Forgot your password?
typodupeerror
Science

An Early Warning System For Earthquakes 147

Posted by kdawson
from the whole-lotta-shakin' dept.
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."
This discussion has been archived. No new comments can be posted.

An Early Warning System For Earthquakes

Comments Filter:
  • by solafide (845228) on Tuesday December 05, 2006 @09:09PM (#17122650) Homepage
    It takes 20 seconds for it to travel 40 miles? How much power has that secondary wave lost in those 40 miles? Wouldn't it take one really powerful earthquake for you to need to take cover 40 miles from the epicenter?

    (I'm not an expert on earthquakes, but 40 miles seems like a long way for the earthquake to travel.)

    • by Harmonious Botch (921977) * on Tuesday December 05, 2006 @09:14PM (#17122706) Homepage Journal
      "Wouldn't it take one really powerful earthquake for you to need to take cover 40 miles from the epicenter?"

      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.
      • by geekoid (135745)
        If by no, you mean yes your correct.

        Depends on location, soil, etc.. for example, if you live at the end of the fault, you will experience a much stronger event.

      • by sfjoe (470510) on Tuesday December 05, 2006 @09:32PM (#17122922)

        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.
        • by davidsyes (765062) on Wednesday December 06, 2006 @12:41AM (#17124642) Homepage Journal
          I was lucky that day. I had only minutes before left Grand View (Chinese) Restaurant (they changed names to Fortune after the quake) with a few cartons of food and couldn't decide whether to go straight back to Milpitas or to dart over to Embarcadero and shoot a few pictures.

          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...
      • by brian1078 (230523) on Tuesday December 05, 2006 @10:08PM (#17123262) Homepage
        The epicenter of the 1989 Loma Prieta earthquake was in the Santa Cruz mountains, about 60 miles south of San Francisco and Oakland. Some of the worst damage was in these areas. The "Cypress Structure" of the I-880 freeway collapsed, as did a portion of the Bay Bridge. In the town, another 20 miles north of Oakland, I lived in at the time there was considerable damage to some older structures as well as to personal property.

        I would have been happy to have the 15 seconds notice.
        • The peak energy of quakes decreases in frequency (dispersion) as it goes off into the distance. Buildings and mud layers have resonant frequencies which can effective triple the force of the wave as it passes by. The Loma Prieta "sweet spot" was not close-in in Silicon Valley mudflats, but about twice that distance in Oakland and San Francisco Marina.
      • Re: (Score:3, Informative)

        by thebdj (768618)
        Our house is about 20 miles from epicenter of the 1994 Northridge quake

        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.
      • by lpq (583377)
        You are uninformed.

        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.
    • by robzon (981455)
      actually, they can go as far as 60 miles from the epicenter. cheers.
    • Re: (Score:2, Informative)

      by MaXiMiUS (923393)
      According to http://home.att.net/~srschmitt/script_earthquake.h tml [att.net] -- 1a 100km damage zone is common for earthquakes around 6.1-6.9 on the Richter scale, so 40 miles is a reasonable damage zone. I have no idea on the 20 seconds/40 miles measurement however.
    • by Beryllium Sphere(tm) (193358) on Tuesday December 05, 2006 @09:16PM (#17122726) Homepage Journal
      1985, Mexico City, buildings collapsed when the center of the earthquake was 400 km away. That one was unusual but it shows what's possible.

      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: (Score:3, Informative)

      by mla_anderson (578539)

      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.

    • Re: (Score:2, Informative)

      by drpimp (900837)
      It really all depends on what types of crust your epicenter and surrounding areas are, along with depth of the epicenter. Crust content surrounding an epicenter can also increase or decrease wave displacement, direction, and force. Giving a maximum distance for initial or secondary waves, can only be estimated based on the recorded seismic history of a given area and the surrounding crust, any estimate are in fact only that. Living in Southern Cali myself, I can tell you, I have felt quakes for 60+ miles, o
    • by eh2o (471262)
      I suppose that the falloff is not uniform because the wavefronts don't quite propagate circularly from the epicenter, but rather from a distribution over the faults (who's mode is the epicenter).

  • Oblig.. (Score:1, Funny)

    by Kisil (900936)
    Shaking things up in the news today?
  • Safety valves? (Score:4, Interesting)

    by EaglemanBSA (950534) on Tuesday December 05, 2006 @09:13PM (#17122692)
    There would still be gas in the main lines, how would shutting a safety valve keep a broken pipe from leaking gas already in it?
    • Re: (Score:3, Informative)

      by frosty_tsm (933163)
      Possibly it would prevent the continued flow of gas to the pipe. Some would still leak, but either the gas would burn out quickly or dissipate before it's ignited.
      • Re: (Score:3, Informative)

        by Jeff DeMaagd (2015)
        I think this damage mitigation is the basic idea. It's almost impossible to prevent a rupture, but should it rupture, you don't want gas to continually push through it. Gas often dissipates very quickly, but if it has a constant supply and happen to have a spark nearby, then it's asking for trouble that could have been avoided if you had shut-off valves.
    • Re: (Score:2, Interesting)

      by TransEurope (889206)
      Great idea. Another thing is to automatically
      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.
      • Would they be able to do this at the distribution center? Like shut grids of power off, and shut valves that supply that area. Seems kinda feasible to me unless its jut one big pipe that goes to every house in the area of all of California. Then again I don't know about that so I could be wrong.
      • Another thing is to automatically 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?

        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

    • by kryten_nl (863119)
      It doesn't. But closing valves, while everything is still operational, might make the length of pipe, that is affected, a lot smaller.
    • Actually, there's a bigger problem: If you turn off the gas, everyone's pilot lights go out. When it's turned back on, you'll get a lot of fires from people failing to relight them, or doing it wrong. Also, you're still going to have the leaks in the system to deal with, although under better circumstances.

      I'd suspect turning the gas off might make things worse, not better.
      • by nahdude812 (88157) *
        Most modern pilot lights use a heated spring to hold the gas flow open. If gas is lost, it will cool and close itself. This is why when starting it from cold, you have to hold a manual release for 8-10 seconds while the pilot warms up.
  • Radon (Score:2, Interesting)

    by APE992 (676540)
    My geology professor has gone over it again and again, Radon could potentially be an early warning system in some cases. Naturally the stuff leaks out of the ground, before an earthquake more of it is supposed to come out due to the shifting of the ground up to the earthquake. This could be months, days, minutes that this is detectable. Someone with a better understanding please correct anything and add to this.
    • Re: (Score:3, Insightful)

      by The_Wilschon (782534)
      Gosh, I did a seventh grade research paper ages ago on predicting earthquakes. I did mention radon... However, the conclusion of my paper was that earthquakes really couldn't be reliably predicted, so I suppose that some source I had said that you really couldn't effectively use radon as a good predictor, but I can't remember why exactly.

      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
    • The USGS started Radon measurements right after the Chinese and Russians claimed some encouraging results in the early 1970s. The results have been inconclusive. There have been a dozen sizeable quakes in the San Andreas area where the USGS has its sensors- all inconclusive.
      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)

    by Anonymous Coward on Tuesday December 05, 2006 @09:14PM (#17122704)
    What do earthquakes need to be warned early about?
  • Sigh (Score:5, Informative)

    by geekoid (135745) <dadinportlandNO@SPAMyahoo.com> on Tuesday December 05, 2006 @09:19PM (#17122764) Homepage Journal
    "... brace yourself in a doorframe ..."

    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.

    • Re: (Score:1, Informative)

      by Anonymous Coward
      I don't know about where you live, but in my country, doors aren't just holes in the wall with a bit of wood slapped round them, they usually have a concrete lintel (sp?) over the top of them to distribute the weight of everything above them evenly, so a doorway would provide much better protection than standing in the middle of a room.
      • they usually have a concrete lintel (sp?) over the top of them to distribute the weight of everything above them evenly, so a doorway would provide much better protection than standing in the middle of a room.

        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

        • Re: (Score:1, Informative)

          by Anonymous Coward
          I have seen more 2x8s or 10s (usually short pieces from the scrap pile after the sills or rafters are put in) used as the headers in doorways. And being on edge, then over the studs, that makes doorways much stronger than the rest of the wall, even though the gap is larger. I don't think just a 2x4 slapped sideways on top flies many places any more for code, geez, not for decdes maybe. I know some places have almost no code, but just simple framing tends to be almost universal.
        • by JanneM (7445)
          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

          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)

        by Beryllium Sphere(tm) (193358) on Tuesday December 05, 2006 @09:43PM (#17123042) Homepage Journal
        There's still a door swinging in it. Depending on which way you're facing, you could get your fingers pinched in the hinges and mangled, or slammed into by a closing door and mangled.

        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.
        • If things start shaking, I follow the advice on my safety pamphlet: go straight to the kitchen (room in the house with the least things to fall from above in my circumstance), get under the table, and stay there until the shaking stops plus a few minutes to ride out the aftershock and any settling of objects in the cabinets. Unfortunately the earthquake always seems to happen when I've in the bath or otherwise naked. I remember being scared out of my wits during my first earthquake (grew up in Illinois) a
    • "... brace yourself in a doorframe ..."

      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
    • ...or you could and up being a crippled stud.
  • Not enough time (Score:3, Interesting)

    by El Cubano (631386) <roberto@conDALInexer.com minus painter> on Tuesday December 05, 2006 @09:26PM (#17122838) Homepage

    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)

      by Pyromage (19360) on Tuesday December 05, 2006 @10:41PM (#17123488) Homepage
      Of course more time would be better. However, nearly everything important can be done in 15 seconds. The really critical things. Like getting the generators at the hospital up to keep the ICU running. Closing gas mains. Taking the scapel out of the guys brain during surgery.

      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.
    • The IEEE article is about what amounts to a strain gauge, which (if confirmed) tells you that something is about to crack but doesn't tell you how far and how widely the fault is going to unload itself. There's some reason to suspect that when an earthquake starts it doesn't "know" how big it's going to be.

      Once the p-wave hits, though, you know what kind of ground acceleration to expect.
    • Re: (Score:2, Interesting)

      by Sibko (1036168)

      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

    • Consider the implications if we told LA that there would probably be an earthquake there sometime within the next 2-3 days. The ensuing panic and pandemonium would cause more harm than the quake.
  • 15 seconds (Score:2, Funny)

    by rolyatknarf (973068) *
    is barely enough time to evacuate your bowels - let alone prepare for a large quake.
    • by robzon (981455)
      But it's probably enough to save many lives. Sometimes 15 seconds is all it takes to significantly increase your chance of survival.
      • "Sometimes 15 seconds is all it takes to significantly increase your chance of survival."

        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.
        • So you do drills. You practice moving without panic when an alarm goes off. Maybe you were terrified when your building started shaking, but when was the last time that ringing bells paralysed you with fear?
          • by ewl1217 (922107)
            Ringing bells alone won't paralyze you with fear (at least not normal people...), but when they mean that there's an earthquake and that the building you're in might collapse on you then they sure could.
    • Ahem. I, for one, don't want to shit myself in the middle of a massive earthquake, so maybe that's what the warning system should be used for: Avoid embarrassing smelly aftershocks in your pants!
    • Only 15 seconds? You youngsters!
  • by Hays (409837) on Tuesday December 05, 2006 @09:34PM (#17122952)
    I thought the high speed trains in Japan would stop in the event of an earthquake (before the earthquake actually hit them), http://en.wikipedia.org/wiki/Shinkansen [wikipedia.org]

    "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.
  • by Bananatree3 (872975) on Tuesday December 05, 2006 @09:35PM (#17122970)
    ElarmS [elarms.org].
  • by djupedal (584558)
    ..of crap. 15 seconds my ass.


    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 :)
  • just huge strobes-- don't get on the overpass-- and the underpass...

    *** 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)

    by budgenator (254554) on Tuesday December 05, 2006 @09:46PM (#17123068) Journal
    While the article is quite light on details, much work has been done in this area, by groups such as ElarmS [elarms.org] in California, if your interested in the methodology take a look at Allen's [elarms.org] paper "Rapid magnitude determination for earthquake early warning (a 7 pg. PDF) which is reasonable understandable by lay persons if you skip through the math, yet still informative for people in the field.
  • Here in Greece we constantly suffer from nasty earthquakes. A company [egelados.gr] led by a well-known seismologist here sells products like the one mentioned. It also sells metallic boxes where you can hide inside during a quake. Too bad I haven't got any of these products, they could save my life one day. However, I believe there is no better protection against quakes than living in a flexible wooden house that 'moves' together with the seismic waves as they pass, instead of these stupid concrete boxes that break apar
    • Re: (Score:3, Insightful)

      by The MAZZTer (911996)
      Ah but which building designs would fare better in a hurricane or tornado? Flooding? We have more than just earthquakes for natural disasters...
      • Structurally integrated ones help with all those.

        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.
    • by JanneM (7445)
      However, I believe there is no better protection against quakes than living in a flexible wooden house that 'moves' together with the seismic waves as they pass, instead of these stupid concrete boxes that break apart because they tend to resist against the seismic waves (and we all know nothing artificial can resist natural forces for too long, except for those things that are inspired by nature itself, like wooden houses).

      Most deaths in Kobe were in "flexible wooden houses", while your "stupid concrete bo
    • >a flexible wooden house that 'moves' together with the seismic waves

      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
    • by TheLink (130905)
      Well any Ancient Greek temple that had problems would not be standing anymore, people would just clear the rubble and build something else over it ;).

      Survival of the fittest.
  • Importantly, while 15 seconds is probably not enough time for something like a high speed train to stop, I'd much rather be travelling at 50mph rather than 200mph when the earthquake hits ;-)
    • by Firehed (942385)
      I'd rather be traveling 200mph... as long as it's *away* from the quake. Or, better yet, nowhere near the thing at all.
      • by TheLink (130905)
        So you'd rather be 15 seconds away (0.8 miles?) and still travelling at 200mph on a track that's now broken?
  • I thought I read about this somewhere, or maybe it just came up in conversation, but I can't find the reference...

    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
  • Moo (Score:2, Funny)

    by Chacham (981)
    This whole idea sounds pretty shaky.
  • This is somewhat like a project I did in my undergrad software engineering course. We spent the whole semester in a mock scenario role playing the software development cycle. We did everything up to implementation. Held requirements meetings with the Government of 'Claremount' - a fictional country prone to earthquakes and tsunamis (and this was before the big one that got all the attention), analysis of their needs, design of a detection grid and alert systems. Created UML diagrams for a java implementati
  • reminds me of the tornado warnings in middle america/central plains.
    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?
    • reminds me of the tornado warnings in middle america/central plains. 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.

      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

  • http://bssa.geoscienceworld.org/cgi/content/abstr a ct/95/2/708 [geoscienceworld.org]

    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.
  • From TFA:

    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
    • by bcattwoo (737354)
      Actually, it looks like they used some kind of new math in the second sentence. If the S wave travels at 3.5 km/s, then it should travel 35 km in 10 s and take 17 s to reach that city 60 km away. The difference in arrival time of the P and S waves at the city would be 7 seconds, which means this method of detection would be a ~100% increase in warning time.
    • You can shutdown the subways, shut off refinery valves, park computer disk arms, and walk to a safer location.
  • You may be able to leave a two floor residence in 15 seconds - if you are prepared to start running every time of day or night. As it is, you probably wouldn't even realize what is happening before the wave hits. In highrise office buildings, there is no chance you can get out of elevator in time.
  • "An Early Warning System For Earthquakes"

    Um ... shouldn't WE be the ones being warned ?!?

  • I can still remember the Great Dudley Earthquake of 2002, I don't think there would be any point in installing such a monitoring system in the UK but I did briefly consider moving the bookshelves and couple of hundred hard back books from above my head.

    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 to kiss your ass goodbye. :)
  • I worked in a scary manufacturing/research environment for a while: we had *lots* of big fluorine lasers. There were two alarms: fire, and fluorine. When the fire alarm went off, people sat around for a moment, looked at each other, waggled eyebrows, looked around some more, then moseyed over to one of the windows on the manufacturing floor to see if there were visible flames, and then slowly, reluctantly, walked over to the door and went outside. When the fluorine alarm went off, people dropped everythi
  • One serious problem with tsunami-size quakes, M7.5 and larger, is to accurately measure the magnitude of the large quake. Regular seismographs saturate at high magnitudes- that means that an 8 looks just like an 8.5 looks just like a 9 for conventional single-station magnitude calculations. There is a more accurate calculation called moment-magnitude, but that requires collecting data from at least a hemisphere of stations, preferrably a full global. That requires an hour, half an hour for the wave to
  • So the rescue works can go in the right direction. Cant depend on media to all be working then.

    The southern california early alert system (for organizations only) tries to compute and notify location ASAP.
  • Just using a simple radio transmitters connected to pinball machine tilt switches, and place them in a grid one every 10 miles or so, you would be able to get a very advanced warning.

    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

I don't want to achieve immortality through my work. I want to achieve immortality through not dying. -- Woody Allen

Working...