Submarine channel

Depth of water

Shelf edge - Abyssal plain (120 - 5,000 m)

Circumstances

Trenches at the downstream of submarine canyons. Submarine channels are several meters to several hundreds of meters width, several tens of meters to 2 km depth, and are very long from the continental shelf edges to the bottom of forearc basins or the abyssal plain. Submarine channels and submarine levees are a part of Channel-Levee complexes which form submarine fan at the lower part of the continental slope. Sediments from the continental shelf flow as sediment gravity flows (turbidity currents) when an earthquake happens. Turbidity currents pass intermittently, typically once every a few hundreds years. Fine sediments deposit during intervals. Pyroclastic flows deposited as turbidite is called as pyroturbidite.

Sedimentary facies (Sediments)

Debris flow deposits. Conglomerates with a matrix of poorly-sorted sands and mud.

Sedimentary facies (Structures)

Trough cross -stratifications. Trough-shaped channels are filled with sands having thin foliations, and each channel is cut by other channels.