| S. No. | Abyssal plain | Ocean deeps |
| (i) | Abyssal plains are under water plains found on the deep ocean floor | These are the deepest part of the oceans. |
| (ii) | These plains extend from continental rise to the midoceanic ridges. | Trenches are the deepest part of the oceans. They occupy about 7% of the total relief of the ocean flour. |
| (iii) | Abyssal plains are usually covered by the thick layer of sediments composed of clay, silt and sand. | These are sediment free. So most trenches are Vshaped with steep sides. |
| (iv) | Abyssal hills, sea mounts, guyots,coral atoll, etc., are the characteristic features. | Epicentre of the great earthquakes is all found in the trenches. |
