Maybe via: https://en.wikipedia.org/wiki/Turbidity_current https://en.wikipedia.org/wiki/Turbidity_current https://en.wikipedia.org/wiki/Submarine_canyon http

Maybe via: https://en.wikipedia.org/wiki/Turbidity_current https://en.wikipedia.org/wiki/Turbidity_current https://en.wikipedia.org/wiki/Submarine_canyon https://en.wikipedia.org/wiki/Submarine_canyon If you look at google maps on ocean floor near any major river you'll see it continue for hundreds of km. Longest is 2400km in bay of bengal.