The diameter-frequency relations for craters on planets and satellites.

The diameter-frequency relations for craters on Mars and on Phobos háve been derived and compared with those relations for craters on tne Moon, Mercury and the Earth.О распределении кратеров на поверхности планет и спутников.Определены распреде ления кратеров на поверхности Марса и Фобоса.Эти зависимости сравнены с аналогичными распределениями кратеров на поверхности Луны, Меркурия и Земли.Autoři odvodili závislosti počtu kráterů na jejich průměru na jednotku plochy pro Mars a Phobos a tyto závislosti porovnávali s obdobnými závislostmi pro krátery na Měsíci, na Merkuru a na Zemi.The study of the diameter-frequency relations for craters on the surfaces of plan ets and its satellites may be, according to some authors, very important for solving some questions concerning the origin and the age of these features.In the recent years, many authors have derived the diameter-frequency relations for craters on the Moon (e. g-[-L [2]) ^d some authors have also studied this relations for craters on Mars (e. g. [3], [4]) and on Mercury [5].The present authors investigated the diameter-frequency relation for craters on Mars using the Mariner 9 Mars Map.This map was prepared in cooperation with the Jet Propulsion Laboratory, the C!alifornia Institute of Technology, and the National Aeronautics and Space Administration (1972).It is, up to date, the best map of the surface of Mars.Craters on three different regions on this map were chosen for the investigation, as shown in Table 1.Fig. 1 shows the relations of incremental craters (N) vs. diameter *) 150 00 Praha 5, Švédská 8, Czechoslovakia