Want to read Slashdot from your mobile device? Point it at m.slashdot.org and keep reading!

 


Forgot your password?
Close
typodupeerror
×
Science

"Slow" Earthquakes May Help Predict Major Quakes 107

Posted by Hemos from the rocking-and-rolling dept.
Iphtashu Fitz writes "Think all earthquakes last only seconds or minutes? Think again! Scientists at the University of Washington are measuring a "slow" earthquake some 12 to 25 miles underground that could last as long as a month. Along with the UW scientists, seismologists at the Geological Survey of Canada and Central Washington University have documented at least nine previous so-called slow earthquakes going back to 1992. They seem to occur every 14 months or so, the last one occuring in February and March of last year. These earthquakes, also known as slow-slip earthqakes, can release as much energy as a magnitude 6.8 earthquake but because it's released over such a long period of time nobody on the surface even notices it. One key question the scientists are trying to answer is whether these slow earthquakes add to or relieve stress in the tectonic plates, which could ultimately help to predict major earthqakes."
This discussion has been archived. No new comments can be posted.

"Slow" Earthquakes May Help Predict Major Quakes More

"Slow" Earthquakes May Help Predict Major Quakes

Comments Filter:

  • can release as much energy (Score:5, Interesting)

    by Visaris ( 553352 ) on Monday May 24, 2004 @01:06PM (#9239224) Journal
    These earthquakes, also known as slow-slip earthqakes, can release as much energy as a magnitude 6.8

    Does this not imply stress is being released?
    • I'm confused about the same thing. Can someone explain how an earthquake can possibly add stress to the tectonic plates?
      • I thought about this as well and the common sense answer seems to be that because these slow slips are happening deep underground the surface isn't keeping up. So maybe when the stretch between the surface that hasn't moved and the underground that's been creeping along gets too great then the surface cuts loose with a big one-time quake. Anyway, that's the best I can come up with for why it could add to surface earthquakes.

      • Re:can release as much energy (Score:4, Interesting)

        by cluckshot ( 658931 ) on Monday May 24, 2004 @03:29PM (#9240537)

        I would suggest that what they are measuring is the train speeding up leaving the station. Then it runs into something...

        I recently did some serious looking into the issue of tides etc and found that the trigger event for most earthquakes is a Tidal Flux. Remember there are Land Tides, Atmospheric Tides as well as Ocean Tides. Land Tides are quite significant. The Flux is an interaction between the Sun, Moon and the Earth. Most earthquakes occur when the moon is very close and is at 90, 45, 22.5 degrees etc to the sun. The flux is stronger on the closer to right angles and where the moon/sun aggrigate is accelerating the land. This I would assume is both cause and trigger but it is not fully known.

        Other research shows that Full Moons tend to produce more tidal stress than new moons due to Gravity shielding.

        There is a lot of research going on regards the prediction of Earthquakes and to represent the most successful to date tech is that like a big board that is being cracked by a hydrolic press, it begins to snap an pop a little then suddenly it fails all together. By listening for the pattern of small pops the big pop becomes more and more certain.

        The Tidal techtonic forces have been observed on the moons of Jupiter and Saturn. This is related to the charging up of energy.

        UFO type sightings often are precursors to Earthquakes. This is because the earth emits certain sub atomic radiation that appears as solid shiny balls/disks or fast moving ones. This appears to be related to the energy holding the structure of matter together.

        • UFO type sightings often are precursors to Earthquakes. This is because the earth emits certain sub atomic radiation that appears as solid shiny balls/disks or fast moving ones. This appears to be related to the energy holding the structure of matter together.

          You make quite a few interesting points in your post. Do you have any links / backup documentation available to support some of your statements?

        • UFO type sightings often are precursors to Earthquakes. This is because the earth emits certain sub atomic radiation that appears as solid shiny balls/disks or fast moving ones. This appears to be related to the energy holding the structure of matter together.

          Damn, you almost had me, but that line was a dead givaway.

          Keep up the good work.

    • Re:can release as much energy (Score:2, Interesting)

      by Anonymous Coward
      Stress relief in one place can increase the stress somewhere else. Perhaps that's what they mean. So yes, stress would be relieved by the energy release of the slow-slip earthquake, but this may mean that remaining stresses are now more concentrated somewhere else, which could trigger an ordinary, perhaps dangerous quake.

      • Re:can release as much energy (Score:4, Funny)

        by Anonymous Coward on Monday May 24, 2004 @01:18PM (#9239351)
        Another way to put is like this: Imagine a build-up of gas in a stomach. Perhaps a slow release of the gas into the intestinal tract occurs. This does release some energy, but now the stresses in the intestines are increased. Then comes the big fart, and relief ensues. Ahhhh!

        Or imagine a river with two reservoirs. The upper one releases energy slowly, filling the lower reservoir, which fills, then reaches bursting point. The energy release at one place does reduce the overall energy potential of the whole system, but increases the local energy of the lower reservoir.

        This same effect can occur with ANY quake or energy release, which can lower the overall energy level of the system, but may locally increase stresses somewhere else.

    • Re:can release as much energy (Score:5, Interesting)

      by TastyWords ( 640141 ) on Monday May 24, 2004 @01:18PM (#9239358)
      Why would kinetic energy necessarily guarantee a buildup of potential energy?

      Think about standing halfway up|down a flight of stairs and you have a package sitting on the stairs and you have it on a rope. Move either way (up or down) on the stairs. Does expending this energy mean a buildup is imminent? Of course not. If you are dragging it down the stairs, as it gets closer & closer to the bottom, the available potential energy is less & less. If you drag the package up the stairs, there is an obvious buildup of energy and if you were to bump the package or accidentally tug on the rope, the energy would be released. And anyone listening (measuring) without seeing the stairs, who would hear the package moving, wouldn't necessarily know which direction it was going - unless|until they learned out to measure a difference in the acoustics.

      I'm sure someone's going to shoot holes in this by claiming all sorts of exceptions or places where it doesn't work, but this is just a rough idea.

    • Re:can release as much energy (Score:5, Informative)

      by ackthpt ( 218170 ) * on Monday May 24, 2004 @01:23PM (#9239409) Homepage Journal
      Does this not imply stress is being released?

      The thing is, the plate as massive as it is in scale is elastic and these faults, like the San Andreas may run hundreds of miles. When there's a shift it may only move the whole plate a few inches in an area (or even feet in one example north of San Francisco where a fence was warped) that's a lot of mass to move and we're just standing on it like ants. Some pressure relieved in one locaction undoubtably builds pressure somewhere else, or even transfers presure to a parallel fault. This [usgs.gov] is a particularly good place to start when looking at the scope of things.

    • Release can add stress (Score:5, Informative)

      by Kozar_The_Malignant ( 738483 ) on Monday May 24, 2004 @01:37PM (#9239521)
      This seems counter-intuitive. However, it isn't that far-fetched. Imagine a laterally moving or strike-slip fault (the notorious San Andreas fault is an example). Obviously, motion of the plates on wither side of the fault releases energy. The thing to focus on is what is happening at the ends of the fault. There, the faults can get locked into other plates, and motion causes a build up of stress as motion of one plate is blocked by a stationary plate. Some geologists are concerned that this is happening at the southern end of the San Andreas fault in the San Gorgonio Pass area and at the northern end at the Mendocino Triple Junction.

  • I think it's scary... (Score:5, Insightful)

    by Mz6 ( 741941 ) * on Monday May 24, 2004 @01:06PM (#9239231) Journal
    Considering that the largest earthquake ever in Washington was a 7.3 in 1874 [usgs.gov] and that this was largely just discovered a few years ago, perhaps this is a precursor to something big about to happen? More recently was a 1949 earthquake that measured 7.1 near Olympia.

    From the Science Daily article..."Making that determination will help in understanding whether they are adding to or relieving stress in the Cascadia subduction zone off the Washington and B.C. coast, where the Juan de Fuca plate dives beneath the North American plate. The subduction zone is capable of generating great earthquakes, and scientists recently determined that a Cascadia earthquake in 1700 measured about 9.0 in magnitude."

    And Wired... "The coastal region of northwest Washington state and southeast British Columbia is prone to earthquakes, and scientist warn the area gets hit with a devastating shake of magnitude 9 about every 500 years."

    Sure.. we're only 196 years off the 500 year mark since the last 9.0, but for it only to pop up a few years ago makes it seem very ominous.

    This data, while very interesting, could still go 2 ways. It is helping to alleviate and prevent major earthquakes in that area, or it's a major precurosr to a huge event that could happen in the near future. The hard part? What is considered teh near future... tomorrow? 5 years? 10 years? Guess we'll have to wait and see.

    What's even more interesting is that I have yet to see any reports about this coming from any of the California plates, perhaps it hasn't been found or tested for or it's just not there.. Who knows.

    • How come no one (Score:3, Interesting)

      by 2names ( 531755 )
      ever mentions the fault line that runs along the Mississippi river? Didn't a major quake in the recent past cause the river to run backwards?

    • Re:I think it's scary... (Score:5, Interesting)

      by TastyWords ( 640141 ) on Monday May 24, 2004 @01:11PM (#9239287)
      You want scary?

      Here in the midwest (Indiana) we're anxiously awaiting the next quake from the New Madrid fault. The last time it peaked, the Mississippi reversed direction for two days and the ground rippled like waves of four-to-five feet.

      Imagine that with the fact most buildings in the midwest, whether it's Chicago, St. Louis, any other city familiar to you - if you aren't familiar with all of the cities, haven't been built to withstand an earthquake. After all, they don't come along often enough to warrant that type of concern and|or expense.

      • Really Scary (Score:5, Informative)

        by Kozar_The_Malignant ( 738483 ) on Monday May 24, 2004 @02:00PM (#9239724)
        I was involved in planning for insurance company response to a quake on the New Madrid fault in the early 90's. Living in California, I'm used to quakes and have lived through some bad ones. A quake on the New Madrid fault would be a monumental disaster on many levels. First, as the writer above points out, the building is not to earthquake standards. Damage would be horrific. Places like Memphis would simple cease to exist.

        Second, not only are codes inadequate, but the geology of the area contributes to the problem. The solid parent material (bedrock) allows propagation of the energy over a much wider area than in California. The historic New Madrid quakes cause church bells to ring in Boston. This coupled with the fact that many cities and towns are built on alluvial surface material that undergoes liquifaction during a quake means that once the energy reaches a remote area, it will still do a lot of damage.

        Third, the extremely high market penetration of earthquake insurance in the commercial and homeowners insurance markets in the midwest means this would be a world-wide financial disaster far exceeding that of the 9/11/01 World Trade Center loss. Earthquake insurance in most midwest states is dirt cheap and has relatively low deductibles. Everybody has it. Here in California, it is expensive and has very high deductibles. Most people don't have it. If you do the math here, you are better off putting the money you would spend on premiums into mitigation efforts like foundation bolts, masonry reinforcements, etc. Our calculations in the 90's on the dollar loss from a repeat of the New Madrid quakes indicated that a Great Depression style financial collapse was not just possible, but likely.

        This is seriously scary shit. The New Madrid Earthquake scare has passed, and not too many people in the midwest are doing any real earthquake planning. The next quake on the New Madrid fault will happen, we just don't know when.

        • Re:Really Scary (Score:5, Informative)

          by dgatwood ( 11270 ) on Monday May 24, 2004 @02:35PM (#9240028) Homepage Journal
          I don't think it would be as bad as you think.

          So back about 14 years ago, a guy named Iben Browning gave folks a big scare. Even though it never panned out, a lot of older homes were retrofitted during that period, including basic things like tying homes to their foundations, etc.

          The state of Tennessee also went through and systematically reengineered many thousands of bridges to make them more earthquake-safe, adding additional ties to ensure that the hooks that hold them in place won't fail if the bridges flop around. They went through and retrofitted all of the buildings on university campuses to comply with strict earthquake codes, including steel cords through all of the bricks in any sufficiently large overhang. I don't think even California's earthquake code is that strict.

          Also, a large portion of the weaker buildings, at least in West Tennessee (where the fault in question lies) have been decimated by tornadoes in the past few years, including two devastating hits on Jackson and I believe at least one in Memphis (though I could be remembering wrong). The buildings that resulted from that should meet earthquake code. Mobile homes were designed to be moved, so they shouldn't collapse. That leaves the older homes, most of which have earthquake ties, eliminating the largest cause of damage.

          That's not to say that there won't be damage. A nine point will pretty much level anything no matter what you do. Fortunately, that big a quake isn't likely. Odds are in favor of more like a 7 point quake. I wouldn't expect it to be much worse than the equivalent quakes in California---maybe not as bad, since so many older homes and buildings have been brought at least partially up to code.

      • I installed a system at the power plant in New Madrid around 1991. I went back to my hotel room where I had been watching the baseball game in San Francisco and found there had been a huge quake. So Peter Jennings has his expert on who says "Well Peter, the largest quake was actually in New Madrid Missouri!" So I turn and see this big "New Madrid" sign out my window... no wonder I hate business trips.

        The locals told me about the quake: They said the fields rose in 30 foot waves as the soil liquified, the r
    • Comment removed based on user account deletion

    • Re:I think it's scary... (Score:5, Informative)

      by Ann Elk ( 668880 ) on Monday May 24, 2004 @01:13PM (#9239302)
      And Wired... "The coastal region of northwest Washington state and southeast British Columbia is prone to earthquakes, and scientist warn the area gets hit with a devastating shake of magnitude 9 about every 500 years."

      Google for cascadian subduction zone [google.com] for information on the cause of many of the Pacific Northwest area earthquakes. And yes, the experts predict a huge (>= 9.0) quake in this area Real Soon Now (within a century or two).

    • Re:I think it's scary... (Score:4, Funny)

      by happyfrogcow ( 708359 ) on Monday May 24, 2004 @01:18PM (#9239355)
      Fear! Uncertainty! Doubt! Speculation! Oh My! The world is comming to an end! Maybe we should have a Giant Space Laser that reduces stress in the earth's plates! When will the world end? Today? Tommorow? Yesterday, and this is just the afterlife? ...time for more coffee. Is this a slow news day, or what?

      • Have you not heard of my enormous, genetically engineered Earthquake Relieving Gophers? My gophers will tunnel under the earth, lubricating fault zones with their specially designed gopher poop.
        • surely. but in a game of lasers-gophers-bottlecaps, lasers beat gophers. so try getting your enormous genetically engineered Earthquake Relieving Gophers past my lasers.

          so obviously we should use bottlecaps. because they beat lasers. Hmm, but gopher beats bottlecaps... dilemas dilemas.

    • Re:I think it's scary... (Score:4, Insightful)

      by Blakey Rat ( 99501 ) on Monday May 24, 2004 @01:28PM (#9239437)
      What's really scary is that the local government isn't doing crap about making the city more earthquake safe.

      Look at the Alaskan Way Viaduct, for example. An almost identical freeway in California collapsed in the 1989 earthquake. There's been a lot of lip-service about making the viaduct safe, but the only changes I've seen is the installation of a few metal braces on a couple of the supports. That's not good enough!

      That viaduct needs to be torn down. If there's any weak point in Seattle's earthquake strategy, that's it.

    • Re:I think it's scary... (Score:5, Insightful)

      by WhiteBandit ( 185659 ) on Monday May 24, 2004 @02:28PM (#9239961) Homepage
      Also note the 500 year mark is fairly arbitrary in that it is an average.

      Down here in Southern California, we've looked at a spot where the San Andreas fault crosses through the Cajon Pass. Digging trenches and things across the fault reveals movement on average every 180 years or so.

      The last time that segment of the fault moved was in 1812. 192 years and counting. When you actually plot out when earthquakes occured, you find major events happening as close to 60 years apart to as far away as 220.

      So basically, you guys might be due for an earthquake fairly soon... or you might not! ;)
    • > What's even more interesting is that I have yet
      > to see any reports about this coming from any of
      > the California plates, perhaps it hasn't been
      > found or tested for or it's just not there..
      > Who knows.
      California's tectonics are significantly different than the OR-WA-BC situation. The Subduction Zone we have up here in the Silicon Forest puts us at much greater risk of The Big One.

      An Oregon Department of Geology scientist gave a Tsunami presentation at my Red Cross Disaster Respo

  • I'm still waiting.... (Score:5, Insightful)

    by TastyWords ( 640141 ) on Monday May 24, 2004 @01:07PM (#9239239)
    ...to hear whether piezoelectricity can be used to detect quakes as well. With all of the smashing and crashing going on, one would think it would have the potential to generate radio waves such that a properly tuned instrument could receive|detect the signal.
    • As far as I know, some geologist from Japan is working on exactly this concept. Didn't he predict a smaller quake in Japan this spring? (Sorry, no time to google myself...)

      • Re:I'm still waiting.... (Score:1, Informative)

        by Anonymous Coward
        Yes, he predicted one on Tokyo.. it happened like 2 days after his predicted date.. so it needs more work but it was close.. there was a show on tv a year ago about predicting earthquakes.. i forget what they were doing but they had maps of where possible earthquakes would happen.. and he predicted like several major earthquakes.. but he couldnt help anyone because if he said "you're going to have an earthquake on BLAH".. no one would believe him
      • The reason I'm still waiting is I suggested this to some of my college professors when I was in my early teens and it was thought to be possible but without a lot of studying....

      • Re:I'm still waiting.... (Score:5, Interesting)

        by WhiteBandit ( 185659 ) on Monday May 24, 2004 @02:15PM (#9239859) Homepage
        Dr. Keilis-Borok at UCLA and his team are claiming to have predicted two earthquakes [ucla.edu]. One in Japan as well as the one in San Simeon.

        Using similiar techniques, they are prediciting an earthquake of a minimum magnitude 6.5 in the Southern California desert by September 5. It will be interesting to see if this pans out.

        Interestingly enough, I am have an internship in seisomology with the So. Cal. Earthquake Center this summer and will be working at UCLA. I have a feeling it is going to be quite busy! :)
        • It is easy to predict earth quakes. All you have to do is accurately model the convection currents of the magma layer as well as heat generated at the core and the stresses the flow induces on the crust. Take in account all the orbital stresses induced upon the planet from the sun moon etc.. Correctly measure and map the friction of coefficient on fault lines. Calculate and measure the strength of the crust and it's resistance to deformation at fault lines. And last but not least figured out the current str
      • A story in the Fall 1990 WHOLE EARTH REVIEW #68, pp. 101-104, documents a 1984-1987 USGS study which showed a 70% correlation between radio signals on 200 Hz - 100 KHz. (the signals which BPL, if permitted by the FCC, will largely block).

        Multiple citations are included to other research at the end of the article [rexresearch.com].

        I think I will build one, even though when I bought my new home, it was built in Zone Green [portlandmaps.com].

    • Re:I'm still waiting.... (Score:5, Funny)

      by gwernol ( 167574 ) on Monday May 24, 2004 @01:22PM (#9239395)
      ...to hear whether piezoelectricity can be used to detect quakes as well. With all of the smashing and crashing going on, one would think it would have the potential to generate radio waves such that a properly tuned instrument could receive|detect the signal.

      It usually isn't too difficult to detect earthquakes. Trying to stand up and failing is a perfectly good indicator that (a reasonably large) one is going on :-)

      Plus there's seismographs and whatnot that are really pretty good now.

      The much more interesting problem is how to predict earthquakes. For this, piezoelectric mechanisms offer no advantage over "conventional" methods.
      • I should have said predict. I'm so used to the theory I say "detect in advance".

        Sorry.
        • I should have said predict. I'm so used to the theory I say "detect in advance".

          Fair enough, but seriously, can you point to a link to this theory? As I understand it the issue with predicting major quakes isn't being able to gather enough evidence (though more evidence is usually good) but being able to determine what patterns in the evidence fortell a large magnitude event. Modern seismology is pretty good at detecting minor and/or deep quakes that can't be felt at the surface. Just gathering better i
    • You'd need to know the material properties of the material involved with the quake. Since you can't be right at the fault, several miles down when the quake (or slippage) occurs, you have a really hard time saying exactly what is down there. You can make guesses based on previous seismic data, or samples taken from the surrounding rock, but you need to sample many times.

      The other thing is that the radio waves may be so low in frequency that they are smothered by the local noise, the thermal noise in yo
    • This sort of thing has been tried without much success so far. There have been intriguing electromagnetic signals recorded over the years (e.g. see this table [neu.edu]). However, nobody has been able to come up with a method of prediction using EM that has achieved acceptance among earthquake seismologists. It's much easier to find funny signals after a quake than before.

  • Politically Incorrect (Score:5, Funny)

    by Anonymous Coward on Monday May 24, 2004 @01:08PM (#9239249)
    Do *NOT* call them slow...

    ...they're "special" earthquakes.

    :: ducks ::

  • Can this energy be tapped (Score:1, Interesting)

    by Anonymous Coward

    is it possible to extract any energy from these massive events ? or are they too un-reliable and too much energy would be required to make harnessing it woth while ?

    AJS

  • Tectonic plates (Score:4, Interesting)

    by Plaeroma ( 778381 ) <plaeroma @ g mail.com> on Monday May 24, 2004 @01:09PM (#9239258) Journal
    Can someone explain to me the difference in a 'slow earthquake' and just general plate movement? Cause from I just read, I couldn't differentiate between the two.

    • Re:Tectonic plates (Score:5, Informative)

      by geomon ( 78680 ) on Monday May 24, 2004 @01:17PM (#9239340) Homepage Journal
      "Slow" earthquakes are a bit of a misnomer. The energy released in a slow earthquake is the same as the energy released by a catastrophic quake. It is just released over a longer period of time.

      General plate movement creates both slow and catastrophic quakes; plate tectonics is the engine driving the stress that creates earthquakes.

      • Isn't this just similiar to the aseismic slip conditions you get along certain parts of the San Andreas Fault? (North of Parkfield and also through Hollister).

        Perhaps the differentiation is the fact that aseismic slip/creep is happening continously through those segements while the movement in these "slow quakes" is only confined over the course of a small interval (14 months or something?).
        • Yeah, the time boundaries between creep and this kind of phenomenon are kind of fuzzy and subjective. When does creep become a slow quake, when is a quake not a quake, etc.

          Since this falls in the gap between creep and quake, you should expect a whole subdiscipline to appear in a few years dedicated to the study of long duration quakes. They will provide the theoretical and emperical basis for dividing creep from slow quake.

          One thing that definately helps establish a boundary is the depth of the energy rel

  • You could also add (Score:5, Informative)

    by geomon ( 78680 ) on Monday May 24, 2004 @01:09PM (#9239259) Homepage Journal
    The seismic staff [pnl.gov] at the Pacific Northwest National Laboratory [pnl.gov]

    We contribute to the UoW by maintaining the Eastern Washington Seismic Monitoring Network.

  • add to or relieve stress (Score:5, Insightful)

    by ron_ivi ( 607351 ) <sdotno@NosPAM.cheapcomplexdevices.com> on Monday May 24, 2004 @01:09PM (#9239271)
    "One key question the scientists are trying to answer is whether these slow earthquakes add to or relieve stress in the tectonic plates, which could ultimately help to predict major earthqakes."

    Wouldn't it do both. I.e. relieve stress in the spot that slipped, and add to stress in the spots where the plates are still binding?

    • Re:add to or relieve stress (Score:5, Interesting)

      by geomon ( 78680 ) on Monday May 24, 2004 @01:24PM (#9239412) Homepage Journal
      Yes, the stress relieved at one site may be trasferred to another along the plate margin. But exactly where in the system it is taken up determines whether the "receiving" plate margin will react in a catastrophic manner. Some sites may behave in a plastic (quasi-elastic) fashion and the stress will be dissapated in a slowly developing folded crust. Others will absorb the stress along brittle margins and will eventually react in a non-elastic fault.

  • More Info Is Always Good (Score:5, Informative)

    by ackthpt ( 218170 ) * on Monday May 24, 2004 @01:11PM (#9239288) Homepage Journal
    The conventional wisdom among my friends and neighbors is, if it has been quiet for too long, it's a bad sign. I've been through a couple 5.0+ earthquakes, the slow rolling type 15-20 seconds and they're pretty nerve wracking, though much preferble to the sudden jolt 3.0+ shockwaves. In Monterey, CA I felt the last 5.4(?) a couple weeks ago down near Paso Robles (probably an aftershock of the 6.5 quake [usgs.gov] Dec 2003.) As the 2003 illustrates, there are quakes looming in places we're quite unaware until they strike (i.e. Seattle a couple years back), thanks to the complexity of the faults (it's not like there's one fault line, but a who series of fractures along the edge of the plate.) It does seem all the rage of the past few years has been in trying to detect pending quackes along long silent faults, long as in perhaps hundreds or thousands of years.

    Still, as far as I have seen the worst to hit North America since europeans settled here struck in a series between 1811 and 1812 near New Madrid, Missouri [usgs.gov], one of which reportedly run church bells as far away as Washington DC.

    Some day the big one will hit and all the land east of the San Andreas Fault will slide off into the Atlantic Ocean

    • If you've lived in Seattle, you know that the entire state is a major earthquake zone. I live in Southern California now (lancaster), but I had some fun in the last few major quakes we had there. It's common knowledge up there that the beautiful Cascade Mountains are almost all active volcanos, the rivers flood annually, the windstorms are irritating, and the earthquakes are generally in the range of 3-4.5 if you can feel them.

      The geologists up there keep saying that Washington State is due for a huge
      • The geologists up there keep saying that Washington State is due for a huge magnitude quake, something on the order of 8.0. There are also fault lines crisscrossing the Seattle area, Puget Sound, and the outlying areas.

        Undoubtably the west coast was very geologically active over a long period in the distant past. There are vast a lava beds throughout eastern California (driving up 14/395) from Mojave makes this abundantly clear, though these beds go on for hundreds of miles all they way up into northern

    • Still, as far as I have seen the worst to hit North America since europeans settled here struck in a series between 1811 and 1812 near New Madrid, Missouri, one of which reportedly run church bells as far away as Washington DC.

      I read the link, and it was a pretty weaselly way of describing the quake. It tries to give the impression that it was the largest quake to hit North America, but that is not correct. The largest to hit North America is the 1964 quake in Alaska. Less than two years ago, a 7.9 qu

  • Better article found (Score:5, Informative)

    by Mz6 ( 741941 ) * on Monday May 24, 2004 @01:13PM (#9239298) Journal
    Interview with a USGS official on "slow" quakes back in 1992. Click here! [scec.org]

  • Give or take? no its Give AND take. (Score:1, Interesting)

    by Anonymous Coward
    One key question the scientists are trying to answer is whether these slow earthquakes add to or relieve stress in the tectonic plates, which could ultimately help to predict major earthqakes."

    Knowing nothing about Earthquakes, naturally i have an opinion.

    any time you have irregular shaped objects moving in oposite directions against each other you are going to have a transfer of "stres" from various points along the "fault line" so, while stress is removed from one location it is usually only getting tra
    • look above. that's why I suggested piezoelectricity. Pressure can be exerted upon a rock (even by another rock) and it will generate radio waves. So when you're playing rock, paper, scissors, and the two rocks happen to generate enough pressure, it'd be a matter of trying to know what radio frequencies to know to monitor and get a signal. There are some obvious questions about this - in addition to whether it would work; how broad the frequency spectrum you'd have to monitor, how much lead time you'd get,
      • An interesting idea, but I don't think it could tell you when a quake will occur. If you did manage to acurately measure how much pressure has built up using this method, you could say "if it slips today, we'll have an X.Y magnitude quake" -- but how would you know whether it'll slip and release that pressure today, or just build up for for an X.Z magnitude quake tomorrow? You need to know a lot more than how much pressure is built up to be able to predict when it'll be released.

        Still, I probably would

  • Possibilities (Score:3, Interesting)

    by Ra5pu7in ( 603513 ) <ra5pu7in@@@gmail...com> on Monday May 24, 2004 @01:18PM (#9239361) Journal
    Just some guesses:

    A "slow" quake could release stress along a certain section of the plates, but build up pressure along another section further away - thus leading to a large quake along the second section.

    A "slow" quake could ramp up to a large quake if the slippage reaches a point where the plates have less friction against each other.

    The faults don't only shift when a major earthquake occurs. A "slow" quake may shift the two plates closer to a point that can only shift through a large quake.

    Obviously, IANAS or IANAG - and as neither scientist nor geologist - these are mere guesses based on what I do know of earthquakes.

  • Encourage them!! (Score:5, Interesting)

    by sameerdesai ( 654894 ) on Monday May 24, 2004 @01:21PM (#9239387)
    I believe a research into predicting earthquakes should be encouraged and given more funding. I am saying this because of my own experience. About 3 years ago, my city and lot of cities around my state experienced a major quake reading 7.8 (Bhuj quake in India) that killed more than 30,000 people. I was sleeping when this happened and it was terrifying. Never in my dream I had imagined my city was in earthquake prone zone. Looking at the rumble and bodies gave me shivers. I believe if such a thing is developed so many lives could be saved (if not property). Also this might help in identifying earthquake zones (if I remeber correctly they classify them in zones based on likelihood of having an earthquake) and that can give an impetus to civil authorities to build earthquake proof houses minimising property damage as well. Just my thoughts.
    • There is a big debate in Japan over this - should we encourage earthquake prediction or not?
      I personally feel earthquake prediciton shouldn't be stressed in Japan. It really doesn't do much for us. As long as you live in this country, a big one is going to come, sooner or later.
      It probably would save more lives if we would pour money into making buildings earthquake-resistant and raising awareness on how to reduce earthquake damage (for example, by anchoring large furniture).
      I additionally have to add tha
      • Hmm Makes sense!!! This way we would fall into two categories: Regions in frequent earthquake zone and Regions that are not. This kind of research will help in latter. Besides this research will help in identifying and separating these regions and hence proper distribution of the "kind of research" would be attained. As for e.g. the research on earthquake resistant buildings would help Japan on the other hand research of predicting earthquakes will help cities which don't normally do receive earthquakes. Th

  • Predictable Earthquakes (Score:5, Informative)

    by CharAznable ( 702598 ) on Monday May 24, 2004 @01:21PM (#9239390)
    I'm from Costa Rica, which has its share of earthquakes. Common wisdom states that the earthquake cycle comes around every 30 to 40 years, and the lasts about 10 years. During that time, a couple of >6.0 earthquakes are expected. This works like clockwork. In 1910, an earthquake levelled the city of Cartago. More high profile earthquakes happened in the 50's, then 30 years of silence, and then the new wave started around 1984 and continued into the early 90's. It now appears to have subsided. In 1991, I experienced the might of a 7.1 quake. I almost crapped my pants.

  • What did one stress fracture... (Score:4, Funny)

    by miketo ( 461816 ) <miketo@nw l i n k . com> on Monday May 24, 2004 @01:24PM (#9239414)
    ...say to the other stress fracture during an earthquake?

    "Hey, it's not my fault!"

  • I've no idea why... (Score:4, Funny)

    by Phidoux ( 705500 ) on Monday May 24, 2004 @01:28PM (#9239446) Homepage
    ... but this whole Teutonic Plate Movement thing sounds kinda scary and images of blonde hair and blue eyes spring to mind.
    • " ... but this whole Teutonic Plate Movement thing sounds kinda scary and images of blonde hair and blue eyes spring to mind."

      Hmm, `Teutonic Plate Movement`, Isn't that the study of German Denture looseness? (Maybe we should invest in polygrip? };-> )

  • Give and Take (Score:3, Interesting)

    by bubba_ry ( 574102 ) on Monday May 24, 2004 @01:34PM (#9239499)

    One key question the scientists are trying to answer is whether these slow earthquakes add to or relieve stress in the tectonic plates

    I am by no means a geologist, but I'd speculate that the slow earthquakes (maybe earthquakes in general?) add stress to some plates and relieve stress in others, somewhat similar to the law of conservation of mass in physical science. That energy has to go somewhere...

  • Why don't they (Score:4, Funny)

    by millahtime ( 710421 ) on Monday May 24, 2004 @01:45PM (#9239591) Homepage Journal
    Why don't they just call their local psychic. There are even 1-800 numbers for that.
    • Why should I have to _call_ a psychic?

      If they are really psychic, why don't they call me when they know I need them?

      • Just because they are psychic, doesn't mean they are completely altruistic. Perhaps they are only willing to help those who are willing to pay them regularly through their 1-900 numbers.

  • Akamai Mirrors (Score:2, Informative)

    by karmatic ( 776420 )
    Here [t28.net] and Here [akamaitech.net].
  • Is anyone looking into Dr. Samantha Hill's theory from the movie "10.5", or are we not going to take it seriously because it was just a movie?
    ----
    The Analysis Process [blogspot.com]

  • A great book with the 'big picture' (geologically) (Score:4, Informative)

    by DieByWire ( 744043 ) on Monday May 24, 2004 @04:37PM (#9241368)
    John McPhee's 'Annals of the Former World.'

    If you're really after the earthquake stuff, just read 'Basin and Range' and 'Assembling California.' (two of the four books that make up 'Annals of the Former World').

    In these books, McPhee travels I-80 with a geologist who's an expert in the area they're covering. Each book is about the geology, the geologist, and the road trip. Great read, and you'll end up learning something, whether you intend to or not.

  • is breakfast syrup. :P

Slashdot Top Deals

Physician: One upon whom we set our hopes when ill and our dogs when well. -- Ambrose Bierce

Close