Ocean Floor Map

Markham Canyon map

Submarine canyon: 327 m down (GEBCO_2026 grid).

Tap or scroll to load the interactive map

Sea level todayDrag the slider to lower the sea and see the land that would appear.

Sea level in metres below today’s. A simple bathtub model: it lowers the sea everywhere by the same amount and does not simulate how the water would really drain.

Key

Sea depth

  • Deeper than 6,000 m
  • 4,000 to 6,000 m
  • 2,000 to 4,000 m
  • 1,000 to 2,000 m
  • 200 to 1,000 m
  • Shallower than 200 m (the continental shelf)

Land height

  • Land up to 500 m
  • 500 to 2,000 m
  • Above 2,000 m

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  • Seabed exposed when the sea is lowered A dashed white line marks today’s coast.

How to read the map. Darker blue is deeper water. Tap anywhere to see how deep the sea is there, or how high the land is, and the nearest named undersea feature. Depths come from the GEBCO_2026 grid, which in most of the deep ocean is predicted from satellite measurements of the sea surface rather than surveyed by ship, and the map’s tiles are coarser than the grid, so narrow trenches read shallower on the map than their true depth. Not for navigation.

Markham Canyon at a glance

  • 327 mdeep in the grid
  • Submarine canyontype of feature
  • 6.75° S, 147.00° Elisted point
  • Papua New Guineanearest country, about 1 km
  • 155 of 173deepest of the submarine canyons in our list

Markham Canyon is a submarine canyon. In the GEBCO grid it reaches 327 m below sea level. That figure is the depth in the grid at its listed centre point, so a typical depth for the feature, not its deepest or shallowest point. The nearest country in our list is Papua New Guinea, about 1 km from its listed point.

Open the main map at its listed point and tap anywhere to read the depth.

How deep is the Markham Canyon?

The grid figure is 327 m. We measured it as the depth in the grid at its listed centre point, so a typical depth for the feature, not its deepest or shallowest point. The GEBCO_2026 grid has a value every 15 arc-seconds, about 460 m at the equator, so a very narrow feature can be a little deeper or shallower in reality than any grid cell shows.

Wikidata has no depth figure for this feature, so the grid is our only source for it.

Among the 173 submarine canyons in our list it ranks 155th by depth. The list is the named features on Wikidata with a position at sea, so it is not every submarine canyon in the world.

About submarine canyons

Submarine canyons are steep valleys cut into the continental slope, often by rivers of sediment-laden water that flow downhill under the sea.

This site lists 173 submarine canyons, 27 of them with their own indexed page. See all undersea features.

Nearby undersea features

Distances are between listed points. A long feature such as a trench or ridge has a single listed point on Wikidata.

The deepest submarine canyons in our list

Frequently asked questions

How deep is the Markham Canyon?

In the GEBCO grid the figure is 327 m. That is the depth in the grid at its listed centre point, so a typical depth for the feature, not its deepest or shallowest point.

Where is the Markham Canyon?

Its listed point is 6.75° S, 147.00° E, about 1 km from Papua New Guinea.

Data: depth from the GEBCO_2026 grid. Name and position from Wikidata Q34766308 (CC0). See data sources and licences. The GEBCO Grid should NOT be used for navigation or for any other purpose involving safety at sea.

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