Lunar and Planetary Laboratory, Department of Planetary Sciences, University of Arizona, Tucson, AZ 85721-0092, United States; Planetary Science Institute, 1700 E. Fort Lowell, Tucson, AZ 85719-2395, United States; Department of Earth Science and Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom; Impact Cratering Research Group, School of Geosciences, University of the Witwatersrand, Private Bag 3, Wits 2050, Johannesburg, South Africa; Canadian Space Agency, 6767 Route de l'Aeroport, Saint-Hubert, QC J3Y 8Y9, Canada
Turtle, E.P., Lunar and Planetary Laboratory, Department of Planetary Sciences, University of Arizona, Tucson, AZ 85721-0092, United States, Planetary Science Institute, 1700 E. Fort Lowell, Tucson, AZ 85719-2395, United States; Pierazzo, E., Planetary Science Institute, 1700 E. Fort Lowell, Tucson, AZ 85719-2395, United States; Collins, G.S., Lunar and Planetary Laboratory, Department of Planetary Sciences, University of Arizona, Tucson, AZ 85721-0092, United States, Department of Earth Science and Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom; Osinski, G.R., Lunar and Planetary Laboratory, Department of Planetary Sciences, University of Arizona, Tucson, AZ 85721-0092, United States, Planetary Science Institute, 1700 E. Fort Lowell, Tucson, AZ 85719-2395, United States, Canadian Space Agency, 6767 Route de l'Aeroport, Saint-Hubert, QC J3Y 8Y9, Canada; Melosh, H.J., Lunar and Planetary Laboratory, Department of Planetary Sciences, University of Arizona, Tucson, AZ 85721-0092, United States; Morgan, J.V., Department of Earth Science and Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom; Reimold, W.U., Impact Cratering Research Group, School of Geosciences, University of the Witwatersrand, Private Bag 3, Wits 2050, Johannesburg, South Africa
The diameter of an impact crater is one of the most basic and important parameters used in energy scaling and numerical modeling of the cratering process. However, within the impact and geological communities and literature, there is considerable confusion about crater sizes due to the occurrence of a variety of concentric features, any of which might be interpreted as defining a crater's diameter. The disparate types of data available for different craters make the use of consistent metrics difficult, especially when comparing terrestrial to extraterrestrial craters. Furthermore, assessment of the diameters of terrestrial craters can be greatly complicated due to post-impact modification by erosion and tectonic activity. We analyze the terminology used to describe crater geometry and size and attempt to clarify the confusion over what exactly the term "crater diameter" means, proposing a consistent terminology to help avert future ambiguities. We discuss several issues of crater-size in the context of four large terrestrial examples for which crater diameters have been disputed (Chicxulub, Sudbury, Vredefort, and Chesapeake Bay) with the aim of moving toward consistent application of terminology. © 2005 Geological Society of America.