Dear Benny:
I thought you and your subscribers might be interested in a new web
tool that I have been working on with Robert Marcus and Gareth Collins.
The tool is described in the U of Arizona  press release copied below.
The main purpose it to make it easy to estimate the basic effects of
an impact on the Earth, given the size and velocity of the projectile
and the distance you are located from it.  It is intended to be
accessible to high school students, but will also contain references
and expert descriptions of what it actually does (not yet
attached--Gareth Collins will do this in a week or two).  It presently
contains more elementary descriptions of the effects and a glossary.
I would appreciate any feedback from your subscribers on new features
to add, what you do/do not like about it, and especially if anyone
detects any serious errors!  By the way, we do *not* calculate tsunami
heights for oceanic impacts--that is presently too much of a can of
worms to handle, but maybe a future upgrade might deal with this.
The airblast effects are probably exaggerated for large impacts, as we
compute those straight out of the nuclear explosion literature and they
thus neglect the curvature of the Earth and the finite thickness of the
atmosphere.  We will be working on improving this in the months
Regards, Jay

Jay Melosh                                                           
Regents Professor of Planetary Science
University of Arizona
(from CCNet, 53/2004)