"Giant, Underestimated Earthquake Threat" (CSZ)

I've read a lot on the Pacific Northwest's Cascadia Subduction Zone earthquake peril, but this article is very interesting. Published online yesterday.

http://discovermagazine.com/2012/extreme-earth/01-big-one-earthquake-could-devastate-pacific-northwest/article_view?b_start:int=0&-C=

Based on historical averages, the southern end of the fault—from Cape Mendocino, California, to Newport, Oregon—has a large earthquake every 240 years. For the northern end—from mid-Oregon to mid-
Vancouver Island—the average “recurrence interval” is 480 years, according to a recent Canadian study. And while the north may have only half as many jolts, they tend to be full-size disasters in which the entire fault breaks from end to end.

With a time line of 41 events the science team at OSU has now calculated that the California–Oregon end of Cascadia’s fault has a 37 percent chance of producing a major earthquake in the next 50 years. The odds are 10 percent that an even larger quake will strike the upper end, in a full-margin rupture, within 50 years. Given that the last big quake was 312 years ago, one might argue that a very bad day on the Cascadia Subduction Zone is ominously overdue. It appears that three centuries of silence along the fault has been entirely misleading. The monster is only sleeping.

So California drops into the sea. This is how a problem, beyond not having to print " The state of California considers certain chemicals in this product to cause cancer" on every damn thing?

Actually, it is the states of Washington and Oregon, not California, that appear to be at greatest risk.

HJ

Yer wrong. California lives. It's the rest of North America that sinks.

Actually a good chunk of California is moving north. California is the new Alaska.....

Briefly. If that happens Astute will be dispatched to finish the job.

Dagny,

That statement is a complete misuse of the concept of recurrance. The average interval between earthquakes is subject to an enormous amount of variation. Even if there is a 37% chance in the next 50 years, if it does not occur in that time, the following 50 years still have only a 37% chance (given no new data).

Respectfully,

Jerry

"DOWN PERISCOPE!!!!!"

Ha! Good one Mr. Ratcliffe!

Actually, if California breaks off and floats far enough away from the US west coast, it might be able to reattach itself to some of those nutcase countries on the other side of the world where it would feel more at home. North Korea would be good.

I'd hate to see Oregon and Washington go though...

An no, Californians, ... it's not you. It's your stupid politicians.

http://www.youtube.com/watch?v=Yukp0bPkQxs

It is interesting to see all the California bashing in a thread that involves the Cascadia Subduction Zone, which is centered in the Pacific Northwest, basically Oregon and Washington. I suppose that California is indelibly associated with earthquakes in the popular mind, at least in the USA.

Two of the largest shakes, the 1964 Alaska quake, and the 1812 New Madrid event, in the lower Mississippi valley, had nothing to do with California directly. California is generally more active, although the large events here, historically at least, have been of somewhat lesser magnitude. What is of direct interest to Californians is the historically quiet southern third of the San Andreas fault, which hasn't moved in recorded history, and is therefore somewhat "overdue" Fountain's caution with respect to this concept are absolutely correct.

So, if one happens to live in California, you don't need to go to Las Vegas to gamble. Just wait for the next Big One. And while you are waiting, take comfort that Las Vegas is getting closer all the time.

"So California drops into the sea."

I've actually got a large surfboard resting on the side of my house.
Ready to go, captain :-)

Pete2

The Casscadia event is getting a lot of attention in Oregon.

The drum beat is getting louder.

In Central Oregon (the Bend Region) a big concern is that should a major event occur a lot of people from the western half of the state will try to evacuate here.

The Red Cross doesn't have the supply support or materials in place to manage such an event.

Blake

www.outdoorquest.blogspot.com

Goodthing Prineville is close by,California's Home Depot stores get 99% of their Plywood from that town.

I lived just west of the Los Angeles area in the adjacent county during the 1994 Northridge quake. Our locality lost power for a day. There was no discernible movement of refugees out of Los Angeles into our area. When you think about it, how do you "flee" an earthquake... After the event. most people will try and patch up and rebuild, although U-Haul traditionally does great business in the weeks after a big shake - people moving to Kansas to avoid quakes. I have talked to ex-Floridians who have moved to SoCal to avoid hurricanes - talk about jumping out of the frying pan into the fire.

Migrations / self-evacuations after a quake depend entirely on the scenario - a 9.0M CSZ quake in November-February when the temps are 32-42 F and its wet out may cause a lot of displaced to try to get away. The focus of the initial response is to shelter folks so they don't die, then its like running a farm - feed them and water them and handle their sewage. You want your house to remain habitable, but if it doesn't crowding in with neighbors or in a nearby church, school or community center to get out of the rain will do, believe me. Ask yourself, if you're lucky and your house survives a 9.0M, are you really going to turn away the neighbor - or stranger - at your door? July when you can survive over night and not get rained on gives you more possibilities - as long as you can eat and have something to drink, you probably are going to stay close to home. You may send your family out to Aunt Martha's, and the kids could be expected to stay 4 counties over to go to school the next year.

During the Vancouver Olympics Washington EMD and various other agencies ran a drill simulating a rapid forced migration across the border of thousands of Olympic visitors, I think the identified threat was a terrorist attack, but the logistics are all the same - how many can cross the border per hour, how fast they can travel, how far before they need to stop for the night and bed down, etc. Dealing with any migration has a lot of similarities - how many are at risk from an event, how many are detected along major traffic routes out of the area, how far can they travel before they have to bed down. You open shelters and offer assistance along those routes, people will stop, or find their own shelters, food and water. I can believe that Bend OR doesn't have the resources to assist Western Oregon after a CSZ event, but then neither does anyone, not without a bit of planning.

From just an earthquake? Probably no sudden mass migration. But if we're talking CSZ, a tsunami or series of tsunami could flood hundreds of square miles of coastline and push people inland in a hurry. Or a strong earthquake near Sacramento, CA could collapse the extensive levy system there, flooding much of the metro area and causing people to flee. And under the right conditions, a big, out of control wildfire could have a huge front that forces many thousands to flee in a hurry.

A slower unfolding but also plausible scenario is a shortage of water in Southern California if the water supplies imported from Northern California and Colorado are disrupted by a quake for an extended period of time. So, a strong quake near Sacramento or out in the desert along the San Andreas might not cause that much damage for the people in the LA/OC metro area, but severely disrupt water supplies and prompt SoCal residents to leave for greener pastures if most water imports are cut off. There are extensive local reservoirs but those won't last forever, nor are there enough ground water supplies to support everyone in the region.

Oh, and considering the ongoing troubles at the San Onofre nuclear power plant and the tragedy of 3/11/11 in Japan, a nuclear accident triggered by an earthquake could release radiation and cause a major migration. There are reports that the Japanese government considered evacuating up to 40 million people due to the Fukushima meltdown. Where do you send 40 million people on short notice?

My point was that it doesn't seem that historically earthquakes have triggered large movements of victims fleeing the scene of the devastation, but I am certainly no expert on the situation. Can someone cite examples of large movements of earthquake refugees?

According to the Virtual Museum of the City of San Francisco, three-fourths of the city's population was evacuated after the Great 1906 Earthquake:



According to this website, after the 7.9 Sichuan earthquake in China: "At least 15 million people were evacuated from their homes and more than 5 million were left homeless."

i'm surprised that folks in OR are worried about a potential evacuation from the western side of the state. I would think that Oregon has enough farms, local communities and resources to cope with displaced people. Seems like everybody should get fed - it may take a little while. But it should happen.

As far as LA goes ... I tend to think that the human response after a giant earthquake may be the dominant factor in an emergency, rather than just the earthquake itself. I honestly cannot predict how people will do. But it's not hard to speculate that families will run out of fresh water in a few days. And at that point they either fight with each other over the remaining (very) scarce resources ... or they try to get out. However, walking out of LA is no mean feat, and could be a grueling trek. Especially for families with children. An escape route going East would take them into the desert ... not attractive from a dehydration point of view. South or north might be better. It's hard to know what will happen to LA - probably depends upon whether there are large-scale fires (after the quake) and large-scale rioting.

Pete2

I guess the meaning of evacuation is somewhat hazy. According to one source, many people left San Francisco in 1906 and traveled all the way.....to Berkeley and Oakland. I think the scenario envisioned by those in central Oregon is just a trifle unrealistic - a sort of atavistic dread of "them furriners on t'other side of the mountain."

After all, we are a fairly well developed country with the ability to respond decently to disasters (Katrina notwithstanding - the record in California and elsewhere is reasonable).

Besides, I and others are CERT trained - we can leap tall buildings at a single bound - provided they have collapsed first....

This wikipedia page has some interesting information on mass evacuations back to the first century.

Also the mass evac of millions from the 2008 Sichuan earthquake is in question as there has never been any substantial numbers released by the government of China. This Google custom search has more links then you could ever read about on this particular earthquake. Also the wikipedia page on the Sichuan earthquake is very informative.

maybe we should look at the simple process of "evacuation" and be a little bit humble. Many Americans have become "creatures of the automobile". A lot of people hardly spend any time walking any significant distance at all.

I have a feeling that a lot of folks who tried to walk out of a major emergency zone ... might get into serious discomfort pretty quickly. At which point they would just kinda "shut down" and become stranded. Hence the modern day evacuation might turn into a very short exodus to the closest bedroom suburb (or town) beside the city that was affected. I pity the residents of those small towns and suburbs.

it seems to me that I vaguely recall a conversation a few years ago with someone who lived in a town just north of San Francisco. They said pretty much what I was hinting at above. The locals had some kind of plan to close off all the exits from the freeway, and compel refugees to keep moving ON - by force if necessary.

Pete2

It happened after Katrina with the town of Gretna. I think most of us probably saw news clips of it when it happened. I still remember it. I can sympathize with the Gretna mayor's perspective and the extreme situation everyone was in, but it's a very sad incident to recall.

Gretna reminds me of 9/11 when my wife worked at a major Manhattan hotel. Large corporations immediately reserved massive blocks of rooms so the hotel staff had to turn away--many times tearfully--tired and traumatized folks who were covered in ash and were trapped in Manhattan because the whole island was on lock-down. She said only a fraction of those reserved rooms even ended up being used at all. The staff tried hard to call around and find rooms at other hotels, but everywhere was booked, too. Of course, if the staff had let people into rooms blocked out for, say, JP Morgan staff, and JP Morgan found out there weren't enough rooms for them, someone would probably get fired. That incident also saddens me to remember it.

That's actually quite a journey by foot. The Bay Bridge was not built until 1936. The San Mateo bridge not until 1929. From SF to Oakland around the bay is in the range of 80 miles. On foot at an optimistic 10 miles per day, that's 8 days of travel.

One thing I always try to consider when going to see friends and family is how long would it take me to walk there. In most cases, it would be days if not weeks. Evacuation on foot is not something most consider, especially if bridge infrastructure is compromised. Add in a child or two or an elderly relative/friend and you're a long way from nowhere on foot.

i have a buddy living in coos bay (on the southern oregon coast), right in the middle of where the CSZ will likely occur. because he too is quite concerned about the possibility of this happening, i forwarded him this thread. here is his reply to me, which i thought was pretty insightful:


I've gone over this scenario many times in my head. When this M9 earthquake and Tsunami hits, all coastal cities and their infrastructure will be devastated. transportation corridors and electricity/natural gas transmission will be down. Bridges out.

I see people sheltering in place for about a week, maybe 2, until food stocks run low. Then the evacuation of the coast will begin. It may be on foot or on ATVs, but it will move toward the I-5 corridor, which will also be seriously hampered by cuts in transportation, and electricity and gas transmission.

The Cascades and high desert present quite a challenge/barrier to mass exodus of people from the coast. But relief supplies will have to come in and refugees will have to come out. Those trucks and trains probably will not run empty as they drop off loads and head back east. Many of us have family in the inland northwest or farther east. I imagine that 3 months after the CSZ rupture, the coast will be depopulated by at least 50% and the diaspora will relocate across the country, just as happened to some extent with Katrina.

As infrastructural is re-established, the diaspora will slowly return--also just like Katrina.

It is interesting that none of these scenarios apparently factor in supply/relief efforts arriving by sea. A major response by the US military and others in a substantial disaster would be a significant factor.

I thought the article abour Gretna, LA was pretty interesting.
That is exactly the dilemma.
Would a bedroom community become so fearful in a mass evacuation that they just shut everything down? Clearly ... yes.

But what about peoples' right to evacuate?
Why can't they just keep walking further - if they want to?

It's definitely a mess.
and the story does illustrate one thing - that sometimes you cannot go where you think you want to.

Pete2

Was that reaction typical and representative of the communities surrounding New Orleans? One would hope that that kind of attitude would be an outlier, ut that is probably a bit optimistic. I must say this story reinforced some opinions I have formed over the years about that portion of the country. I was raised during WWII in Hattiesburg; my first plane flight began at the New Orleans airport when we relocated to Dallas, TX, after the war. I last visited New Orleans in the late 70's during a business convention. Going for an early morning run, I was impressed with exceptional amount of trash and filth in what was supposedly a fairly decent part of New Orleans.

Needless to say, the stresses and strain involved in any natural disaster are exacerbated by prejudicial social attitudes and practices.

When I think of the South, I recall the separate white and black drinking fountains in the Woolworth store in Hattiesburg. We have gotten beyond that, but there is still room for improvement, and not just in the south.

80 miles - quite a journey? Yes and No. For some people, it would be very difficult or impossible. For experienced thru hikers, 80 miles would be less than three days journey over fairly easy terrain. I would seriously consider making a trip of that length on a bicycle, planning for about a day, perhaps two. The bike has some real advantages for evacuating - it can easily circumvent obstacles, and one can easily travel three times as far on a bike compared to foot travel, carrying equivalent weight.

Much depends upon circumstances and conditions, which will be fairly unknown when caught up in a disaster....

Anyone living on the Oregon coast ought to be making plans to camp out long-term at home, in a tent or a vehicle. Evacuation by any means to the I-5 corridor, let alone central Oregon, would be extremely daunting if not impossible.

I can't see evacuating to central Oregon from Portland, either (162 miles from Portland to Bend). Up and over Mt. Hood on Hwy 26 after a huge earthquake? No way.

I'm from Hood River Valley (60 miles east of Portland, it stretches from Mt. Hood to the Columbia River). In the mega-quake scenario that would cause anyone in Portland or the coast to consider going east of the Cascades, they may well find I-84 impassable. The rock-fall from the cliffs in the Columbia Gorge surely would be considerable. Bridges would be vulnerable. The smaller mountain pass roads? Doubtful.

It is 200-250 miles from the coastal towns to central Oregon. 80-100 miles from the bigger northern coast towns (Astoria, Seaside, Cannon Beach) to Portland.

Long before any evacuees got near the Cascade mountains, they'd have to contend with the coastal mountain range which is in between those coastal towns and the I-5 corridor. Collapsed bridges would not just block vehicles but would make egress by foot or bicycle far more difficult, too.

I graduated from Oregon State University and made countless drives to Newport - the nearest coastal town. Cannon Beach is my favorite Oregon coast town and I often go when visiting Oregon. Since becoming aware of the CSZ I have given a lot of thought to the worst-case scenario and it is very grim for tourists caught up in such a disaster. Full-time residents would at least have the benefit of their pantries (well stocked, if they're wise).

I'm among those who've long advocated the merits of mountain bikes and bike trailers in such dire scenarios. On the Oregon coast, an off-road motorcycle could make a lot of sense, too, if only to commute to the Red Cross shelters that would eventually be established.

May God help residents and tourists on the Washington-Oregon-California coasts if the worst-case CSZ scenarios occur. It will be awhile before any other help could get to those communities.

my coos bay buddy again adds his two cents:

Interesting thread. The other posters have nailed the problems with evacuation. Relief supplies by Navy or merchant marine is a nice idea, but ports have to be operational to unload ships. The ports of Portland and Seattle/Tacoma will be wrecked in the same way all other infrastructure will be. Relief supply will be slow as fuels and heavy equipment for clearing debris and getting infrastructure back online will be slow to recover. Recovery will be slow. Re-establishing transportation and utilities will be slow. Meanwhile, there will be 1-5% of the population killed in the earthquake/tsunami. 10-20% injuries. another 5% will die form injuries or disease.

There will be tough, challenging weeks for the survivors. Organizing ourselves, improvising water, food, shelter, medical care, and sanitation will be daunting tasks for people used to flipping switches and turning on taps. We will need the leadership of survival guys to help organize, prioritize, teach skills, and improvise. We will survive with hand tools, sand water filters, cook fires, and rationing food. There will be much to do, but also many hands to do the work. The more people prepare and build the skills ad knowledge base now, the better it will be when the big rip comes.

Dagney made some very good points.

Although we don't live in Oregon, we live on the northen end of the Cascadia Subduction Zone. This area shares the same type terrain, weather, infrastructure etc as other cities such as Seattle. If and when there is a 7+ earthquake here, I am under no illusion that an evacuation on foot to the east on foot to the interior would be very ill advised.

In this area, in order to travel east, there are only 2 major highways to follow that have bridges that are also vulnerable to an earthquake. If you happen to live on the eastern side of the bridges and were foolish enough to think of evacuating by vehicle, the local roads that were not affected by the quake would be gridlock and impassable.

Traveling east by foot or bicyle would even be more foolish. After a 60 - 90 mile walk through relativley easy valley terrain and assuming you had the proper gear, food water etc to make it this far after days of walking, the Cascade mountain range is now a major obstacle. At this juncture, there are 2 roads heading NE into the interior and assuming that critical bridges and tunnels have not collapsed...which many probably will of, the evac is now inherently dangerous. Here in the coast range mountains, there is often snow and severe weather well into May at higher elevations. In the summer, the daytime temperatures can reach the triple digits. Those who make this far now would have days of walking with no infrasture, no food and only a couple of very small towns and villages that would be quickly overrun with people who where driving when the earthquake hit. Although these small towns may of survived the earthquake which was 200 to 300 miles southwest, these towns would be in short supply of food etc as it has to be trucked in during normal times.

Taking Dagney's points into consideration and the above, if the big quake hits here, the odds of survival after the quake would be much more in our favor by staying put then attempting to evac on foot to a destination that is hundreds of miles away...and fraught with almost overwhelming difficulties in many forms.

My general strategy for a devastating earthquake is to shelter in place; fortunately I live near a coast which gives me a lot of option.

With regard to Oregon and the CSZ, it is instructive to think how that area was reached and supported in early historic times, before the advent of modern transportation networks, all of which will likely be disrupted by the event. Goods came by sea. That would e a reasonable way of getting help to those effected by an event of the magnitude contemplated. But hopefully one would have a good two weeks or more of food available.....

I couldn't remember the name of the place or where I read it for a while, but this (important) article about Algiers Point is another example of what happened after Katrina. Algiers Point is high ground, just across the river from the Lower Ninth Ward, although not directly accessible from there by any bridges.

You had roving bands of armed white residents basically executing any non-whites who ended up in their corner of New Orleans--and they brag about it to the reporter. The veneer of civilization is much thinner in some places than others, it seems.

So, Gretna was not necessarily typical, but it wasn't a lone outlier either when it comes to extreme outsider-vs-insider attitudes.

Anyone who is following this topic would enjoy reading this book published last year after the Japan megaquake-tsunamis. Fascinating and a reminder just how recent is the modern understanding of earthquakes and plate tectonics.

http://www.amazon.com/Cascadias-Fault-Ea...0274&sr=1-1


As I was driving around today I was pondering just what would be in my rucksack next time I visit Cannon Beach and spend hours walking on the sand. I've always stayed in hotels right on the beach and savored walking the nine miles of wide beach - from sunrise to midnight if there's a full moon.

And like many Oregonians, I've enjoyed going to the beach during winter storms as much as rarer warm summer days.

Geologists now say that you may have just 15 minutes from the earthquake to a tsunami hitting the beach. Even in my heyday of youthful fitness, I would be hard-pressed to get to high enough ground to ensure safety from the worst tsunami scenarios. But one thing is for sure: if I'm anywhere on the Pacific Northwest coast and feel any kind of tremor, I'm hustling inland and up as fast as possible. My sister and friends may or may not be with me - the closest to Cannon Beach live in Portland, 80 miles away.

In the 9.0 quake-tsunami scenarios, if I stay in one of my usual hotels, my luggage in the room and my car will be lost. So I'll be stuck with what I'm wearing and carrying. Tourists will likely far outnumber local residents (population: 1600) -- who will have their own problems to contend with.

What I think I'll have in my rucksack there from now on, knowing I won't want to be terribly loaded down when at any given second there is a miniscule chance of a megaquake hitting during my vacation:


Cash (at least $300)
Petzl Zipka headlamp-wristlamp (+ extra batteries)
UCO 12-hour beeswax candle
Pocket radio (+ extra batteries)
Oregon folding map
compass
Bic lighter + REI stormproof matches + firesteel
cotton balls + Vaseline lip balm
Doug's Mk5 and Mk1 knives
Micropur water purification tablets
titanium sierra cup
Kleenex tissue packet
AMK heatsheet
mini-first aid kit
550 paracord (my dog walking neck lanyard has some incorporated)


I can put this all in the bottom of my rucksack without adding great gobs of weight or taking too much volume. Even in summer at Cannon Beach, I'm usually wearing a jacket of some sort. Would be bad news to be stuck with just shorts if a disaster hits that could entail being without shelter overnight on the Oregon coast - brrrrrr.

By the way, Cannon Beach is not a port, so supplying emergency provisions by ship would be a very tedious task.

Helicopters would be in huge demand throughout the affected region.

In a disaster of this magnitude, it might not be unreasonable to plan for an aircraft carrier and logistical support vessels to make an appearance, along with beaucoup helicopters - not right away, necessarily, but within a two week time frame. In truly serious disasters, the military becomes involved.

Great thread!

I'm certain that you edc one but, just in case, I'd consider adding a water bottle, Dagny. That way you can start with a little potable water that you can drink on the fly. Good for hydration, first aid, etc, without having to wait for tablets, boiling, etc.

Airlift capacity has improved since the 19th century :-). Between 9.0M EQ effects and tsunamis and seiches, there's not alot of hope that the ports will be operable for a week or more, and if operable whether you can roll trucks or railroads anywhere near them to offload assistance. Haiti was a good example of a port damaged by an EQ, that took 2-3 weeks to resume some reduced capacity - and it generally takes cargo ships at least 2 weeks to get here from anywhere with needed supplies. Meantime we have I-5 and I-90 that will be crippled N miles from population centers, so trucks rolling with relief supplies and staging them for airlift into the damage area from there, modulo surviving and patched up runways at Portland, SeaTac, Paine, NAS Whidbey, Bremerton etc. Routes out to the coast may not survive tsunami and EQs. In the Puget Sound area our fabled floating bridges might be taken out by seiches, 8-16 foot waves that will rock Lake Washington like an unruly 5 year old in a bathtub. There are a zillion bridges and roads that could be taken out by landslides and shake activity. On the response side, there are Naval Stations on the Oly Peninsula and in Everett typically with aircraft carriers in port to deploy; helicopters and C-147s can be sortied from Spokane Fairchild and California as necessary to supply the area until roads and bridges can be recovered. The PNW's level 4 trauma center has an iffy chance of surviving a CSZ or other significant EQ. A CSZ event is probably a worst case scenario for the PNW, requiring not only a tsunami response along the coast but also severe damage and casualties across the interior. A CSZ EQ will require the type of national and international response we saw in Katrina. It will be a mess. Local county or state EMD are rich with HIVA analyses that are still being updated after drilling on this scenario in 2010, and taking into account new research and the outcome from the Japan EQ - http://www.kingcounty.gov/safety/prepare/EmergencyManagementProfessionals/Plans.aspx.

The reality is that while dire and lethal, the CSZ is a worst case disaster, and there will be many other less dire and lethal disasters before it occurs. Most of the EM budgets are going to an all hazards response, and to responding to the ever present reality of wind storms and ice storms and floods which happen ever year or few, and which tend to incapacitate most of the PNW almost as badly as a CSZ quake.

This almost goes without saying in this forum, but I encourage anyone alarmed by the potential of a CSZ quake to review these HIVA analyses and get prepared for the more common ones, because by doing that you are more prepared for the bigger ones. Also get involved - local responders and secondary responders like the American Red Cross, Salvation Army, Southern Baptists etc need you in the event hundreds or thousands of people need food and shelter - but also between times when folks in your community need you, right now. CERT skills may be valuable, preserving the lives of family and neighborss. Folks with ham radios who are licensed and trained and not afraid to use them will also be in demand, and as hams know the better organized you are into groups the more effective you will be in coordinating responses. That sort of thing. My perspective, we all spend alot of time responding to the smaller disasters, and while we have plans for the bigger ones that may occur every 100-200 years, our ability to respond to larger disasters comes from repeatedly responding to the smaller ones. There is a helluva lot of coordination that has to happen for folks in King or even Kitsap county to help out folks out in Jefferson or Pacific County along the coast, but frankly in the early days we won't be able to help them, let alone access them. We're all on our own for a while in a CSZ event, just like after major wind or snow storms, so it makes sense to prepare accordingly.

my coastal buddy chimes in again:

How am I going to survive it with family in the Coos Bay area? My house is as 40 ft above sea level. The newly updated inundation zone maps have the tsunami lapping at my front door. We have a pantry and water stores. I imagine that all houses will be knocked off of their foundations and utility lines will be broken. power lines will come off their poles. Street pavements will be busted up. Bridges down. If the house survives the earthquake/tsunami, and doesn't burn down in the fires that break out afterward, it will be crooked and breezy, but it will provide basic shelter from the elements.It would be condemned if there were building inspectors around to enforce that. Everything inside will be thrown around and busted up. fridge tipped over. Contents of fridge and cupboards broken and spilled on the floor. broken glass and crockery everywhere. floors covered ankle deep in crap.

We will tend to the injured. Check on the neighbors. Get organized. Inventory food and plan to use fridge food first, freezer food second, and dry/canned goods last. Clean up the best we can. Toilets/sewer lines not working, so dig a latrine in the back yard. Set up a makeshift kitchen in the back yard. Set up basic sanitation practice.

Our children go to school 5 miles away across the bay. if it happens during the week, bridge out, the parents will figure out a way to get boats across the bay to retrieve kids. After a week of improvising, a new routine will emerge. There are a lot of elderly folks living alone in houses. Maybe we'll figure some way of getting younger, displaced people and families to move in temporarily with older homeowners. The guests can help out with chores and getting potable water and fuel for cook fires, the older home owners provide shelter. Some kind of social synergy will occur.

After we get basic needs taken care of, we may find time to organize to clear roads, repair port facilities, organize shelters at public buildings for red cross and large institutions to run.

well ... if that was me in Coos Bay i would have a plan to get to high ground FAST. You will definitely feel the magnitude 8-9 earthquake before the tsunami hits. the important thing is that your whole family needs to know exactly where they are going, and they must react straight away. now is a really good time to work out those details.

when the Japanese tsunami hit there was a very interesting story about an old woman who fled the tsunami on a bicycle. I know you are thinking this sounds ridiculous - but she actually did it. of course, an old woman cannot ride faster than a tidal wave. BUT what she did - was to get going immediately when she felt the quake. so she had some lead time, and it was just enough to get her to safe ground.

having a plan, and executing it when you really need to, can be a lifesaver :-)
A good lesson for all of us.

Pete2

I think these warning stones are an interesting feature of the Japanese landscape - some of them 600 years old, reading:

"High dwellings are the peace and harmony of our descendants," the stone slab reads. "Remember the calamity of the great tsunamis. Do not build any homes below this point."

...
Hundreds of such markers dot the coastline, some more than 600 years old. Collectively they form a crude warning system for Japan, whose long coasts along major fault lines have made it a repeated target of earthquakes and tsunamis over the centuries.

The markers don't all indicate where it's safe to build. Some simply stand – or stood, until they were washed away by the tsunami – as daily reminders of the risk. "If an earthquake comes, beware of tsunamis," reads one. In the bustle of modern life, many forgot.

http://www.huffingtonpost.com/2011/04/06/japan-tsunami-warnings-fr_n_845818.html

It probably only sounds ridiculous to us car-centric Yanks. It's quite common for seniors--many very old--to ride bicycles in Japan as their main form of transportation. Maybe not so much in the crowded urban areas (heck, bicycles have all but disappeared from the streets of big cities in China now, too) but certainly in more rural areas like where the tsunami hit.

Actually, having a bicycle handy may make a lot of sense for a quick get away to higher ground depending on one's situation. Takes up relatively little space, don't have to worry about gasoline going bad in storage, roads and bridges may be jammed with traffic, much faster than being on foot, etc.