The terrestrial cratering record. II - The crater production rate

The terrestrial crater production rate is estimated from a compilation of the locations and ages of proven and probable terrestrial impact craters and compared with that calculated from astronomical observations and for other planets. The estimated size-frequency distribution of craters greater than 20 km in diameter formed during the Phanerozoic, a -2 power law, is similar to the distributions of lunar and Martian craters. The North American and East European cratons are estimated to have cratering rates of craters greater than 20 km of 0.36 x 10 to the -14/sq km yr and 0.33 x 10 to the -14/sq km yr, respectively, in good agreement with previous estimates and observations of Apollo bodies. Comparisons with the lunar rate indicate that the lunar and terrestrial rates overlap if the cratering flux had been constant over the last 3.4 billion years, however if a constant rate was not reached until 3.0 to 2.5 billion years ago, the lunar rate would have been half that of the terrestrial rate.