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Asteroid hitting the Earth and causing a devastating Tsunami

  1. Jan 3, 2005 #1
    Does anyone know the calculation (asteroid size..etc), for an Asteroid hitting the Earth and causing a devastating Tsunami of the propotions as seen in Indonesia?

    It seems to me that I had heard that an Asteroid the size of a VW beetle, if hitting the earth head on, and landing at the same location off Sumatra, would cause a Tsunami more devastating than the current natural disaster, is this possible?
  2. jcsd
  3. Jan 3, 2005 #2
    It think one just a quarter mile in diameter (1400 feet) like 2004 MN4 would create a wave of 1000 feet high traveling 800 Mph into the shore creating regional devastation. It was predicted to hit April 13th @ 9:36 pm 2029 a few days ago but futher study shows it will miss.
  4. Jan 3, 2005 #3


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    HERE it is. It doesn't say anything about a tsunami unfortunately, but putting in a 1400ft object at 8 miles/sec velocity gives a 5.5 earthquake 100 miles from the impact point. I think that's in the ballpark, if a little smaller, than what was felt from this earthquake.
  5. Jan 3, 2005 #4
    The 5.5 figure refers to the magnitude at the epicenter or point of impact. You can change the distance from point of impact and the Richter magnitude stays the same.

    It is not in the ballpark. To get a 9.0 Richter reading, I input:

    • Distance from Impact: 200.00 km = 124.20 miles
    • Projectile Diameter: 4000.00 m = 13120.00 ft = 2.48 miles
    • Projectile Density: 3000 kg/m3
    • Impact Velocity: 17.00 km/s = 10.56 miles/s
    • Impact Angle: 45 degrees
    • Target Density: 1500 kg/m3
    • Target Type: Crystalline Rock

    My impact velocity is greater, and my projectile diameter is massively greater.
  6. Jan 3, 2005 #5
    Great site, thanks!
  7. Jan 3, 2005 #6
    If it hit in 2000 feet of water and near the coast it would be much much worse.
  8. Jan 7, 2005 #7


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    Double check the math? An asteroid that size would cause global (not regional) devastation. (comparison: The KT-event object was about 6 miles wide.)

    A UK report on near-earth object hazards (Sept 2000) predicts significant tsunamis from an 200-300 meter asteroid. It predicts global-scale tsunamis for 1.7 km objects
    see chapter 3 of http://www.nearearthobjects.co.uk/report/resources_task_intro.cfm
  9. Jan 7, 2005 #8


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    From my (admittedly limited) understanding of mega-tsunami, and especially those predicted from asteroid impact, the wave caused by this projectile would be much larger than the wave that would result from an earthquake of equal force. This is because the asteroid "tunnels" through the water down to the bottom, displacing large amounts of water and leaving empty space. This phenomenon has been verified in laboratory models and by evidence from sites where mega-tsunami have been generated by landslides.
    Last edited: Jan 8, 2005
  10. Jan 8, 2005 #9


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    You're probably right - the mechanism is different. I wish the site would say something about tsunamis.
  11. Jan 9, 2005 #10
  12. Jan 9, 2005 #11
    Many thanks, great paper.

    In the 'timline' graph, at time 40 seconds, the peak of splash appears to be vertically intact?..I would have thought the splash would have sent a volume of water that , excuse the wording 'takes-off'?

    I have seen experiment footage in a slowed-down manner of milk? droplets, that send liquid globules high into the air, a volume/globular of water that must come back down to Earth with an added splashdown effect?

    I presume that any dispersed liquid can only maintain its volume up to a certain 'globular' size?..so the macro effects would be more of a 'spray'?
    Last edited: Jan 9, 2005
  13. Jan 10, 2005 #12
    Hello WHP,

    Indeed, in the graph it just '' looks'' that the peak is vertically intact.
    However, the horizontally and vertically scales of the graph are not the same,
    that is, the horizontal scale is ± 1cm=8 km and the vertical scale is
    ± 1cm=4km.

    So in fact, when using equal scales, the figure should be stretched out twice in horizontal direction.
    But even then, looking at an amplitude of 2200 m,that's a very big wave!

    The same, and even much more,is the case in the figures on page 21 of the paper.
    The horizontal scale use here is ± 1cm=4.5 km and the vertical scale is ±1cm =1 km.
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