People thought the chatter on La Palma was over reacting or starting disinfo campaigns, I did too, and now there's an eruption. Wow.
Seems a bit angrier than the hawaiin volcano that took out huge swaths of real estate. (Due to geologic composition).
Primary worry is the landslide:
https://en.wikipedia.org/wiki/La_Palma
In a programme transmitted by the British Broadcasting Corporation BBC Horizon broadcast on 12 October 2000, two geologists (Day and McGuire) cited this crack as proof that half of the Cumbre Vieja had moved towards the Atlantic Ocean (Day et al.; 1999,[10] and Ward and Day, 2001[11]). They postulate that this process was driven by the pressure caused by the rising magma heating water trapped within the structure of the island. They hypothesised that during a future eruption, the western flank of the Cumbre Vieja, with a mass of approximately 1.5 x1015 kg, could slide into the ocean. This could then potentially generate a giant wave which they termed a "megatsunami" around 650–900 m (2,130–2,950 ft) high in the region of the islands. The wave would radiate out across the Atlantic and inundate much of the eastern seaboard of North America about 7 hours later, many of the islands in the Caribbean and northern coasts of South America between six and eight hours later. They estimate that the tsunami will have waves possibly 50 m (164 ft) or higher causing massive devastation along the coastlines. Modelling suggests that the tsunami could inundate up to 25 km (16 mi) inland – depending upon topography. The basis for Ward and Day (2001)[11] modelling the collapse of a much larger portion of the western flank than what the currently visible surface crack indicates as being potentially unstable, was based on geological mapping by Day et al.; (1999).[10] In this paper they argue that a large part of the western flank has been constructed in the scar of a previous collapse and therefore sits upon unstable debris.
However, nowhere in their paper do Ward and Day, (2001),[11] make any claim about the imminent collapse of the flank. They state that they have modelled the worst-case scenario, and as a result they state "a future collapse has the potential to cause a tsunami which may devastate the east coast of the USA and other locations".
The claim was also explored in a BBC docu-drama called End Day which went through several hypothetical scenarios of disastrous proportions.
In 2002 the Tsunami Society (Pararas-Carayannis, 2002[12]), published a statement stating "... We would like to halt the scaremongering from these unfounded reports..." The major points raised in this report include:
The claim that half of Cumbre Vieja dropped 4 m (13 ft) during the 1949 eruption is erroneous, and contradicted by physical evidence.
No evidence was sought or shown that there is a fault line separating a "block" of La Palma from the other half.
Physical evidence shows a 4 km (2 mi) long line in the rock, but the models assumed a 25 km (16 mi) line, for which no physical evidence was given. Further, there is no evidence shown that the 4 km (2 mi) long line extends beyond the surface.
There has never been an Atlantic megatsunami in recorded history.
See Fogo, Cape Verde for an example of a geologically recent Atlantic megatsunami.
A survey carried out by Moss et al.; (1999)[13] reported that the western flank is stable with no indication of aseismic creep being recorded.
In 2001 Carracedo et al.;[8] stated that they consider the 1949 crack to be a shallow and inactive surface expression. They do suggest that the crack should be monitored, but consider the possibility that the edifice is unstable as being almost non-existent.
Murty et al.; (2005)[14] claim that the morphology of the Atlantic Ocean prevents the generation and propagation of trans-oceanic tsunamis. However the Tohoku tsunami of 2011 propagated to Hawaii and the coast of California, a distance much greater than a trans-Atlantic crossing.
In 2006 professor Jan Nieuwenhuis of Delft University of Technology simulated several volcanic eruptions and calculated it would take another 10,000 years for the flanks to become sufficiently high and unstable to cause a massive collapse.,[15]
A 2008 paper looked into this very worst-case scenario, the most massive slide that could happen (though unlikely and probably impossible right now with the present day geology). They find wave heights in the range 10 to 188 meters in the Canary Isles themselves. But the waves interfere and dissipate as they head out into the Atlantic. They predict 40 meters height for some nearby island systems. For continents, the worst effects are in Northern Brazil (13.6 m), French Guyana (12.7 m), mid-US (9.6 m), Western Sahara (largest prediction at 37 meters) and Mauritania (9.7 m). This is not large enough to count as a megatsunami, with the highest prediction for Western Sahara comparable to the Japanese tsunami, so it would only be a megatsunami locally in the mid Atlantic.[16]
An underwater eruption that began in September 2011 south of the island of El Hierro gave rise to more speculation about the possibility of a megatsunami.[17][18] As each island in the archipelago is an independent edifice often several tens of kilometres away from the adjacent island it is geologically impossible that volcanic activity on one island will influence the other islands. El Hierro lies about 100 km south of La Palma, over 100 km south-west of Tenerife. La Gomera – extinct since about 4 million year BP, Gran Canaria and Fuerteventura no eruptive history since about 10000 years BY, Lanzarote last erupted in the 19th century.
In a programme transmitted by the British Broadcasting Corporation BBC Horizon broadcast on 12 October 2000, two geologists (Day and McGuire) cited this crack as proof that half of the Cumbre Vieja had moved towards the Atlantic Ocean (Day et al.; 1999,[10] and Ward and Day, 2001[11]). They postulate that this process was driven by the pressure caused by the rising magma heating water trapped within the structure of the island. They hypothesised that during a future eruption, the western flank of the Cumbre Vieja, with a mass of approximately 1.5 x1015 kg, could slide into the ocean. This could then potentially generate a giant wave which they termed a "megatsunami" around 650–900 m (2,130–2,950 ft) high in the region of the islands. The wave would radiate out across the Atlantic and inundate much of the eastern seaboard of North America about 7 hours later, many of the islands in the Caribbean and northern coasts of South America between six and eight hours later. They estimate that the tsunami will have waves possibly 50 m (164 ft) or higher causing massive devastation along the coastlines. Modelling suggests that the tsunami could inundate up to 25 km (16 mi) inland – depending upon topography. The basis for Ward and Day (2001)[11] modelling the collapse of a much larger portion of the western flank than what the currently visible surface crack indicates as being potentially unstable, was based on geological mapping by Day et al.; (1999).[10] In this paper they argue that a large part of the western flank has been constructed in the scar of a previous collapse and therefore sits upon unstable debris.
However, nowhere in their paper do Ward and Day, (2001),[11] make any claim about the imminent collapse of the flank. They state that they have modelled the worst-case scenario, and as a result they state "a future collapse has the potential to cause a tsunami which may devastate the east coast of the USA and other locations".
The claim was also explored in a BBC docu-drama called End Day which went through several hypothetical scenarios of disastrous proportions.
In 2002 the Tsunami Society (Pararas-Carayannis, 2002[12]), published a statement stating "... We would like to halt the scaremongering from these unfounded reports..." The major points raised in this report include:
The claim that half of Cumbre Vieja dropped 4 m (13 ft) during the 1949 eruption is erroneous, and contradicted by physical evidence.
No evidence was sought or shown that there is a fault line separating a "block" of La Palma from the other half.
Physical evidence shows a 4 km (2 mi) long line in the rock, but the models assumed a 25 km (16 mi) line, for which no physical evidence was given. Further, there is no evidence shown that the 4 km (2 mi) long line extends beyond the surface.
There has never been an Atlantic megatsunami in recorded history.
See Fogo, Cape Verde for an example of a geologically recent Atlantic megatsunami.
A survey carried out by Moss et al.; (1999)[13] reported that the western flank is stable with no indication of aseismic creep being recorded.
In 2001 Carracedo et al.;[8] stated that they consider the 1949 crack to be a shallow and inactive surface expression. They do suggest that the crack should be monitored, but consider the possibility that the edifice is unstable as being almost non-existent.
Murty et al.; (2005)[14] claim that the morphology of the Atlantic Ocean prevents the generation and propagation of trans-oceanic tsunamis. However the Tohoku tsunami of 2011 propagated to Hawaii and the coast of California, a distance much greater than a trans-Atlantic crossing.
In 2006 professor Jan Nieuwenhuis of Delft University of Technology simulated several volcanic eruptions and calculated it would take another 10,000 years for the flanks to become sufficiently high and unstable to cause a massive collapse.,[15]
A 2008 paper looked into this very worst-case scenario, the most massive slide that could happen (though unlikely and probably impossible right now with the present day geology). They find wave heights in the range 10 to 188 meters in the Canary Isles themselves. But the waves interfere and dissipate as they head out into the Atlantic. They predict 40 meters height for some nearby island systems. For continents, the worst effects are in Northern Brazil (13.6 m), French Guyana (12.7 m), mid-US (9.6 m), Western Sahara (largest prediction at 37 meters) and Mauritania (9.7 m). This is not large enough to count as a megatsunami, with the highest prediction for Western Sahara comparable to the Japanese tsunami, so it would only be a megatsunami locally in the mid Atlantic.[16]
An underwater eruption that began in September 2011 south of the island of El Hierro gave rise to more speculation about the possibility of a megatsunami.[17][18] As each island in the archipelago is an independent edifice often several tens of kilometres away from the adjacent island it is geologically impossible that volcanic activity on one island will influence the other islands. El Hierro lies about 100 km south of La Palma, over 100 km south-west of Tenerife. La Gomera – extinct since about 4 million year BP, Gran Canaria and Fuerteventura no eruptive history since about 10000 years BY, Lanzarote last erupted in the 19th century.
