Crater Morphology

Craters can take on a lot of different shapes and, to make it easier to talk about them and to analyze them, scientists have developed a set of keywords and codes.  In this post, we'll go through some of the common ones (and by "common," I mean the ones I'm looking at in my analysis):

• SLE (Single-Layer Ejecta): Craters that have one layer of ejecta. 

A and B both show SLE craters. [1]

• DLE (Double-Layer Ejecta): Craters that have two superimposed layers of ejecta

C is a DLE crater.  Both layers are easily seen on the right side of the crater. [1]

• MLE (Multiple-Layer Ejecta): Craters that have more than two layers of ejecta.



Part of an MLE crater. [2]

• Pd (Pedestal):  Craters that have a raised layer of ejecta around them.  The ejecta makes it look like the crater is sitting on a pedestal.

The most perfect example ever of a pedestal crater [3]

• Rd (Radial): Craters whose ejecta make a radial pattern, like spokes on a wheel.

Poona, a radial crater [4]

References

 [1] Robbins, S.J. (2011) "Planetary Surface Properties, Cratering Physics, and the Volcanic History of Mars from a New Global Martian Crater Database" Ph.D. Thesis, University of Colorado at Boulder.

 [2] Barlow, Nadine G. "Impact craters in the northern hemisphere of Mars: Layered ejecta and central pit characteristics." Meteoritics & Planetary Science 41.10 (2006): 1425-1436.

 [3] "ESP 037528 2350pedestal" by Jim Secosky modified NASA image. - http://hirise.lpl.arizona.edu/ESP_037528_2350. Licensed under Public Domain via Commons - https://commons.wikimedia.org/wiki/File:ESP_037528_2350pedestal.jpg#/media/File:ESP_037528_2350pedestal.jpg

 [4] Mutch, Thomas A., et al. "The geology of Mars." Princeton, NJ, Princeton University Press, 1976. 409 p. 1 (1976).