An Early Warning System For Earthquakes 147
Iphtashu Fitz writes "Would 15 seconds be enough warning time to prepare for an earthquake? It certainly wouldn't be long enough to evacuate from where you live, but it may be just long enough to get out of a building or brace yourself in a doorframe or under a solid desk. Italian scientists may have discovered a way to measure the initial shockwave of an earthquake two seconds after it starts, and from it predict the extent of the destructive secondary wave that will follow. It typically takes twenty seconds for the secondary wave to spread 40 miles, so sensors that can transmit warnings at the speed of light may provide just enough warning before a major quake for people to brace themselves. Even more importantly, such a warning could allow for utilities like gas companies to close safety valves, preventing potential fires or explosions in the aftermath of the quake."
One powerful earthquake? (Score:4, Interesting)
(I'm not an expert on earthquakes, but 40 miles seems like a long way for the earthquake to travel.)
Re:One powerful earthquake? (Score:4, Informative)
Yes.
Our house is about 20 miles from epicenter of the 1994 Northridge quake, the most costly quake ever recorded ( California housing is expensive ), and it was not damaged at all. I don't recall Oakland or Berkeley suffering much from the SF earthquake in the 90s, and they are less than 40 miles away.
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Depends on location, soil, etc.. for example, if you live at the end of the fault, you will experience a much stronger event.
Re:One powerful earthquake? (Score:5, Informative)
The collapsed Cyprus freeway was in Oakland. It's believed that earthquake waves travel horizontally through the crust and can also be reflected off of harder layers further down. If the original wave and the reflected wave harmonize they can be extremely destructive even many miles from the epicenter.
Re:One powerful earthquake? (Score:4, Interesting)
By the time I'd decided it wouldn't be good to get the food late to some people I told about the restaurant, when I decided to head on south, I was barely out of Oakland, somewhere south of Cypress on 880 because. Had I gone to SF, I'd have been SOMEwhere on the Cypress. It's possible I could have also been somewhere before the fallen deck section, but that all could have depended on how many people on the Cypress would have been in my way (back then I might have wanted to speed, might have just relaxed and slipped in and cranked up my Depeche Mode cassettes, (but instead I kept the KGO talk on), blah blah blah...) and I am SURE I'd have probably died that day had I not just taken the food straight to my friend.
I think I was barely north of the Marina shopping outlet when my steering started acting up. I couldn't believe my barely 1 year old car was acting up. Then the radio went out. There wasn't too much traffic in that section, so my eyes fixated partly on the road and partly on the trees. When I saw them swaying, I knew my car was OK, but the radio was hissing. Only a few weeks earlier IIRC, KGO's antenna near the Dumbarton Bridge went out and needed repairs, so I thought they were having problems. I tuned to other stations only to hear noise and mostly silence, but sporadic bits mentioned major earthquake.
Fortunately, the roads don't open up like they do in hollywierd flicks. Fortunately it wasn't in the thick of commuter traffic, or there might have been collisions all up and down the freeway for dozens of miles if anyone freaked and lost control of the car. I was fortunate that day...
Re:One powerful earthquake? (Score:4, Informative)
I would have been happy to have the 15 seconds notice.
"sweet spot" at 60 miles (Score:2)
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Then apparently you were lucky [wikipedia.org].
BTW, that 1990s quake, was 1989. And damage was severe upwards of 50 miles away, if you check here. [wikipedia.org]
BTW, its epicenter was closer to Santa Cruz, so it did a lot of damage considering it travelled nearly 50+ miles to reach the bay.
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From wikipedia:
magnitude 6-6.9 quakes can destructive in areas up to 100 miles
across. For 8-8.0 magnitude quakes, serious damage can cover areas several hundred miles across. For a magnitude 9 or greater, we are talking areas several THOUSAND miles across.
So...yeah, a 15 second warning per 40 miles would be very useful. As for your house being undamaged -- consider yourself lucky.
As for some SF earthquake in the 90's in the Bay Area -- I don't recall any quakes of any large magnitude.
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Re:One powerful earthquake? (Score:5, Interesting)
The other thing you can do with 10-20 seconds of warning is apply emergency brakes on the bullet trains, which I believe Japan has arranged to do.
Re:One powerful earthquake? (Score:4, Insightful)
No, it shows what Mexican building codes are like.
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Good building codes wouldn't have been enough.
Not True (Score:1)
Solid engineering seemed to save this one. From University of Illinois professor Nathan Newmark, nonetheless.
don't forget the bribes (Score:2)
Pay the inspector, and you can live in a house of bricks held together with dried cow dung.
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Cinco de Mayo [wikipedia.org] probably has that kind of blast radius as far as knocking over buildings in Mexico.
why apply brakes? (Score:2)
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The epicenter of the Kashmir earthquake (2005, Pakistan & India, 7.6) was 62 miles (100km) away from Islamabad and yet it knocked an apartment building down.
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Oblig.. (Score:1, Funny)
Safety valves? (Score:4, Interesting)
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interrupt the electricity in the buildings to prevent
fires caused by short-circuits. But what would it cost
to equip all houses in San Francisco (or any big or medium
sized city) with such systems? Maybe billions of dollars.
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Circuit Interruption, etc. (Score:2)
If you really wanted to do that, you'd do it at the substation level. But I doubt you would. Substations already have circuit interrupting switchgear, houses have fuses and breakers, outlets in particularly hazardous locations have GFIs. Electricity won't leak out and start
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I'd suspect turning the gas off might make things worse, not better.
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Radon (Score:2, Interesting)
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Some speculation: Perhaps false positives were an issue. After all, shutting a city down for an earthquake is an expensive proposition (just in lost time if nothing el
30 years of studies inconclusive (Score:2)
Besides radon is a slow signal. In the few promising results, the radon starts increasing weeks before an event, but with no clear signal pointing to the day or hour.
Huh? (Score:5, Funny)
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Sigh (Score:5, Informative)
this is a myth. The only thing this acomplishes is broken fingers.
It stems from an observation from a red cross worker after a earthquake in mexico.(I think 1950ish.)
That archtecture of the entrance way was an adobe arch. Arches are very strong, as opposed wooden square door frames.
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not everyone is so fortunate. (Score:2)
There are no hard-fast rules here. In many simple-wood frame houses here in the USA doorframes are usually a couple of 2x4's nailed together. However that is not to say every doorframe is that way. A bunker doorframe would do nicely, however not everyone has such a thing
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If you live in an area where significant earthquakes are probable you have laws restricting how you are allowed to build; you won't have doorframes made from a couple of flimsy boards.
In Kobe most of the damage and almost all of the deaths were in old buildings erected before
Re:Sigh (Score:5, Informative)
Drop, cover, and hold is what the Red Cross is teaching, after considerable research.
First-world building are unlikely to collapse but you don't want to be hit by falling chunks of ceiling. Get under something like a table ("drop and cover") that will intercept some debris before it hits you.
The table will likely start walking across the room as everything moves up and down and sideways. Keep a grip on a leg of the table or whatever and "hold" so that it doesn't walk away from you.
Doesn't have to be a table, and improvising is good. At the grocery store you could use a shopping cart, for example.
Japanese government advises the same (Score:2)
Loma Prieta deaths from this. (Score:3, Interesting)
this is a myth. The only thing this acomplishes is broken fingers.
A very dangerous myth, too. Most of the deaths in Loma Prieta may have resulted from this myth.
There were 57 deaths attributed directly to the earthquake, and 42 of them were in the Cypress Street Viaduct collapse.
At the start of the earthquake, the drivers stopped. Because of the myth, most of them tried to stop under the arches. When the strucutre collapsed, the arches came all the way down to the p
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They had archways under the roadway at each set of supporting legs.
Drivers aware of the "get in a door because it has a frame to protect you" story interpreted these as equivalent and selectively stopped in the worst possible place.
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broken fingers (Score:3, Funny)
Not enough time (Score:3, Interesting)
Would 15 seconds be enough warning time to prepare for an earthquake?
Nope. But a few hours to a few days [ieee.org] would be lots better.
Re:Not enough time (Score:4, Insightful)
You can't drive home from the grocery store and strap yourself into bed in 15 seconds, but you can do a lot of really really important things in that time.
Might not be as good (Score:2)
Once the p-wave hits, though, you know what kind of ground acceleration to expect.
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Would 15 seconds be enough warning time to prepare for an earthquake?
Yes, it would.
I worked at a shipping warehouse, and I can tell you that even 5 seconds of warning prior to an earthquake could save the lives of workers. The goods are stacked up 4-5 stories high, and each crate easily weighs half a ton or more. It wouldn't take much shaking to knock the top ones down and crush people.
Considering the size of the building I worked at, the only real options available would be to either get out of the isle as fucking fast as you could, or to get under the girders supp
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15 seconds (Score:2, Funny)
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Re:15 seconds - not much (Score:1)
You are right but only in some instances. I was at work in a factory in Emeryville, CA in 1989 during the Loma Prieta Earthquake. I was a mile or so from the Cypress Street Viaduct when it collapsed. 15 seconds in that case meant nothing at all. All we could do was hold on and hope the building didn't fall in on us. When you are really terrified it's nearly impossible to do much in 15 seconds.
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Doesn't japan have something like this? (Score:4, Interesting)
"In the event of an earthquake, an earthquake detection system can bring the train to a stop very quickly"
Anyway, the idea of a broadcast system to warn of an earthquake is pretty obvious, the engineering task of doing it right without false positives is pretty difficult I bet.
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http://www.hinet.bosai.go.jp/AQUA/aqua_eq.php [bosai.go.jp] shows the location of any recent earthquake.
http://www.hinet.bosai.go.jp/AQUA/max_amp.php [bosai.go.jp] shows all earthquakes, as animated maps. Check out 2006/11/15 20:15:58 for a very interesting animation.
http://www.hinet.bosai.go.jp/ [bosai.go.jp] is the main page.
In terms of real time alerts, if the earthquake web site's down, it means there's been an earthquake.
Yes! And already implemented! (Score:2)
Since March 30 of this year, Japan's Meteorological Agency [jma.go.jp] has been operating a nationwide system [kishou.go.jp] [Japanese] to measure P-waves and estimate the earthquake's strength before the S-waves hit. While they say it's still experimental, it's been brought up in the news several times, and has in fact predicted [kishou.go.jp] [Japanese--partial list only] several significant earthquakes successfully, though it's put out a few false alarms as well. (One false alarm is listed as having been caused by a lightning strike, and they
UC Berkley has a very similar early warning system (Score:3, Informative)
Load (Score:2)
When you've lived in San Francisco and/or Tokyo as I have, you move without thinking.
And if that means climbing over you to get to the exit, then buddy you better duck, 'cause I'm coming thru
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Bookmarks -> Entertainment -> Recent Earthquakes - Map for SanFrancisco" [usgs.gov]
how about just overpasses (Score:2)
*** HALT MFKR ***
or enter chasm
15 seconds enough to keep you from becoming a autobutter sandwich or a car contained base jumper?
Its being done now, (Score:3, Informative)
Already sold in Greece (Score:2)
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Seismic retrofitting, among other things, straps together the different stories of a building and strengthens the connection to the foundation, putting "shear walls" over studs, and generally making the structure more of a unit so that an earthquake can't play divide and conquer (search term: "soft story").
Hurricane resistance requires the same kind of thinking: tie the roof to the rest of the structure.
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Most deaths in Kobe were in "flexible wooden houses", while your "stupid concrete bo
Building engineering (Score:2)
Unless it slides off the foundation. You need some rigidity.
Wood can be good, steel can be good, even reinforced concrete can be good. The thing you need that no building provides enough of is "damping", energy dissipation, what a shock absorber does. Imagine a car with no springs, then imagine a car with only springs, and you've got two lousy rides. The architectural equivalent of a shock absorber is a material which drags its feet whe
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Survival of the fittest.
High speed transport (Score:2)
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Hard drive shock sensors? (Score:2)
Anyway, the idea is this: If you have a laptop with a jolt/bump sensor (I have an IBM at work that does this, I'm sure others do to), you voluntarily run some software that knows where your laptop is by its IP address and when a shock hits it, it sends that info to a central server. Normally, it will just be noise... random shocks and drops coming from all over... but when all of a sudden the
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Moo (Score:2, Funny)
just like . . . (Score:1)
warning (Score:1)
by the time the Hams radioed that one was on the ground, it was confirmed, and a signal was sent to ativate the system, the tornados were often over.
as my dad used to say, survivors will be notified.
we just listened to the hams our selves.
will there be a consumer version of this?
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Most tornados are spotted by radar now. Much more effective than human spotters, particularly at night. We've got multiple zones per county in some areas, so only sirens in a tornado's path are sounded. There's plenty of warning of tornados here, usually.p> One disadvantage of the auto
Already been done in Japan (Score:2)
I actually had the honour of proof-reading this paper before it was published. One of the authors is my wife's uncle.
This system is already in place and working today. It is based around a network of buried sensors that allow the accurate location of the epicenter within just a few seconds. The system is used to shut down high-speed trains, etc, before the damage-causing vibrations arrive.
All this for a 6.2% increase in warning time? (Score:2)
Primary waves travel around six kilometers [four miles] per second, covering around 60 kilometers [40 miles] in 10 seconds. Secondary, or S, waves, which are usually more destructive, travel more slowly, around 3.5 kilometers [2.2 miles] per second, covering only around 17 kilometers [11 miles] in 10 seconds. Therefore, a city located around 60 kilometers [40 miles] from an epicenter would have around 15 seconds of lead time to prepare for an earthquake's impact, the time difference between the arr
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10 second is an eternity (Score:2)
Useless (Score:2)
warn them (Score:2)
Um ... shouldn't WE be the ones being warned ?!?
The Great Dudley Quake Of 2002 (Score:2)
15 seconds is obviously maximum amount of warning this system can provide so in practice even with the system most people would get much less than this. Although in theory people can take some appropriate action in 15 seconds to mitigate the earthquakes effec
Just enough time... (Score:2)
fifteen seconds is a long time (Score:2)
very large magnitudes a problem (Score:2)
fast location important too (Score:2)
The southern california early alert system (for organizations only) tries to compute and notify location ASAP.
It's possible to have up to a 3 minute warning. (Score:2)
You'd want to agrigate the warning system into one or more centralized alert systems so that they can wait for multiple even triggers before sounding an alert.
Just as the 15 second warning system describe in the parent article here, the further from the epicenter the more warning you have but with this your adv