Ravi Vallis
The Ravi Vallis outflow channel and neighboring deep depression at Aromatum Chaos, are thought to have been caused by volcano-ice interactions underneath the surface, which pierced an underground aquifer. This released large amounts of water, causing a catastrophic flood event, with an estimated speed of between 10 and 25 m s. The discharge rates from the Ravi Vallis outflow channel are thought to have ranged from a maximum of ~30 × 10 m s after the beginning of the flood event, to below 10 × 10 m s in its later stages. The flood event is thought to have lasted between 2 and 10 weeks, with an estimated minimum total water volume of somewhere in the range of 11,000 to 65,000 km.
Intermittent volcanism and related flood events like that which occurred at Ravi Vallis, are known to have occurred in other regions of Mars, such as at Kasei Valles, and Mangala Valles.