[meteorite-list] Earth Impactors

[Matson, Robert]

Hi Walter,   The biggest unknown to your question is how wide is your "wide destruction zone?" Are we talking city blocks, small cities, large cities or small countries?  Going with large cities, I'd put my WAG at somewhere between 200 and 500 meters in diameter, depending on material type.  For example, wasn't the iron that created Meteor Crater estimated to be about 150 meters in diameter?  Scaling up to 200 meters diameter more than doubles the energy of the impact -- enough I would think to wipe out a large metropolitan area.  --Rob