Meteorite

Just out of interest, how big a meteorite would be
needed to cause a equivalent tsunami to the one in
south east Asia ? Not an easy question I guess.

H.

Probably depends on speed at impact since E=0.5mv^2.

We need to know the energy that the quake dumped into the ocean
as the tsunami.


Martin
--
M.A.Poyser Tel.: 07967 110890
Manchester, U.K. http://www.fleetie.demon.co.uk

On Sun, 2 Jan 2005 17:19:56 -0000, "howard" wrote:

| Just out of interest, how big a meteorite would be
| needed to cause a equivalent tsunami to the one in
| south east Asia ? Not an easy question I guess.
|

Not a simple comparison as you say.
The Asian tsunami was caused by a relatively slow (several seconds)
slumping of the ocean floor.
A large meteorite hits at one hell of a speed.
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Dave Fawthrop
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In message , Fleetie
writes
Probably depends on speed at impact since E=0.5mv^2.

We need to know the energy that the quake dumped into the ocean
as the tsunami.


Martin

Howard asked how big a meteorite would be needed to create a tsunami
like the one in Asia (hint: quoting is useful)
I don't know how much energy goes into the wave, but the total energy of
a Richter 9 earthquake is about 10^25 ergs, which is the same as the
kinetic energy of a 250 meter rock moving at 50 km/s. Again, I don't
know how much energy would go into the wave if it hit in deep water.
As you'd expect, there's a lot about this on the Web, and
http://www1.tpgi.com.au/users/tps-seti/spacegd7.html#tsunamiimpact
looks interesting.
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"Jonathan Silverlight"
Howard asked how big a meteorite would be needed to create a tsunami like the one in Asia (hint: quoting is useful)

The question "How big ... ?" is invalid as it stands.

You need to specify at least density and closing speed, as well as
whether the size referred to that before encountering the atmosphere
and having possibly large amounts of the meterorite burnt off, or
whether it was the size at impact having travelled through the
atmosphere, and probably other variables too.


Martin
--
M.A.Poyser Tel.: 07967 110890
Manchester, U.K. http://www.fleetie.demon.co.uk

In message , Dave Fawthrop
writes
On Sun, 2 Jan 2005 17:19:56 -0000, "howard" wrote:

| Just out of interest, how big a meteorite would be
| needed to cause a equivalent tsunami to the one in
| south east Asia ? Not an easy question I guess.
|

Not a simple comparison as you say.
The Asian tsunami was caused by a relatively slow (several seconds)
slumping of the ocean floor.
A large meteorite hits at one hell of a speed.

Http://www.lpl.arizona.edu/impacteffects/

There's a Javascript program here for the enthusiasts.


Have fun

Brian
--
Brian Howie

In message , Kitty writes


Ive heard the power generated by the earthquake was compared to
"1,000 Hiroshima's" Is this a realistic guess, or just media fodder ?

It's actually a gross understatement. The figure is closer to a million
Hiroshimas, 32 thousand million tons of TNT.
Another useful web site is
http://www.seismo.unr.edu/ftp/pub/louie/class/100/magnitude.html,
which has a really boggling fact - the Earth receives 1000 x that energy
as sunlight every day. Suitably applied, it would split the planet.


I would have thought wave size was simply proportional to the volume
of displacement of water by a meteorite ?

It's more complicated than that in shallow water, which is where people
get hurt. But the problem is working out how much water is displaced in
the first place. There are figures for atomic and other explosions, but
extrapolation is always dodgy.