Tokyo earthquake predicted by astronomer?

  1. Ivan Seeking

    Ivan Seeking 12,535
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  2. jcsd
    Earth sciences news on Phys.org
  3. Tsu

    Tsu 638
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    Can any of the geologists here answer my question that I posted in Ivan's thread?
     
  4. Ivan Seeking

    Ivan Seeking 12,535
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    Interesting: A striking [earth shaking] coincidence?
    http://www.msnbc.com/news/971921.asp?pne=msntv

    This second - estimated as an 8.0 - event was off by about 660 miles and one week from the prediction. The chance of coincidental success appears to be about 1:600 in this case.

    The first event was about three days late, and it was a 5.5 instead of a 7.0.
     
    Last edited: Sep 26, 2003
  5. russ_watters

    Staff: Mentor

    Based on what?

    Predicting earthquakes in Japan is like predicting snow in Utah or fog in England: not very difficult if you don't have to be too specific about it.

    From the first article:
     
    Last edited: Sep 26, 2003
  6. Ivan Seeking

    Ivan Seeking 12,535
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    This estimate is based on data from the USGS. There have been 9 quakes in excess of 7.0 in Japan since 1891. Please see the linked thread in the S&D forum.

    https://www.physicsforums.com/showthread.php?s=&threadid=6004
     
  7. Ivan Seeking

    Ivan Seeking 12,535
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    Yes, so? The article was printed before the quakes.
     
  8. russ_watters

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    From your post it still isn't clear how you calculated that probability. Its really not that hard. From your numbers, the magnitude 5.5 earthquake was off by 200x from the predicted magnitude 7.0. Then multiply that by the frequency of magnitude 5.5 earthquakes in Tokyo (if I had to guess, I'd guess one or two a year). That would make the odds at best 1:200,000 of being that close on picking a day and a magnitude.
     
  9. Ivan Seeking

    Ivan Seeking 12,535
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    Where did you get this?

    On the the average, one quake over magnitude seven every 600 weeks for all of Japan. There was a 5.5 in Tokyo, and then a 7.0 and an 8.0 a week later; about 660 miles north. The big quakes are what most interest me. These are fairly rare events as indicated by the USGS data. To miss a 7.0 anywhere in the neighborhood by only a week ain't bad. I am sure that you would normally argue strongly against an explanation that only has odds of 1:600 of being true.

    Also, it is not clear how to calculate the accuracy of the original quake prediction. His exact method is not given; it may ultimately be based on energy, magnitude, or even as a linear function of the magnitude value. The fact is, this astronomer went public with a risky prediction. A week later, it appears that against odds of at about 1:600, he may have gotten it right. A lot of the interpretation of success seems to depend on his method; but even if we understood his method, we may have no theory to explain the observations.

    Edit: Amateur Astronomer
     
    Last edited: Sep 27, 2003
  10. Do we have any details on the theoretical background of his predictions?
     
  11. Ivan Seeking

    Ivan Seeking 12,535
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    I couldn't find his website the first time I looked. It popped right up this time.

    http://www.jpinfo.ne.jp/yatsu/yochi/egaku/
     
    Last edited: Sep 27, 2003
  12. Ivan Seeking

    Ivan Seeking 12,535
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    Here are the initial data and comments

    Magnitude 8.3 HOKKAIDO, JAPAN REGION
    2003 September 25 19:50:06 UTC
    Preliminary Earthquake Report
    U.S. Geological Survey, National Earthquake Information Center
    World Data Center for Seismology, Denver



    Magnitude 8.3
    Date-Time Thursday, September 25, 2003 at 19:50:06 (UTC) - Coordinated Universal Time
    Friday, September 26, 2003 at 04:50:06 AM local time at epicenter
    Time of Earthquake in other Time Zones
    Location 41.83N 143.83E
    Depth 33.0 kilometers
    Region HOKKAIDO, JAPAN REGION
    Reference 135 km (85 miles) SSW of Kushiro, Hokkaido, Japan
    245 km (150 miles) NE of Hachinohe, Honshu, Japan
    245 km (155 miles) SSE of Asahikawa, Hokkaido, Japan
    770 km (480 miles) NNE of TOKYO, Japan

    Location Quality Error estimate: horizontal +/- 5.7 km; depth fixed by location program
    Location Quality
    Parameters Nst=199, Nph=199, Dmin=575.6 km, Rmss=0.84 sec, Erho=5.7 km, Erzz=0 km, Gp=34.2 degrees
    Source USGS NEIC (WDCS-D)
    Remarks At least 400 people injured, extensive damage, landslides and power outages occurred and many roads damaged in southeastern Hokkaido. A tsunami generated with an estimated wave height of 1.0 meter along the southeastern coast of Hokkaido. Felt strongly in much of Hokkaido. Also felt in northern and much of central Honshu as far south as Tokyo. Recorded (6L JMA) in southern Hokkaido; (5U JMA) in parts of eastern Hokkaido; (5L JMA) in central Hokkaido; (4JMA) in parts of Hokkaido and northern Honshu; (3 JMA) in southern Iwate, Akita, Miyagi, Yamagata and northern Fukushima; (2 JMA) in southern Fukushima, northern Niigata, eastern Tochigi, Ibaraki, Saitama, Tokyo, Chiba, Kanagawa, eastern Shizuoka and eastern Yamanashi; (1 JMA) in eastern Gumma and parts of Nagano Prefectures. Also recorded (1 JMA) on Miyake-jima and Hachijo-jima.


    Tectonic Summary
    The preliminary location and focal-mechanism of this earthquake imply that it occurred as the result of thrust-faulting on the plate interface between the overriding North American plate (which extends into the northeast corner of the Eurasian landmass) and the subducting Pacific plate. The Pacific plate is moving west-northwest at a rate of about 8.2 cm per year relative to the North American plate. In addition to experiencing great thrust earthquakes that originate on the interface between the plates, eastern Hokkaido experiences great earthquakes that originate from the interior of subducted Pacific plate. The earthquakes of March 4, 1952, and May 16, 1968 (cited below) were interface-thrust earthquakes, whereas the earthquake of January 15, 1993 (cited below) occurred within the interior of the subducted Pacific plate. The recent earthquake appears to have involved rupture of the same section of the plate interface that ruptured in 1952.

    Magnitude 8 and greater earthquakes are capable of devastating large areas. The shallow September 25 Hokkaido earthquake occurred about 60 km offshore. If the earthquake had occurred directly beneath a populated region, damage would have been more severe.

    Previous Deadly Earthquakes in this Region
    Date UTC Magnitude Fatalities Damage
    1952 March 4 8.6 31 31 killed, 72 injured; 713 houses destroyed, 5,980 damaged. 28 killed and warehouses destroyed at Kushiro. 3 killed and 309 houses destroyed at Kiratapu. 1,000 houses destroyed or damaged at Shiranuka and 400 schools collapsed at Sapporo. 10-foot tsunami.
    1968 May 16 7.9 48 Damage estimate at 25 million USD.
    1993 January 15 7.6 2 614 injured and substantial damage (VI JMA) at Kushiro, Hokkaido and Hachinohe, Honshu. Felt (V JMA) at Hiroo, Nemuro, Obihiro, Otaru and Urakawa; (IV JMA) at Hakodate and Tomakomai; (III JMA) at Sapporo, Hokkaido. Felt (IV JMA) at Aomori and Morioka; (III JMA) at Akita, Fukushima, Sendai, Tokyo and Yokohama, Honshu. Also felt (VII) on Shikotan and (VI) at Kurilsk, Kuril Islands. Landslides and subsidence occurred in the epicentral area.

    The last great earthquake (magnitude 8 or greater) in the world was a magnitude 8.4 that occurred on June 23, 2001, near the coast of Peru. This earthquake killed at least 75, including 26 killed by the associated tsunami.

    http://neic.usgs.gov/neis/bulletin/neic_zdap.html
     
  13. Nereid

    Nereid 4,014
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    Where can one find a complete set of Kushida's public predictions (including date, time, and 'publication'), and a complete set of earthquakes in the areas monitored over the time he published his predictions (and go back a week before the start)?
     
  14. Ivan Seeking

    Ivan Seeking 12,535
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    This is the information on the quake near Tokyo that was first associated with his prediction.


    http://neic.usgs.gov/neis/bulletin/neic_zcat.html
     
  15. Ivan Seeking

    Ivan Seeking 12,535
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    Many comments on earthquake prediction:

    IUGG 2003 Scientific Program
    example:
    http://www.jamstec.go.jp/jamstec-e/iugg/htm/abstract/abst/jws01_p/p2.html

    Other related info:
    Earthquake
    All the current Earthquake news

    http://earthquake.newstrove.com/
     
    Last edited: Sep 27, 2003
  16. So in effect, it appears to be an empirical observation, based on statistical correlations? I think I understand the doubt that was placed on his predictions... Hmm, it very interesting, but I think we should wait for more results before we can decide there is something in his method.

    As for his hypothesis for the mechanism...
    This appears to be the critical part of it. Would it be possible to cut out the meteor/radio bit and just directly measure for this to validate his hypothesis? And if this was the case in this earthquake, can this form part of a general method for all earthquakes? (Some rocks may respond like this, but could this just be a lucky break?)
     
  17. russ_watters

    Staff: Mentor

    Ah, but the question was what about his other predictions? Regardless of odds (since odds are tough, I'll let that line go) if he's made thousands of predictions and this is the only one that was even close, that would call his theory into question.
     
  18. Ivan Seeking

    Ivan Seeking 12,535
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    True. I assumed [bad thing to do] that since his prediction caused such an uproar, he has not made too many false predictions in the past.
     
  19. russ_watters

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    Or maybe none. People tend to jump on the first prediction and if thats wrong they forget the person even existed. Pretty soon, 600 people have made predictions and lo and behold (with 1:600 odds), one gets a hit. EVERYONE predicts earthquakes. Hell, I have a bunch I'm predicting. I won't tell you when or where though - you have to buy my book.
     
  20. Ivan Seeking

    Ivan Seeking 12,535
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    You are of course absolutely correct; mark that down I won't say it often. However, , the potential differences here are that first, he claims to be following empirical evidence that can be subjected to scrutiny. Next, unless you can find a significant number of near term predictions for a quake >= 7.0 in Japan, I don't think these predictions exist. Finally, even if these predictions did exist, he still only had a 1:600 chance of being correct.

    My main point is not that he was right but that he deserves to make his case. Unfortunately, he may have no idea how to interpret this event himself. Clearly he does not have the location and timing nailed down.

    If you were a geologist working on earthquake prediction, would you ignore this event?
     
  21. Nereid

    Nereid 4,014
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    Surely the first (one of the first?) things to do is look at the track record and what the prediction(s) actually are.

    To repeat what I said elsewhere, Did this guy make public, ahead of time, ALL his predictions? If so, we can assess his track record, by making sure we match (or not) his predictions against actual earthquakes, and vice versa.

    It would also be a good idea to write down, before looking at all his predictions, how you will assess the predictions, against actual earthquakes (and vice versa). This will help to avoid (unconscious) bias in the assessments themselves; it's always harder to do this after you've looked at the data.

    One area where the assessment protocol needs to be particularly careful is the magnitude. As you point out, the Richter scale is logarithmic, and IIRC earthquake magnitudes follow a power law quite closely. This would suggest, for example, that a prediction of a magnitude 6 earthquake and an observed one of 5 should carry a different weight in any assessment from a prediction of 5 and an observed magnitude 6 quake.
     
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