. However, this is a great idea and we are aware of similar tools recreational hikers use like "locator" beacons this may be an idea if funding becomes available.
These active and legacy pollution and hazard sites could pose a risk; however, these sites have emergency plans in place to respond during an event. ~ Dave and Tabitha

Spokane has a definite earthquake threat. A 5.0 earthquake in Spokane could cause some kind of noticeable damage KXLY story: http://www.kxly.com/news/spokane-news/usgs-new-fault-line-runs-through-heart-of-spokane/23766198 -- John

If the building was pre-1985, it needs to be retrofitted. -- Dave

PNSN had the entire Seahawks Stadium jump and shout and it showed up! More info here: http://pnsn.org/seahawks -- Steven

One answer is the experience that we had recording crowd movements at Seahawks playoff games http://pnsn.org/seahawks. I once (in a VERY quiet environment) watched a friends heartbeat as he stood several meters from a very sensitive seismometer in Khazakstan. I'm saying it all depends on how far they were jumping from the seismometer, whether it was "noisy", and what type of seismometer it was--sensitive or only tuned to record big motions (a "strong motion accelerometer"). There's not one good answer, in other words, but a range. In general, we often test a station when we visit it, by performing a "stomp test" nearby (5 meters?). And we often see people or other wildlife at our quiet remote sites.
- Paul

That might be a possibility. Appreciate the idea. -- Steven

Earthquakes are a real serious threat. If we were to get a 9.0 quake followed by a tsunami, some areas of the state could be cut off for several days. We're asking people to be prepared for at least 72 hours, but if you know you live in a tsunami zone, make sure you have enough food and water for up to a week. To get the hype, they have to show the doom and gloom, the cracks in the earth, the Space Needle falling, etc. (Although the Space Needle is pretty earthquake sound). Just noting that the San Andreas movie had some positive points, but also had a lot of seismologists concerned about the science. -- Dave

Short video on earthquake threat: https://www.youtube.com/watch?v=RMpkFvbCIis
Tsunami inundation maps: http://wa-dnr.s3.amazonaws.com/publications/ger_tsunami_inundation_maps.pdf
Preparedness Info: http://mil.wa.gov/preparedness

Earthquakes have been known to cause landslides, WA DNR is currently working on updating mapping of potential mudslide/landslide areas throughout the state. Jim is working to provide additional information. ~ Tabitha

In larger earthquakes landslides are a distinct possibility, though so many factors enter into modeling the risk it is impossible to give you a direct answer. You might look at the current LIDAR maps of your area which will show some historical landslide activity and that will be an indicator. Local building departments may also provide current landslide risk information. Major earthquakes are rare in a single person's lifetime, but if you are bothered such that it affects your life then moving to a another house might help reduce your concern.-- Jim

It is recommended that folks drop, cover and hold on during an earthquake. For unreinforced brick buildings, there is an added risk of injury for anyone who is outside on the sidewalks from falling bricks. As for the log home, I think it would perform pretty well similar to other wood frame homes. -Emory

Yes, in case of an earthquake you want to get under something sturdy. In a properly done seismic retrofit, the risk of collapse of the overall structure is less because the intent of a retrofit is to vertically support the building. However, the walls may still have damage or could collapse. -Emory

Will see if John might know the answer to your well. That is a good question. -- Steven

The King County liquefaction hazard map is online at:
http://www.kingcounty.gov/services/environment/water-and-land/flooding/flood-control-zone-district/local-hazard-mitigation-plan-update/hazard-maps.aspx#liquefaction
On our (PNSN) website, there are links to more detailed studies:
http://pnsn.org/outreach/hazard-maps-and-scenarios/eq-hazard-maps/liquifaction
Hope these help!
- Paul

Jim is working on your question. In meantime, here's a great KUOW article on the Seattle fault with great maps and graphics -- Steven

http://kuow.org/post/seattles-faults-maps-highlight-our-shaky-ground

A serious move/rupture on the Seattle fault will be very damaging in Seattle and the surrounding area (see Cascade Regional Earthquake Workgroup site at http://www.crew.org/earthquake-information) and the current track of that fault runs basically right through the middle of Seattle. It would potentially disrupt all major N/S roads, key lifelines like gas pipelines, power distribution and communications systems. The rupture would likely be 'closer' to Seattle - about 30-40 miles deep v.s. 120 miles or so from the CSZ subduction fault. The most damaging CSZ scenario is a 'progressive' rupture of adjacent fault segments ultimately extending the full 800+ mile length of the CSZ subduction zone. The will involve shaking for many minutes and, even if the energy is somewhat dissipated by distance and the current estimate is for a 'Nisqually-level or shake' in the Seattle area lasting 4, 5, 6 or more minutes. that ongoing shaking will also be very damaging in the Puget Sound area. The Japanese shake lasted about 6 minutes!-- Jim

Hi Eric. The most beneficial and economical thing you can do for older homes is attach it to the foundation. In terms of budget, we can't answer that, but you can contact a few contractors who specialize in seismic retrofit work to give you an estimate. Here is a homeowner checklist you can use to determine whether your house is properly connected and reinforced to withstand an earthquake. http://www.safestronghome.com/earthquake/03.asp -Emory

Yes it would be beneficial to participate, since Eastern Washington does have earthquakes. You can use an interactive website on earthquakes in Washington visit: https://fortress.wa.gov/dnr/seismicsecenarios. By taking preparedness actions (Make a Plan, Build a Kit, Get Involved), you will be better prepared for our other hazards such as wildfires, winter storms, and power outages. -- Rosanne

The seismic hazard in eastern Washington is indeed lower than west of the Cascades. But it is not negligible. A recurrence of the 1872 Chelan earthquake (M~7, probably) would impact a broad area of north central Washington. And there are large active (although only slowly moving) faults that traverse the Yakima/Richland area. The hazard is only moderate, and the odds of a damaging earthquake in any given day, year, or even decade are pretty small. But an annual exercise like ShakeOut is a really excellent way to keep yourself knowledgable and prepared!
- Paul

ShakeOut is the third Thursday in October. We've participated the last 4 years and had 1 million people register. If you can't do it today, then we want you to schedule a time that works best for you. You can register here (and get sent reminders next year if you want) http://www.shakeout.org/washington/ -- Steven

It sounds like you have a good idea about the basics. Steel framed buildings will likely fare better than buildings of other materials such as concrete, brick or stone of that era. The shaking will be more intense on the 8th floor than on the 2nd floor so it is important to protect yourself under a sturdy desk away from falling objects and flying glass. Anchor bookshelves to the walls and look for heavy objects that can fall and injure you. -Emory

They had an exact date because, As Atwater's book talks about, there were Japanese writers that actually had logged the exact date that had a tsunami. They called it an Orphan tsunami because they had no idea where it came from until Atwater was able to use science to figure it out by digging into the earth and discovering a "ghost" forest off Copalis in Grays Harbor County. The forest -- freestanding dead logs -- had been there for centuries, untouched and people wondered where it came from. Atwater did amazing work. It's a win for science. Great Smithsonian Magazine article on it here: http://www.smithsonianmag.com/science-nature/future-shocks-83897640/?no-ist

Dependent upon where the EQ is located, the surrounding areas may be susceptible to liquefaction of the soil. Please reference DNR's Publications of the Washington Division of Geology and Earth Resources here: http://file.dnr.wa.gov/publications/ger_publications_list.pdf
~ Dave

For soils susceptible to liquefaction, that effect stops once the energy pulses (the earthquake shaking) stops. The quicksand effect generally does not remain after the shaking stops and the soils will mostly return to their prior structure.-- Jim

WSDOT has prioritized and retro-fitted bridges and overpasses along major interstate corridors in an ongoing effort within budgetary constraints.
There are plans in place to utilize aircraft and watercraft to provide support and critical resources if it becomes necessary.
Local jurisdictions are encouraged to prepare to immediately respond in the event of a large local event to include retro-fitting public infrastructure to ensure public safety. ~ Dave and Tabitha

In general, single family homes fare pretty well. If the level of shaking in your area is high enough, a home can slide off of its foundation if it is not bolted to the foundation. Proximity to the earthquake epicenter is a factor to the level of damage. It is possible that damage to a home due to an earthquake on a local fault could be worse. -- Emory

It's a good thing it's being torn down and replaced -- and that's why it's being done because of the seismology concerns. Even though it's been retrofitted, it's still not strong enough -- Jim

I think the more important question is how that probability compares with surviving a commute on the Viaduct. Well, somewhat more seriously, the potential of collapse of an individual structure -- and then of the fate of individuals on it -- is hideously complicated an uncertain. It all depends on the shaking level (and frequency) of the seismic waves, the potential of the ground its supports are sunk into to liquefy and fail to support them, and so forth. And those in turn are affected not only by how big and how far away the earthquake is, but where it starts and how the rupture propagates along it, and where the energy enters the Seattle Basin and reverberates around, and ... you get the picture. I'm sympathetic with the idea of tearing the damned thing down ... it seems simpler than doing the uncertain and complex math ;-)
- Paul

Yeah, this has been considered. Moreover, it is clear that we can "create" earthquakes by lubricating faults, as all of the induced earthquakes in Oklahoma, Kansas, Texas, etc. now demonstrates. And those earthquakes are relieving tectonic stresses, no doubt. The problem is that we really don't understand the physics of earthquake ruptures, we don't know how to control them--particularly if there we start one up on a big long fault. There's a good chance we'd create a "runaway" rupture that would be as big--or bigger?-- than the one we were trying to prevent. Until we understand the faulting process better, and have a good impression of the state of stress around dangerous faults, we'd be foolish to try to do a "control rupture" experiment.
- Paul

The damage projections from a 9.0 Cascadia rupture are pretty scary; and in the immediate aftermath a lot of people will need help from their neighbors, friends and co-workers. But most people will survive and help will begin coming from all over the world. There are presentations in different communities regarding the projections (I don't like to call them predictions - as scientist will tell you all models are wrong to some degree) from a 9.0 (MMS) Cascadia rupture and that is the best place to get information about this really complex answer. Being prepared makes surviving the quake and the period of relative isolation afterwards much more survivable. Every catastrophic disaster impacts the damage area for very long periods of time so part of our planning includes priorities for recovering as a region. -- Jim

True that (sensationalism).
A good start would be to peruse the CREW (Cascadia Region Earthquake Workshop) scenario for an M9 megathrust event...
http://crew.org/products-programs/cascadia-subduction-zone-earthquakes-magnitude-90-earthquake-scenario
For ongoing research look to the NSF-funded "M9" project..their website is: http://m9.ess.washington.edu/public/M9_Home.html
- Paul

We just won't know. Thousands of earthquakes happen a year in Washington, but they don't always get noticed. -- Dave

You should at least have a Go Kit. -- A backpack with minimum water and food supplies. Quick video helps you figure out supplies you may already have in your house. https://www.facebook.com/WashEMD/videos/vb.123602574448465/656380481170669/?type=2&theater

As a native Pacific Northwesterner, whenever I travel to the Midwest I'm always really concerned about tornados. On the other hand I have direct experience with at least 4 earthquakes including the great Alaska earthquake that caused some swaying down in Seattle where I was. I am NOT an engineer but let me see if I can get started on some answers. For Q2 - drop cover and HOLD ON is your best bet no matter how strong. At 8.5 or stronger you may not be able to stand, anyway. Don't run outside like you may have seen others do. You are very likely to survive the quake as long as your building does. For Q1 - engineers routinely calculate the forces on structures - wind is a big one - and the response of a structure to forces is also calculated. An earthquake has up/down components and side-to-side components, each affecting the building differently. For several decades (exact date - not sure) Seattle has been incorporating seismic risks into their building code. Generally buildings constructed since the 1970s are likely to be survivable places for the inhabitants. The building may be 'totaled' but it will be intact enough to protect you if you don't have a file cabinet fall over on you - in modern buildings the contents are a big element of the risk. In your living and work spaces you should attach heavy objects to the wall and often furnishing makers provide a small screw and wire or zip tie to do just that.-- Jim

Answered this elsewhere, but repeating for your convenience.

Seattle is looking at new policies regarding unreinforced masonry buildings. You can learn more here: http://www.seattle.gov/dpd/codesrules/changestocode/unreinforcedmasonrybuildings/whatwhy/

If the building was constructed before 1985 and not been retrofitted, it's more in danger than one built later.

Oregon State just did an evaluation of the tsunami risk for the Columbia River that you can check out here -- Steven http://oregonstate.edu/ua/ncs/archives/2015/feb/study-outlines-impact-tsunami-columbia-river

Stay off the freeways, and you'll improve your chances immensely!
- paul

I'll flag this Q to have John Schelling answer when he gets back -- Steven (EDIT: John's meeting ran late and he will answer tomorrow morning)

There was a swarm of earthquakes in Oklahoma today, too. Just the way the earth works sometimes.

Our experience is that people pay attention only when there is something to draw their interest. An earthquake or a New Yorker article, for example. The fall-off in interest follows a power-law, like the decay in the rate of aftershocks after a mainshock. This AMA is drawing perhaps about 1/4 of the interest of a similar one held a couple of months ago just after the New Yorker article appeared. As far as Oregon goes. The Pacific Northwest Seismic Network that I represent is a collaboration with UO and UW, and is State agnostic. True I'm at the UW, but apart from this Saturday when Oregon's football team will be in town, I wish no Oregonian ill!
- Paul

Actually, Paul, when he was answering questions, did know things about Oregon. It's why we brought him. The Pacific Northwest Seismic Network represents both Oregon and Washington and when he saw Oregon Qs he answered them. More info on his group here: http://pnsn.org/ He was just here for the first two hours. We decided to come back and answer leftover Qs we saw. Our structural engineer Emory also was able to answer any kind of structural engineer Qs from throughout the PNW (although we had a specific Oregon bridge Q we couldn't answer. Sorry).

As for engaging the public, we really love the Great ShakeOut. It's in Oregon. it's in Washington and it gets tons of media attention. More info at shakeout.org. It provides a good annual dose of earthquake preparedness ideas. We'd love people to think about it everyday, but know that's not always a reality. I used to live on the coast of Washington. I lived with the thought of a tsunami coming at me and was on pins and needles a few times when we had alerts. Such a scenario was not fun. But I loved living there and still visit often. -- Steven

All areas of the PNW are vulnerable to earthquakes. Here's a good map that shows even Eastern Washington has been vulnerable to earthquakes. http://mil.wa.gov/emergency-management-division/hazards/earthquake

That said, there are some areas that are more threatened than others during a big 9.0 Cascadia Earthquake. Our National Guard has plans in place to have an emergency center set up in Spokane, for instance, because Eastern Wash. (and likely eastern Oregon) would be less vulnerable to a big earthquake -- but would be our main places to set up places to go back over the mountains and help those in need.

Not sure where the mapping is to answer this Q. I'll have John tackle this in the morning. -- Steven

We freaked out a bit, too, when we saw some of the comments in the article and realized the headline said Seattle -- and none of us were quoted in it since it was 99% about Portland. That said, the advice is 2 gallons of water per person per day you think you might be out of water. Your question is complicated because, let's say we get a 6.8 in Tacoma similar to the Nisqually Earthquake. Some water systems might go down depending on infrastructure and depth of earthquake. But if we get a 9.0 earthquake on the coast, it would be much more challenging. There would be destroyed roads and destroyed infrastructure. Oregon Public Radio just did a social media campaign recommending 14 gallons: https://twitter.com/OPB -- Steven

Seattle is looking at new policies regarding unreinforced masonry buildings. You can learn more here: http://www.seattle.gov/dpd/codesrules/changestocode/unreinforcedmasonrybuildings/whatwhy/

If the building was constructed before 1985 and not been retrofitted, it's more in danger than one built later.

The portable structures will (are supposed to be) built to the code in force at the time of the construction - generally speaking. Newer models are built to codes that consider earthquake risk in the design standards - that is what we mean by 'informed by'. Not exactly a technical term! -- Jim

I saw the same report. We don't have any Portland bridge experts here, BUT I've found the OPB report that you can watch. http://www.opb.org/television/programs/ofg/episodes/2701/ -- Steven

There are a lot of groups that are working on ways to help countries build better after an earthquake. After the Nepal earthquake, structural engineers from Miyamoto International flew there to offer their expertise and technical advice. Here is a blog post about their efforts: http://seblog.strongtie.com/2015/07/report-back-from-nepal-assessing-seismic-damage-from-aprilmay-earthquakes/ --Emory

That was a big falsehood in the San Andreas movie that just came out. USGS says, "The San Andreas fault cannot create a big tsunami like the ones that happened in Sumatra in 2004 or Japan in 2011. Those earthquakes happened on subduction zone faults, on which fault slip caused vertical uplift of the sea floor. While a part of the San Andreas fault near and north of San Francisco is offshore, the motion is mostly horizontal, so it will not cause large vertical motions of the ocean floor that would generate a tsunami. Earthquakes on other faults offshore California as well as underwater landslides triggered by strong shaking can create local tsunamis, some of which may be locally damaging."

During a Cascadia earthquake and tsunami, many roads may be damaged. That's true. BUT There are multiple kinds of tsunamis. First, understand the difference. This video takes 90 seconds to watch. https://www.youtube.com/watch?v=GNDsJoXgdrc&list=PLaYp9JZofBz26XydBvDbhgYmeedbS_Za4&index=5

Next, remember that Chile earthquake that just happened? If we would have gotten a tsunami, we would have had many, many hours of warning and would have been able to notify you. Please sign up for your local emergency notifications and get a NOAA weather radio to make sure you are warned. Notification alerts here: http://mil.wa.gov/preparedness

If we just have a short time to notify you, it might be better to get out of your car and get to high ground. If that means walking or running an hour, it may save your life. Understand your local evacuation routes. http://www.dnr.wa.gov/programs-and-services/geology/geologic-hazards/tsunamis/evacuation