I wish people would take the California earthquake situation more seriously. We've had decades of warning yet are still minimally prepared for disaster. The sad thing is, the only way we'll see real change is after a major earthquake where thousands of people are killed/injured. Then people will fight/sue/vote for change. It's just like in the city I live in, where we have multiple known-to-be unsafe traffic intersections. Only after there's a serious accident and someone sues the traffic lights get built. It's unfortunate that even today, the cost of change is priced in human lives.
If you compare similar earthquakes California might see 1,000 deaths to a quake which would kill 100,000 people in less prepared areas. IMO, they simply hit diminishing returns where an extra million can save more lives dealing with other problems.
Humanity as a collective is comparable to cockroaches. Purely reactive to their environment, completely oblivious to the information that could make it proactive.
The rules apply to all new construction, yes. But there are thousands of unsafe buildings built in the 60s and 70s that are grandfathered into the seismic safety rules.
Some cities have made an effort to retrofit these buildings (Napa and Los Angeles come to mind) but there isn't a state driven effort to do so.
Which California are you in? My part, Southern California, we take it very seriously and so does the local government. There are earthquake drills, the building codes reflect the environment and CalTrans has reinforced the freeways over the last 20 years. Will Southern California come out unscath in a large earthquake? No, but our death and injury rate will be lower than similar quakes in other parts of the world.
There's also long been talk about a big earthquake due in central Utah. Really there are so many "big ones" due it'd be thematically disappointing if they didn't all happen at once and then set off Yellowstone as a finale. But in the real world, it's scary thinking about how many people will die and how poorly it will be handled. Anything that could cripple a large part of the US has worldwide ramifications, too. Living in the Seattle area the best I can hope for is that I'm individually prepared enough and will have the fortitude to help others around me as best I can.
When I lived in Vancouver in the 80s, they had earthquake drills because scientists said "It was too long, we're due for a Big One!" Everyone took them seriously.
30 years later, no significant earthquake, and earthquake drills are nothing but a distant memory. I think humans are really terrible judges of what "long overdue" means, especially related to geological events.
Yes, at some point there will be an earthquake. Yes, some people will die. But overreacting and worrying about it when humans have no ability to predict it is worse. The best way is just do what we have been doing, which is increase building standards, have once-a-year drills, and stop trying to predict when disaster is going to strike, because humans can't.
Having basic supplies on hand is just as important as building standards and drills. As I mentioned in another comment my family and friends lived through the Canterbury (New Zealand) earthquakes of 2010 and 2011 that destroyed much of the largest city on the South Island. Water, food, and shelter were all important concerns especially during the first 48 hours in some parts of the city. Even if help arrives quickly it can take several days for basic services to be restored.
Here in the South-East, the same thing happens with hurricanes every time there are a handful of consecutive years with no major storm. Then a large one hits and everyone gets surprised.
If this happens with hurricanes, I can only imagine how the perception of saftety/danger gets skewed with earthquakes—which occur way less frequently than hurricanes.
One of the biggest risks is older "soft story" apartment buildings which tend to collapse in earthquakes. Some Bay Area city governments are aggressively working to retrofit them.
http://resilience.abag.ca.gov/housing/softstory/
If this article is right and there is a risk of a large earthquake that will release a century of pressure buildup, it might be good to keep a week or two worth of supplies, including a bucket with attachable toilet seat lid, bag of saw dust, and a shovel to bury the waste.
If you're in a home, you might want to make sure that your supplies are more easily accessible from the perimeter of your structure in case enough damage is done that your home is not able to be entered. Ideally, a backyard shed or storage box would be the best place to store your supplies. If that's not available, in a garage near the rolling door or by a back door of the house.
If as much damage occurs to water and waste water infrastructure as they fear, and if your home becomes inaccessible, it might be prudent to make sure that you also have several changes of clothes and a pair of boots in your kit.
Basically, pretend that you're preparing for a week-long camping trip in the middle of nowhere and pack accordingly. Tent, sleeping bag, clothing, supplies, small solar panel to charge a phone, etc. It'll take a lot more space but it will make the (potential) experience a lot more tolerable.
The incredible thing is that the cascadia subduction zone is also locked, and past the average interval for moving. How unfortunate would it be if the entire west coast unlocked at the same time?
The best data we have at the moment would be records of geologic events that have a strong correlation to earth quakes and seeing how they line up between the two different areas.
My gut tells me to expect, usually not co-incidence, but as they are part of the same larger system, possible co-incidence (and likely at a much more catastrophic level when something THAT LARGE does happen).
Not knowledgeable enough about quakes to propose a study. As you and a sibling comment have stated I was just wondering if the 'they are geographically close enough and could affect each other' intuition may have merit.
I believe the fact that seismic events can trigger other seismic events along the same fault system is well known. What is still up for debate is how soon, how far away, and how large.
I've heard it said that the only way you can tell if an earthquake is a fore-shock or the main event is to wait. For example, I've always loved this visualization of the seismic events leading up to the major Japanese earthquake of 2011: https://www.youtube.com/watch?v=NSBjEvPH2j4 . See if you can identify the main quake when it happens. I bet you're wrong!
Note that this type of triggering (by passing seismic waves) is, in the absolute sense, really unlikely to specifically nucleate a M7+ earthquake; otherwise there would be chains of huge earthquakes every time there's a big earthquake in Tonga (which is all the time). However, the relative likelihood is increased substantially.
There is a lot of research on earthquake triggering (both 'static' and 'dynamic') much of which is publicly available on Google Scholar (or sci-hub...). Static (or 'Coulomb') triggering is the most physically comprehensible; dynamic triggering, where passing seismic waves cause new quakes, is statistically supported but hard to understand mechanistically. The basics of static triggering are that, if you think of the earth's upper crust as a compressed elastic (e.g. rubber, but far more rigid) sheet, when a tear in it happens (an earthquake) it changes the distribution of stress/forces in the elastic sheet. Some regions will be stressed more, particularly around the edges of the tear, and some will be stressed less. The areas that are stressed more by the new tear tend to have more earthquakes following the first one. This is largely a local (i.e. 10s of km) phenomenon.
Just out of curiosity, what does the distribution look like on the move intervals?
If your last 100 "big ones" were 100 years apart (90 times) and 10,000 years apart (10 times), your median interval is 100 years and your average interval 1000, but if you're at 2000 years you might reasonably expect another 8,000 years before the next one...
There's this idea of simulating earthquakes with explosions (possibly nuclear subterranean) in order to relieve plate movement. This should be causing mild earthquakes as opposed to catastrophical ones.
The numbers don't work out because the scale is logarithmic, and no serious seismologists appear to recommend such a thing. To avert a magnitude 8 earthquake every 100 years, you'd roughly need a magnitude 6 every year, or a magnitude 5 every three and a half days.
I wonder how many would advocate trying to have a /planned/ earthquake each 100 years? Surely one planned in advance which everyone is prepared for is better than the unknown.
If the infrastructure is up to the task and it would actually be doable (say release fault pressure with a magnitude 5 earthquake every 3 years via some sort of method) it might not be such a bad idea. Way easier to build for a planned magnitude 5.x quake every few years vs a 7 or 8 at unknown time intervals.
Heck it could even be fun. Make it a holiday, tell people the time its going to happen and let them ride it out. Personally, I'd be at a bar. :)
The general concept of prescribed forest fires has been considered good forestry practice for a long time now.
As for the actual method, nuclear bombs every few years for a large magnitude doesn't seem like it's mild enough.
We've seen that fracking often has the side effect of causing faults to get lubricated and slip more easily causing earthquakes.
Maybe research into the ideal chemical cocktail to most effectively lubricate and hook up injection stations along the length of the fault line, when there aren't aquifers in the nearby vicinity. Bonus for some kind of lubricant that degrades into non carcinogenic materials.
You wouldn't want to just start pumping fault lubricant into the system while it's so full of energy, but after the next "big" earthquake you could have a window where the pumping would trigger small size 3 or 4 earthquakes similar to aftershocks in perpetuity.
Good luck with that. My family lived through the Canterbury (New Zealand) earthquakes of 2010 and 2011 (and the 12,000+ aftershocks). Most of the CBD has been cleared and rebuilding is underway but there was/is a huge political fight over what the rebuild will look like. I can only imagine how difficult that process would be in the context of the US political landscape.
I wonder how many here realize that the only social contract (between building engineers and the rest of us in North America) is that for the absolute majority of buildings (> 99.9% of building stock) under the scenario known as the maximum considered earthquake a building shall not collapse. Meaning that any damage beyond repair or any failure of structurally non-critical components that can possibly entail lives lost is acceptable.
I live about 3 miles from a large fault line, and am OK with it - my concern is that my family does not get crushed when/if the predicted big earthquake hits. As long as that is true, I do accept that I will have a lot of repair work to do, and will lose some objects. I am not going to live my life pouring money into preserving material goods, or preserving all of my home, when I can spend that same money rebuilding, when/if that day comes.
Consider if the recovery might be thwarted by airports unable to accept arriving crews, hospitals and shelters without power and water, the fallout from a high tech hub taken out of operations for months etc. There's also the conundrum that -- because there's no metric in place to differentiate between structures that would perform vastly differently under a seismic event -- there's no rational way to estimate the damage. You may be at once overpaying and overvaluing your earthquake insurance. Your insurance has no way of reliably estimating its risks, which undermines its solvency, which unwittingly reduces its worth to the consumer. One might not be in a position to rebuild.
The issue is that our society at present does not single out life-critical operations and provide for them accordingly. The cost-benefit analysis has not been done.
Although, I don't wish to downplay the risks of the San Andreas faultline.
It seems the west-coast should be investing a hell of a lot of money in preparation for this stuff. British Columbia, Washington, and Oregon included.
If I lived in a high risk area I would invest in a 'go' bag, a mountain bike, and a plan to get to high ground as quickly as possible. You'll have about 15 minutes after the earthquake before the wave hits. Cars will be useless in the traffic. The hardest part will be ignoring the initial destruction and focusing on getting out of the area.
Although in the PNW we don't hear too much on the news, local and regional governments are planning for a major cascadia event. This June, myself and other government employees will be joining FEMA in a multi-state, multi-agency "Cascadia Rising" exercise to evaluate our inter-agency communication and response plans.
I'm curious, not being from the area but planning to move to the west-coast, does it ever come up in local political discourse? And is it local common knowledge that it will happen eventually?
Not really. I grew up in LA where everyone talks about "the big one" all the time (at least back then, not sure about now). But up in this area, no one really talks about Cascadia megathrust/subduction zone earthquakes. Every now and then there will be some news blurb or article but it's not part of the common discourse and isn't on political radars as a preparedness thing.
As a kid in that region (Portland, OR), we practiced earthquake drills in school and such, and we had a few smaller ones (I remember at least 1996 and 2001), so people who've been there long enough are at least aware of the possibility. And local building codes are written with the possibility in mind (earthquake strapping on foundations, etc). I do wonder, with all the population influx to the PNW lately, how well prepared the more recent arrivals would be...
To some extent people over-dramatize the Cascadia earthquake threat to the major population centers. The major cities are hundreds of miles from the fault line, which will substantially reduce ground motion; Seattle had a 6.8 earthquake in 2001 on one of its many local fault lines and the city is still standing. Second, some of the major cities like Seattle have greatly mitigated tsunami risk due to their location and geography. In fact, the largest tsunamis in Seattle's geological history were generated by fault lines that run directly under the city; tsunamis that reach what is now Seattle from the Cascadia subduction zone are quite modest. Vancouver is in a similar situation, though they probably have somewhat higher tsunami exposure. People that live on the outer Washington and Oregon coast will be in serious danger but that region is sparsely populated.
The San Andreas fault, by comparison, runs right through the middle of densely populated areas of California. Minimal tsunami risk but much higher ground motion risk.
More history: In 1964, an 9.2 earthquake in Alaska caused tsunamis along the outer coast of Vancouver Island. Port Alberni, at the end of the 25 mile long Alberni Inlet, was the largest and worst hit settlement, with a loss of 55 homes. Thankfully the extremely damaging tsunami was precede an hour earlier by a smaller one that resulted in an evacuation of that town. No loss of life.
Interesting. Thanks for clarifying that. I always thought Seattle was closer to the coast than it is. But it's actually just within an inlet, with Olympic National Park in between.
I'm interested in moving to Victoria, Vancouver Island, BC, which is why it concerns me. I believe that would fall into the low-medium risk category:
> People living along the outer coast of Vancouver Island will have between 15 and 20 minutes to escape. Victoria can expect a tsunami wave of between two and four metres within 75 minutes.
I live in Victoria and have looked into this before. Being an island, in most areas the land tends to rise fairly rapidly as you move away from the water. Predicted rise due to a tsunami is relatively small given the that the lower island is sheltered by the Olympic Peninsula. There has been extensive modeling done, as described here: https://www.crd.bc.ca/docs/default-source/news-pdf/2013/mode...
See page 16 for maps of predicted rise. You can compare that to an elevation map of the area, ie here with the contours turned on: https://maps.crd.bc.ca/Html5Viewer/?viewer=public. As you can see, in most areas the predicted rise of up to ~ 3 meters doesn't get you more than a few meters laterally away from the coastline.
It will obviously still be a risk, but as long as you're not right at the beach it should be ok.
For what it's worth, the 2001 Nisqually earthquake was not on any of the faults in the Puget Lowland, it was in the subducting Juan de Fuca slab, and was quite deep (57 km) which reduced the ground shaking considerably. That said there are cracks in my office walls from it, and the chem labs in the building were decomissioned following seismic damage. You are right, though, that there are a host of active faults in the upper crust in the region [1].
Seattle itself sits on the Seattle Fault (running from west of Bremerton, through Bainbridge Island, Alki Point, Beacon Hill, through Mercer Island to the east; subsidiary strands run through White Center and Issaquah), which is thought to have produced M7+ earthquakes in the past few thousand years [1]. These are shallow and surface-breaking and would be extremely destructive to the city. They are fairly infrequent (~5 in the past 16,000 years) but travel in packs [2].
Atkinson and Macias [3] estimate peak ground accelerations at ~2 m/s^2 (i.e., 20% gravity) in Seattle for a Cascadia event. Graves et al [4] (see Supplemental Fig 1) estimate PGA at about the same for most of LA given a M7.8 event on the San Andreas (which is the maximum estimated from paleoseismology and various other inferences). The SAF is 30 km from LA; the areas with much stronger local shaking are relatively sparsely populated desert regions. LA also has a lot of faults in the basin itself that are similar in size and slip rate to the Puget Lowland faults.
I think the recurrence intervals for the largest Cascadia events are very roughly 2-3 times those for the San Andreas (i.e. earthquakes are 1/2 to 1/3 less frequent).
I don't think your first point is is very strong since subduction zones don't work like transform faults. The land "will drop by as much as six feet and rebound thirty to a hundred feet to the west" http://www.newyorker.com/magazine/2015/07/20/the-really-big-...
The problem with Cascadia is that the severity of it (and it's still severe at this magnitude, even at the distance Seattle is from the fault) was not well understood until late 80s or so, and did not translate to building codes etc until 90s. So there's a lot of infrastructure in and around Seattle that is not actually built to withstand that quake. Some of it is nominally certified to survive it, but only in a sense that the building won't collapse; it doesn't necessarily mean that it will be actually usable. Crucially, this includes many large hospitals.
But, yes. The bigger problem is not the immediate damage from the quake. It's all the support infrastructure (water, power, roads etc) that will be knocked out, and may take a long time to restore.
"When the next full-margin rupture happens, that region will suffer
the worst natural disaster in the history of North America. Roughly
three thousand people died in San Francisco’s 1906
earthquake. Almost two thousand died in Hurricane Katrina. Almost
three hundred died in Hurricane Sandy. FEMA projects that nearly
thirteen thousand people will die in the Cascadia earthquake and
tsunami."
That's really nothing compared to the numbers that diseases kill every year, or the potential devastation from comets, asteroids, or nuclear war. Don't car accidents kill something like 40,000 people in the US every year? Yet life goes on. Most people don't even notice.
Yes, such concentrated destruction will be quite dramatic, and will have serious economic and social consequences, but we should try to keep some perspective.
Now, if the Yellowstone Supervolcano erupted, that would be something.
One of the interesting things I've done over the years is look at earthquakes and analyzed different preparedness strategies. Top three learnings, post earthquake living is just like camping so keeping current on camping skills and gear means you are ready to camp out on you lawn; medically trained people are easier to find than supplies put a laceration kit in your go bag, if you need it finding a nurse or doctor is easier than finding supplies; water filtration is easier than water storage, keep infrastructure that can hold water but it doesn't have to be full. That said having your cold water supply go through a 50 gallon tank means it is constantly replaced and when you shut off the water you still have 50 gallons to work with.
In my car my bag has a laceration kit, water purifier straw and, hydration bladder. Also comfortable shoes for hiking and a hat. I can walk from anywhere in the Bay Area home in 2 days so that is the prep window.
Your hot water heater is a good source of water in an emergency if it's accessible. Mine is in a small outbuilding which would likely survive an EQ so accessible without trying to enter the house.
As someone who lives near the fault in Redwood City and has an older single story wood frame ranch,Mehta are my best options for protecting my asset and life?
Is earthquake insurance worth it?
What about retrofitting for earthquakes? I've read some pretty scary stuff that even retrofits done with permits don't have much consistency between them and no guarantees. Not even sure how to find a reputable retrofit contractor because I'm not sure how to judge the quality of their work since we haven't had a big one recently.
What should my priorities be for solving for all of this?
Earthquake insurance is probably a waste for most homeowners because the deductible is so high. You would probably be better off putting that money into structural renovation to make the house better able to handle an earthquake. Make sure the frame is properly anchored to the foundation. http://resilience.abag.ca.gov/residents/planset/
The best guide I've managed to find was by Simpson Strongtie. They manufacture loads of structural bracketry used in building construction and seismic retofits.
As far as I could tell, the most important components are to make sure your sill plates are firmly attached to the foundation (with big washers on the bolts going through the sill plates or the Simpson UFP or some other plate), shear walls, and post caps. I talked to a Simpson field engineer (they actually answer the phone) that essentially confirmed this.
This is super helpful, thanks for sharing. Do you know how to go about finding a qualified person to install this stuff? I really don't know how to judge their work or what questions to ask a contractor beyond asking if they install the things you mentioned above.
If you have natural gas line connected to your house, one thing you should consider is installing the auto-shutoff valve. It would really suck if your house survives the quake, and then goes out in a massive fireball because of a gas leak.
Any contracting service is incredibly contractor-dependant (as you've surmised).
Single story home? Really look at making your own go-bag. Take a survival course, not because you'll be in the woods picking berries, but because you'll learn transferable ways of looking at the (natural?) resources around you and how you can use them to survive or thrive.
Have a go-bag in your car and by your bed (that include emergency rations and bottles / jugs of water, clean underwear, a toothbrush, etc). I bought a few cheap pop-up tents when they were on sale at woot.com. You can bet I'll be happier during a disruption of services than my neighbors who don't have even a basic set of supplies put together.
My theory is: Odds of a severe earthquake in the next 50 years are let's say 1/50. Do you spend $100k+ on earthquake retrofit, or spend $20k on insurance that'll let you rebuild? (my numbers are completely made up, btw).
Well, you have to purchase earthquake insurance anyway, and a single-family home is "less" dangerous than a multi-story home. Look at pictures of wood-frame earthquake damage and figure out what your state of mind would be after you run outside and your house ends up like this:
Figure out your go-bag situation, learn how to use it, take a survival course, keep lots of water handy, buy a tent, and then only worry about it in order to keep your supplies and skills fresh.
Since you have a house, also run a 55 gallon drum / trash can setup out in the back yard.
The insurance premiums and deductibles for earthquake insurance are sky high, so many are of the mindset that it just isn't worth it (of course regular insurance won't cover you at all in that case). Are earthquake retrofits really $100k? This guide seems to indicate they are relatively inexpensive. [1]
Ahh... figured out my miscalculation... RENTERS insurance for earthquake is very inexpensive, I didn't factor in that you'd need OWNER (ie: structure) insurance.
The estimates for contracting work (seismic reinforcement) seem ludicrously low to me, but I don't have any basis for that opinion as I've not had to work with contractors here in the Bay Area.
I just find it hard to believe that doing major structural reinforcements to your home would be in the $20k range.
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[ 2.5 ms ] story [ 139 ms ] threadSome cities have made an effort to retrofit these buildings (Napa and Los Angeles come to mind) but there isn't a state driven effort to do so.
30 years later, no significant earthquake, and earthquake drills are nothing but a distant memory. I think humans are really terrible judges of what "long overdue" means, especially related to geological events.
Yes, at some point there will be an earthquake. Yes, some people will die. But overreacting and worrying about it when humans have no ability to predict it is worse. The best way is just do what we have been doing, which is increase building standards, have once-a-year drills, and stop trying to predict when disaster is going to strike, because humans can't.
If this happens with hurricanes, I can only imagine how the perception of saftety/danger gets skewed with earthquakes—which occur way less frequently than hurricanes.
If you're in a home, you might want to make sure that your supplies are more easily accessible from the perimeter of your structure in case enough damage is done that your home is not able to be entered. Ideally, a backyard shed or storage box would be the best place to store your supplies. If that's not available, in a garage near the rolling door or by a back door of the house.
If as much damage occurs to water and waste water infrastructure as they fear, and if your home becomes inaccessible, it might be prudent to make sure that you also have several changes of clothes and a pair of boots in your kit.
Basically, pretend that you're preparing for a week-long camping trip in the middle of nowhere and pack accordingly. Tent, sleeping bag, clothing, supplies, small solar panel to charge a phone, etc. It'll take a lot more space but it will make the (potential) experience a lot more tolerable.
The best data we have at the moment would be records of geologic events that have a strong correlation to earth quakes and seeing how they line up between the two different areas.
My gut tells me to expect, usually not co-incidence, but as they are part of the same larger system, possible co-incidence (and likely at a much more catastrophic level when something THAT LARGE does happen).
I've heard it said that the only way you can tell if an earthquake is a fore-shock or the main event is to wait. For example, I've always loved this visualization of the seismic events leading up to the major Japanese earthquake of 2011: https://www.youtube.com/watch?v=NSBjEvPH2j4 . See if you can identify the main quake when it happens. I bet you're wrong!
http://onlinelibrary.wiley.com/doi/10.1002/2013JB010635/epdf
And the 1857 and 1906 M7+ events on the San Andreas did not cause earthquakes in the Pacific Northwest.
However, dynamic triggering of earthquakes does happen:
http://lanl.gov/orgs/ees/ees11/geophysics/nonlinear/2005/Nat...
Note that this type of triggering (by passing seismic waves) is, in the absolute sense, really unlikely to specifically nucleate a M7+ earthquake; otherwise there would be chains of huge earthquakes every time there's a big earthquake in Tonga (which is all the time). However, the relative likelihood is increased substantially.
There is a lot of research on earthquake triggering (both 'static' and 'dynamic') much of which is publicly available on Google Scholar (or sci-hub...). Static (or 'Coulomb') triggering is the most physically comprehensible; dynamic triggering, where passing seismic waves cause new quakes, is statistically supported but hard to understand mechanistically. The basics of static triggering are that, if you think of the earth's upper crust as a compressed elastic (e.g. rubber, but far more rigid) sheet, when a tear in it happens (an earthquake) it changes the distribution of stress/forces in the elastic sheet. Some regions will be stressed more, particularly around the edges of the tear, and some will be stressed less. The areas that are stressed more by the new tear tend to have more earthquakes following the first one. This is largely a local (i.e. 10s of km) phenomenon.
The big paper on this is here: http://www.ipgp.fr/~king/Geoffrey_King/Publications_files/Ki...
If your last 100 "big ones" were 100 years apart (90 times) and 10,000 years apart (10 times), your median interval is 100 years and your average interval 1000, but if you're at 2000 years you might reasonably expect another 8,000 years before the next one...
This means there is elevated risk, but we can't say much more than that.
Should be tested somewhere, tho.
Heck it could even be fun. Make it a holiday, tell people the time its going to happen and let them ride it out. Personally, I'd be at a bar. :)
As for the actual method, nuclear bombs every few years for a large magnitude doesn't seem like it's mild enough.
We've seen that fracking often has the side effect of causing faults to get lubricated and slip more easily causing earthquakes.
Maybe research into the ideal chemical cocktail to most effectively lubricate and hook up injection stations along the length of the fault line, when there aren't aquifers in the nearby vicinity. Bonus for some kind of lubricant that degrades into non carcinogenic materials.
You wouldn't want to just start pumping fault lubricant into the system while it's so full of energy, but after the next "big" earthquake you could have a window where the pumping would trigger small size 3 or 4 earthquakes similar to aftershocks in perpetuity.
Not in my backyard.
I live about 3 miles from a large fault line, and am OK with it - my concern is that my family does not get crushed when/if the predicted big earthquake hits. As long as that is true, I do accept that I will have a lot of repair work to do, and will lose some objects. I am not going to live my life pouring money into preserving material goods, or preserving all of my home, when I can spend that same money rebuilding, when/if that day comes.
The issue is that our society at present does not single out life-critical operations and provide for them accordingly. The cost-benefit analysis has not been done.
http://www.newyorker.com/magazine/2015/07/20/the-really-big-... with 612 points w/ 275 comments: https://news.ycombinator.com/item?id=9878160
Although, I don't wish to downplay the risks of the San Andreas faultline.
It seems the west-coast should be investing a hell of a lot of money in preparation for this stuff. British Columbia, Washington, and Oregon included.
If I lived in a high risk area I would invest in a 'go' bag, a mountain bike, and a plan to get to high ground as quickly as possible. You'll have about 15 minutes after the earthquake before the wave hits. Cars will be useless in the traffic. The hardest part will be ignoring the initial destruction and focusing on getting out of the area.
https://www.ready.gov/earthquakes
For instance, 3 gallons of water isn't something you put in a go bag.
https://www.fema.gov/cascadia-rising-2016
I'm curious, not being from the area but planning to move to the west-coast, does it ever come up in local political discourse? And is it local common knowledge that it will happen eventually?
That said, after reading this thread I am going to invest in a supply kit..
The San Andreas fault, by comparison, runs right through the middle of densely populated areas of California. Minimal tsunami risk but much higher ground motion risk.
More details: http://www.vancouversun.com/This+Week+History+Huge+earthquak...
Google Map of Port Alberni & the Alberni Inlet (it's shockingly far inland): https://www.google.com/maps/place/Port+Alberni,+BC,+Canada/@...
I'm interested in moving to Victoria, Vancouver Island, BC, which is why it concerns me. I believe that would fall into the low-medium risk category:
> People living along the outer coast of Vancouver Island will have between 15 and 20 minutes to escape. Victoria can expect a tsunami wave of between two and four metres within 75 minutes.
http://globalnews.ca/news/1779057/boxing-day-size-quake-due-...
See page 16 for maps of predicted rise. You can compare that to an elevation map of the area, ie here with the contours turned on: https://maps.crd.bc.ca/Html5Viewer/?viewer=public. As you can see, in most areas the predicted rise of up to ~ 3 meters doesn't get you more than a few meters laterally away from the coastline. It will obviously still be a risk, but as long as you're not right at the beach it should be ok.
Seattle itself sits on the Seattle Fault (running from west of Bremerton, through Bainbridge Island, Alki Point, Beacon Hill, through Mercer Island to the east; subsidiary strands run through White Center and Issaquah), which is thought to have produced M7+ earthquakes in the past few thousand years [1]. These are shallow and surface-breaking and would be extremely destructive to the city. They are fairly infrequent (~5 in the past 16,000 years) but travel in packs [2].
Atkinson and Macias [3] estimate peak ground accelerations at ~2 m/s^2 (i.e., 20% gravity) in Seattle for a Cascadia event. Graves et al [4] (see Supplemental Fig 1) estimate PGA at about the same for most of LA given a M7.8 event on the San Andreas (which is the maximum estimated from paleoseismology and various other inferences). The SAF is 30 km from LA; the areas with much stronger local shaking are relatively sparsely populated desert regions. LA also has a lot of faults in the basin itself that are similar in size and slip rate to the Puget Lowland faults.
I think the recurrence intervals for the largest Cascadia events are very roughly 2-3 times those for the San Andreas (i.e. earthquakes are 1/2 to 1/3 less frequent).
[1]: http://geosphere.gsapubs.org/content/early/2014/06/24/GES009...
[2]: http://onlinelibrary.wiley.com/doi/10.1002/2013JB010635/epdf
[3]: http://www.openseismo.org/contributors/Lee/MoWorking_Backups...
[4]: http://onlinelibrary.wiley.com/doi/10.1029/2008GL035750/full
But, yes. The bigger problem is not the immediate damage from the quake. It's all the support infrastructure (water, power, roads etc) that will be knocked out, and may take a long time to restore.
Yes, such concentrated destruction will be quite dramatic, and will have serious economic and social consequences, but we should try to keep some perspective.
Now, if the Yellowstone Supervolcano erupted, that would be something.
In my car my bag has a laceration kit, water purifier straw and, hydration bladder. Also comfortable shoes for hiking and a hat. I can walk from anywhere in the Bay Area home in 2 days so that is the prep window.
Is earthquake insurance worth it?
What about retrofitting for earthquakes? I've read some pretty scary stuff that even retrofits done with permits don't have much consistency between them and no guarantees. Not even sure how to find a reputable retrofit contractor because I'm not sure how to judge the quality of their work since we haven't had a big one recently.
What should my priorities be for solving for all of this?
Every year they add a page or two to the contract, and we never even read the policy.
I don't know why a state like California lets them get away with covering so little?
You know why I don't know our Insurance Commissioner's name off hand--because he doesn't do anything.
As far as I could tell, the most important components are to make sure your sill plates are firmly attached to the foundation (with big washers on the bolts going through the sill plates or the Simpson UFP or some other plate), shear walls, and post caps. I talked to a Simpson field engineer (they actually answer the phone) that essentially confirmed this.
http://www.strongtie.com/resources/literature/seismic-retrof...
http://www.earthquakecountry.org/step1/gassafety.html
Any contracting service is incredibly contractor-dependant (as you've surmised).
Single story home? Really look at making your own go-bag. Take a survival course, not because you'll be in the woods picking berries, but because you'll learn transferable ways of looking at the (natural?) resources around you and how you can use them to survive or thrive.
https://www.verlocal.com/search?&page=1&keyword=survival
Have a go-bag in your car and by your bed (that include emergency rations and bottles / jugs of water, clean underwear, a toothbrush, etc). I bought a few cheap pop-up tents when they were on sale at woot.com. You can bet I'll be happier during a disruption of services than my neighbors who don't have even a basic set of supplies put together.
My theory is: Odds of a severe earthquake in the next 50 years are let's say 1/50. Do you spend $100k+ on earthquake retrofit, or spend $20k on insurance that'll let you rebuild? (my numbers are completely made up, btw).
Well, you have to purchase earthquake insurance anyway, and a single-family home is "less" dangerous than a multi-story home. Look at pictures of wood-frame earthquake damage and figure out what your state of mind would be after you run outside and your house ends up like this:
https://www.google.com/search?q=wood+frame+earthquake+damage...
Figure out your go-bag situation, learn how to use it, take a survival course, keep lots of water handy, buy a tent, and then only worry about it in order to keep your supplies and skills fresh.
Since you have a house, also run a 55 gallon drum / trash can setup out in the back yard.
https://www.google.com/search?q=trash+can+survival
Hope that helps!
[1] http://www.seismic.ca.gov/pub/CSSC_2005-01_HOG.pdf
The estimates for contracting work (seismic reinforcement) seem ludicrously low to me, but I don't have any basis for that opinion as I've not had to work with contractors here in the Bay Area.
I just find it hard to believe that doing major structural reinforcements to your home would be in the $20k range.