They had travelled to the Lomonosov ridge, an underwater shelf in Russia's remote and inhospitable eastern Arctic Ocean.

Some scientists speculate that the methane gas pockets in the underwater shelves could cause undersea landslides that might produce tsunamis.

There are oil and gas fields in the underwater shelf around the island, which are among the largest in Indonesia.

Tattenham Ledge, a long shallow underwater shelf of rock, extends from the northern side of the island and is a hazard to navigation.

Xabbu scrambled out, but the river was surprisingly shallow; Renie decided they had crashed on the edge of a sandbar or some other kind of underwater shelf.

The villagers, whose heads could be seen bobbing about in the distance, had reached the edge of the underwater shelf.

Its success would turn near-surface submarine shelves like this one into prime candidates for life, abundant life like the coral colonies that populated the underwater shelves of Earth.

The underwater shelf of the coastline dropped off abruptly after a few more feet; she knew when she passed the place by the deeper hue and colder water.

Jack saves Steve's life but is lost when the Southern Cross slips off the underwater shelf into deep water.

Thetis joins him as he reaches the underwater shelf where the depths begin.