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EspañolCUMBRE VIEJA
'Cumbre Vieja' (Spanish: "Old Summit") is a volcanic ridge on the island of La Palma in Spain's Canary Islands.
This ridge extends roughly in a north-south direction and covers the southern third of the island. It is lined by several volcanic craters. Location: .
La Palma is not only the steepest island in the world but has also been the most volcanically active of the Canary Isles in the past 500 years. The last few eruptions in the ridge were in 1470, 1585, 1646, 1677, 1712, 1949, and 1971.
During the 1949 eruption, a two kilometer-long fracture opened and parts of the western half of the Cumbre Vieja ridge slipped several meters downwards towards the Atlantic Ocean. The fracture can quite easily be seen to this day. It is believed that this process was driven by the pressure caused by the rising magma heating and vaporizing water trapped within the structure of the island.
Scientists warn of the likelihood that together with one of the next five eruptions, to take place anywhere from the immediate future to several centuries from now, the western half of the island - approximately 500km³ of land weighing an estimated 500 billion metric tons - will be triggered to slide with monumental force towards the ocean floor along a west-northwesterly course - a so-called "lateral collapse". When that happens, the resulting megatsunami would reach local heights of over 900 meters and the speed of a jetliner, attaining the African coast in three hours, the coast of England in five, and the eastern seaboard of North America in eight, by which time it's believed the one original wave could have degenerated into a succession of smaller ones, numbering perhaps a dozen or so, all 100-200 feet high and 1-2km thick but retaining their original speed while striking at rough 20- to 30-minute intervals. This would greatly damage if not completely destroy cities along the entire United States' east coast, such as Boston, New York, Philadelphia, Baltimore, Washington, D.C., Norfolk, Charleston, Savannah and Miami, not to mention a long list of other small to medium-sized cities and towns, no doubt causing massive and lasting economic damage in consequence. It is observed that, over the last several thousand years, the distribution and orientation of vents and feeder dykes within the mountain have shifted from a triple rift system (typical of most oceanic island volcanoes) to one consisting of a single north-south rift with westward-extending vent arrays. Some argue that these structural reorganizations are in response to evolving stress patterns associated with the growth of a detachment fault under the volcano's west flank.[1]
There is controversy, however, about the seriousness of the threat at Cumbre Vieja, with indications that recent landslides there have been gradual, and as such might not generate tsunamis even if they escalated to a larger scale. Others, who have studied localized megatsunami in the Hawaiian Islands, draw distinctions between the tsunami wave periods caused by landslides and subduction-zone earthquakes, arguing that a similar collapse in Hawaii would not endanger Asian or North American coastlines.[2]
History has also documented large and damaging tsunamis from far smaller lateral collapses of stratovolcanos and residual debris found on the seafloor does provide evidence of their abundance in recent geological time (see Storegga Slide). In recorded history, the Krakatoa and Santorini eruptions have generated devastating and deadly tsunamis, yet the damage was local and did not propagate across long distances. An earthquake and landslide in Crillon Inlet at the head of Lituya Bay, Alaska, on July 10, 1958 generated a monstrous megatsunami 524 m (1740ft) high, which stripped trees and soil from the opposite headland and consumed the entire bay, destroying three fishing boats anchored there and killing two people. Once the wave reached the open sea, however, it dissipated quickly.
As of 2004, there is very little seismological monitoring of Cumbre Vieja in progress.
Patrick Robinson, in 2004, wrote a fictional techno-thriller ''Scimitar SL-2'' outlining a plot to destroy Cumbre Vieja with nuclear warheads, thereby creating massive tsunamis.
1. http://www.es.ucsc.edu/~ward/papers/La_Palma_grl.pdf
2. http://www.mala.bc.ca/~earles/kohala-tsunami-sep04.htm
★ Discussion
★ Benfield Hazard Research Center: Why the only certainty about the La Palma tsunami is that it ''will'' happen
★ Benfield HRC Q&A
★ Pictures of Cumbre Vieja
★ A rebuttal of Cumbre Vieja
★ Another rebuttal of the possible disaster
★ CNN: Scientists warn of massive wave
★ BBC: Expert says threat is being ignored.
★ BBC: Threat is stated to be a worse case scenario; it ''might'' not happen.
This ridge extends roughly in a north-south direction and covers the southern third of the island. It is lined by several volcanic craters. Location: .
| Contents |
| Volcanic history |
| 1949 eruption |
| Future threat |
| Notes |
| External links |
| Information and sources |
| Press articles |
Volcanic history
La Palma is not only the steepest island in the world but has also been the most volcanically active of the Canary Isles in the past 500 years. The last few eruptions in the ridge were in 1470, 1585, 1646, 1677, 1712, 1949, and 1971.
1949 eruption
During the 1949 eruption, a two kilometer-long fracture opened and parts of the western half of the Cumbre Vieja ridge slipped several meters downwards towards the Atlantic Ocean. The fracture can quite easily be seen to this day. It is believed that this process was driven by the pressure caused by the rising magma heating and vaporizing water trapped within the structure of the island.
Future threat
Scientists warn of the likelihood that together with one of the next five eruptions, to take place anywhere from the immediate future to several centuries from now, the western half of the island - approximately 500km³ of land weighing an estimated 500 billion metric tons - will be triggered to slide with monumental force towards the ocean floor along a west-northwesterly course - a so-called "lateral collapse". When that happens, the resulting megatsunami would reach local heights of over 900 meters and the speed of a jetliner, attaining the African coast in three hours, the coast of England in five, and the eastern seaboard of North America in eight, by which time it's believed the one original wave could have degenerated into a succession of smaller ones, numbering perhaps a dozen or so, all 100-200 feet high and 1-2km thick but retaining their original speed while striking at rough 20- to 30-minute intervals. This would greatly damage if not completely destroy cities along the entire United States' east coast, such as Boston, New York, Philadelphia, Baltimore, Washington, D.C., Norfolk, Charleston, Savannah and Miami, not to mention a long list of other small to medium-sized cities and towns, no doubt causing massive and lasting economic damage in consequence. It is observed that, over the last several thousand years, the distribution and orientation of vents and feeder dykes within the mountain have shifted from a triple rift system (typical of most oceanic island volcanoes) to one consisting of a single north-south rift with westward-extending vent arrays. Some argue that these structural reorganizations are in response to evolving stress patterns associated with the growth of a detachment fault under the volcano's west flank.[1]
There is controversy, however, about the seriousness of the threat at Cumbre Vieja, with indications that recent landslides there have been gradual, and as such might not generate tsunamis even if they escalated to a larger scale. Others, who have studied localized megatsunami in the Hawaiian Islands, draw distinctions between the tsunami wave periods caused by landslides and subduction-zone earthquakes, arguing that a similar collapse in Hawaii would not endanger Asian or North American coastlines.[2]
History has also documented large and damaging tsunamis from far smaller lateral collapses of stratovolcanos and residual debris found on the seafloor does provide evidence of their abundance in recent geological time (see Storegga Slide). In recorded history, the Krakatoa and Santorini eruptions have generated devastating and deadly tsunamis, yet the damage was local and did not propagate across long distances. An earthquake and landslide in Crillon Inlet at the head of Lituya Bay, Alaska, on July 10, 1958 generated a monstrous megatsunami 524 m (1740ft) high, which stripped trees and soil from the opposite headland and consumed the entire bay, destroying three fishing boats anchored there and killing two people. Once the wave reached the open sea, however, it dissipated quickly.
As of 2004, there is very little seismological monitoring of Cumbre Vieja in progress.
Patrick Robinson, in 2004, wrote a fictional techno-thriller ''Scimitar SL-2'' outlining a plot to destroy Cumbre Vieja with nuclear warheads, thereby creating massive tsunamis.
Notes
1. http://www.es.ucsc.edu/~ward/papers/La_Palma_grl.pdf
2. http://www.mala.bc.ca/~earles/kohala-tsunami-sep04.htm
External links
Information and sources
★ Discussion
★ Benfield Hazard Research Center: Why the only certainty about the La Palma tsunami is that it ''will'' happen
★ Benfield HRC Q&A
★ Pictures of Cumbre Vieja
★ A rebuttal of Cumbre Vieja
★ Another rebuttal of the possible disaster
Press articles
★ CNN: Scientists warn of massive wave
★ BBC: Expert says threat is being ignored.
★ BBC: Threat is stated to be a worse case scenario; it ''might'' not happen.
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