The continental slope is the steep part of the seabed that falls away from the edge of the continental shelf towards the deep ocean. It marks the real edge of the continent and is often cut by submarine canyons.
Key takeaways
- The slope begins at the shelf break and is the steepest part of the continental margin.
- On average it drops at about 3 degrees, which is gentle by mountain standards but steep for the seabed.
- Submarine canyons often cut into the slope and carry sediment down to the deep ocean.
- In our grid, the Atlantic Ocean has a mean depth of 3,883 m, reached mostly by going down slopes like this.
How the continental slope works
Moving out from a coast, the seabed first runs across the shallow continental shelf. At the shelf break the ground steepens, and that steeper stretch is the continental slope [1]. The slope is where the continent finally gives out and the seabed drops down towards the deep ocean.
Its average angle is about 3 degrees, with a range from around 1 to 10 degrees [1]. That sounds small, but it carries the seabed down over a vertical distance of thousands of metres.
The slope is not smooth. Submarine canyons often cut into it [1]. Mud and sand that have built up on the shelf slump and flow down these canyons in fast, dense currents of sediment-laden water, called turbidity currents. At the bottom, the sediment spreads out and builds the continental rise, which is a gentler apron at the foot of the slope [1].
On our map, you will see the slope as a tight band where the depth colours change quickly along a coastline. The map does not draw a separate layer for the slope, so it shows up through the colour ramp and the shading.
An example from our data
The slope is easy to spot where the sea gets deep fast. The Atlantic Ocean has a mean depth of 3,883 m, but only 5.1% of it is shallower than 200 m. Nearly all of the rest has been reached by going down a slope.
One feature cut into a slope is the Congo Canyon, which our grid places 58 km from Angola. You can find more on the features page, where we list 173 canyons among the 950 named features.
Compare the Pacific Ocean. Its mean depth is 4,315 m, and the slope there is often followed immediately by a trench, such as the Peru Chile Trench, at 8,243 m, only 45 km from Chile.
The thing people get wrong
The word "slope" suggests a cliff, and diagrams of the ocean floor often stretch the vertical scale to make it look like one. In reality the average angle is about 3 degrees [1]. It only looks dramatic because it descends such a long way.
People also mix up the slope with the rise. The slope is the steep stretch just past the shelf. The rise is the gentler, sediment-built apron below it, which merges into the abyssal plain [1][2]. The two are separate parts of the continental margin, and they have different gradients.
Frequently asked questions
How steep is the continental slope?
Its average angle is about 3 degrees, ranging from around 1 to 10 degrees. That is steep for the seabed, but it is much gentler than a mountainside.
What is the difference between the shelf and the slope?
The shelf is shallow and gently sloping. The slope starts at the shelf break and drops much more steeply into deep water.
Sources
- Continental shelf, Wikipedia.
- Abyssal plain, Wikipedia.
- Every figure from our own map is worked out from the datasets on the data sources page (checked against GEBCO_2026 grid).