The Cumbre Vieja Ridge is the volcanic spine of La Palma and, in the novel, a potential source of cascading disaster. Its significance lies in the connection drawn between the island’s volcanic structure, methane hydrates beneath the adjacent seabed, and the possibility that a submarine slide could help detach the ridge’s western flank. The feared collapse remains a forecast, not an event that the evidence establishes as having occurred.

Setting and geological structure

The ridge extends south from the Caldera de Taburiente, an immense erosion crater in the north, as a line of volcanic cones toward the island’s southern tip. La Palma rises steeply from deep water: the Canary Islands’ volcanic peaks emerge from seabed depths of roughly 3,000 to 3,500 metres. The ridge is not a single smooth face but part of a volcanic landscape shaped by eruptions, with terraces and irregularities that matter to the story’s account of what may lie offshore.

The setting’s apparent beauty offers no guarantee of stability. La Palma’s long intervals between eruptions do not rule out renewed activity; in 1971, the Teneguia volcano erupted near the island’s southern tip and added several hectares to the landmass. The ridge is described as one volcano with numerous vents, a structure that makes local changes relevant to the wider volcanic system.

The offshore investigation

Stanley Frost argues that conventional charts may have missed methane hydrates around the Canary Islands because they were assumed to have steep, smooth slopes where sediment could not accumulate. In his account, the volcanic seamounts have ridges and terraces; sediment can settle there, and hydrates may run through the rock in thin veins rather than appearing in large deposits on the seabed. He considers this a consequential gap in earlier assumptions about the region.

Frost identifies La Palma as the greatest threat among several volcanic islands he considers potentially at risk, including Hawaii, Cape Verde, Tristan da Cunha, and Reunion. With help from Gerhard Bohrmann, his team receives the research vessel Polarstern and deploys its Victor 6000 off the island’s western coast. At a depth of 400 metres, the robot finds overlapping terraces jutting from the rock and covered in sediment. The observation supports the proposed terrain on which hydrates might occur; it does not, by itself, establish that a catastrophic collapse is inevitable.

A proposed chain of failure

Frost links the ridge’s vulnerability to an earlier eruption. In 1949, an eruption from a crater near the top of the San Juan volcano opened a fault running for kilometres along the western flank. A section of the ridge then slipped about four metres toward the sea. Frost says that the flank may be fissured and that the eastern and southern sides press against it. He also points to unusually large quantities of groundwater trapped in the rock as a factor that could increase instability during a future eruption.

In the projected volcanic scenario, new magma entering a vent would rapidly heat and expand the groundwater, adding pressure that could blast the western flank into the ocean. Frost estimates that around 500 cubic kilometres of rock could collapse. He also describes a second route: worms working on an underwater avalanche could detach part of the volcano, producing a smaller earthquake that might in turn trigger an eruption or further destabilize the ridge. In this account, submarine activity and volcanic instability are not separate hazards but possible links in the same sequence.

Scale of the threatened consequences

Frost warns that a wave of about 50 metres would be enough to flatten New York and that its impact would release more energy than the United States uses in a year. These are projections used to communicate the possible scale of the disaster, not descriptions of a wave that has struck. He presents the underwater avalanche and a future eruption as alternative pathways toward detachment, and argues that the worm activity could make the process faster than the weeks taken by the worms off Norway to complete their work there.

The ridge therefore gives the novel a precise geographical focus for a much wider problem: uncertainty about the seabed can intersect with a known geological weakness, while one disturbance may amplify another. La Palma’s volcanic history makes the threat legible, but the proposed chain—from hydrates and worms to seabed failure, earthquake, and possible flank collapse—remains a feared scenario whose consequences would reach far beyond the island.