How far can you hear the KABOOM--help please...

Discussion in 'Alternate History Discussion: After 1900' started by NHBL, Aug 29, 2011.

  1. NHBL Member

    Joined:
    Jan 1, 2004
    I'm working on an ATL with some big (near nuclear and nuclear) level explosions. Finding things like destruction radius is easy--but I'm hunting for things like how far away a blast could be heard, how far away it could be felt, and minor effects like broken windows. THAT is hard to find. The blast occurs in time of peace, whith no one even expecting an earth-shattering KABOOM--or even knowing that there's a way to make a KABOOM that big.

    Things like how far away it's heard will be important to the timeline; I just need a reasonable ballpark figure. (Atmosphereics and mountains and the like will have some influence.)

    Thanks!
     
  2. Peabody-Martini Well-Known Member

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    Aug 23, 2010
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    Portland, Oregon
    For what's possible, the 1883 eruption of Krakatoa was reported to have been heard 3,000 miles (4,800 km) away. Said to be 310 decibels.

    As for nukes, the overpressure wave is around 250 to 280 decibels.

    Does that help?
     
  3. NHBL Member

    Joined:
    Jan 1, 2004
    40 Kilotons

    Doesn't the overpressure wave depend on how big the nuke is? I'm thinking "nuke" because we have real world experience with them, and not with big meteorite impacts. The rock is going to create about a 400 KT blast, and how far it's heard is important, as is the broken window effect.

    This is no Krakatoa, but also no mere "pop"
     
  4. Cook Real friends stab you in the front.

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    In 1917 the British Army detonated 19 mines along the Western Front. The charge under Hill 60 in Belgium was 53,500 pounds, nearly 27 tons of high explosive. When they went off they were heard in London, and there are reports that the tremor was felt in Dublin.
     
  5. Peabody-Martini Well-Known Member

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    Location:
    Portland, Oregon
    The size of the explosion you described could probably be heard for hundreds of miles. Depending on if its an airburst, surface or underground detonation.

    Or as the saying goes "Even a small nuke will ruin your day".
     
  6. Cook Real friends stab you in the front.

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    Found it:


    http://allshookup.org/quakes/atomic.htm
     
  7. NHBL Member

    Joined:
    Jan 1, 2004
    Specifics:

    It's not a nuke, but a meteorite. It lands in the White Mountains of New Hampshire, some 60+ miles north of Concord, NH, with an impact similar to the detonation of a 400 KT bomb. Will it break windows in Concord? Can they hear it in Boston, about 120 miles away? Or Providece, 170 or so miles away?

    New York City?

    I'd assume that it's a very noticable BOOM in Concord--a clear "This is BAD" sort of boom. But--hopw noticable in Boston?
     
  8. Mad Bad Rabbit Well-Known Member

    Joined:
    Aug 18, 2007
    There is an online calculator at http://impact.ese.ic.ac.uk/ImpactEffects/ for that very thing:

    Working backwards from a 400 KT blast, this would be the same energy as a stony iron asteroid 8.5 meters wide striking Earth at 20 km/s. It would not reach the surface (or even the lower atmosphere), and the airburst would not produce any damage in Concord; it would barely be audible even at ground zero.

    It would need to be at least 250 meters wide (1000 megaton yield) to shatter windows in Concord and to be audible in Boston and Providence.