Which seafloor feature is a circular or elliptical projection rising more than 1 kilometer with a steep slope?

• A. Guyot
• B. Island Arc
• C. Shelf Break
• D. Seamount

Answer: (D)

Rising underwater mountains formed by volcanic activity are called seamounts. Their shape is usually circular or elliptical when viewed from above, and they stand more than a kilometer above the surrounding seafloor with steep slopes up to the summit. That steep, conical relief is the key clue here. A flat-topped seamount, known as a guyot, has had its peak eroded to a plateau, which won’t have the same steep sides. An island arc is a chain of volcanic islands formed at subduction zones, not a single undersea mountain with prominent steep slopes. A shelf break is simply the boundary between the continental shelf and the continental slope, not a mountainous projection. So the feature described fits a seamount.