By the end of the 1970s, 120 impact structures had been identified in various parts of the world and a suite of characteristic rock forms common to many craters had been described.
Mafheloni a nwaha wa 1970, ha vha na zwivhumbeo zwo no swika 120 zwo wanalaho kha fhethu hune ha vha uri ho fhambana kha shango ha kona u wana mvumbo dza matombo o sikaho dzi craters dzo fhambanaho a kona u wanala.