Isolated mountain of volcanic origin featuring a pointed summit.
trench
Extremely deep elongated depression bordering a continent or island arc; it occurs when one tectonic plate moves under another.
volcanic island
Volcano whose summit rises above sea level.
island arc
String of volcanic islands formed when two tectonic plates meet.
abyssal hill
Rounded underwater rise of low elevation.
sea level
Mean water level observed for a given duration (day, month, year); it is used as a reference to define coastal features and calculate the elevation of topographical elements.
mid-ocean ridge
Group of underwater mountain chains criss-crossing the oceans; it is formed by an outpouring of magma.
continent
A collective term for the vast landmasses and their submerged margins.
submarine canyon
Deep valley that is frequently the extension of a river; it ends in a sediment buildup.
continental slope
Slope of a few degrees that extends from the continental shelf; it is 200 to 2,000 meters deep.
continental rise
Gently sloping section of the continental margin; it connects the continental slope to the abyssal plain.
abyssal plain
Zone located at a depth of 2,000 to 6,000 meters; it covers most of the ocean floor.
