Magnitude of a catastrophic flood event at Kasei Valles, Mars

Kasei Valles compose an enormous outflow-channel system on Mars. The upper part of the channel system is typically < 1 km deep and descends from Echus Chasma about 1 km over a distance of 1000 km; it then splits into north and south Channels. On the basis of a stereomodel of Viking images, we have measured the geometry of a steep, constricted reach of the north channel that drops 900 m in only 100 km. A late-stage flood is hypothesized to have scoured the channel. If we assume that channel striations indicate water levels, then the flood had a minimum cross-section area of 3.12 × 10 ⁷ m ² . These channel measurements suggest that flood velocities ranged from 32 to 75 m.s ^-1 and that discharge was > 1 km ³ .s ^-1 , values larger than those calculated for any other flood event on Mars or Earth. -from Authors