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On Fri, 7 Jan 2000, Richard wrote:
> The Barringer Crater near Flagstaff, AZ is a simple crater (as compared
> to a complex crater such as the lunar crater Copernicus with central
> peaks and motled landscape on the inside crater rim.) However, I've
> noticed one thing that sets Barringer apart from all other craters, it
> exhibits a slightly square appearance. How is this possible?
You are right that the most often-published image of the Barringer Crater
makes the crater look somewhat squarish. However, there are pictures of
the crater available from space (check out
http://earth.jsc.nasa.gov/land.html and search for "CRATER"), and from
this vantage point the crater is virtually round. Upon close inspection,
it seems to me that the sqaure appearance is caused by varying heights of
the crater rim.
It is possible for meteorite craters to appear oblong if the meteor
strikes at an oblique angle. Also, the final shape of a crater depends
upon the geology of the surrounding area. For craters on the moon, the
geology is markedly more simple (mainly basaltic plains) than on the
Earth, where weather, sedimentation, and plate tectonics serve to distort
geologic features, and so the ground where a meteor strikes may be prone
to cracking and collapsing in preferred directions. Even so, most seteor
craters are virtually circular. [I am not an expert in meteor impacts,
and so I honestly do not know how geology might affect the appearance of a
crater.]
Thanks for writing!
Sincerely,
Kurtis Williams
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