Evacuation of smallest Canary Island begins after earthquake 'swarm' sparks fears of volcanic erupti

[dipsydoodle]

Source: Daily Mail

A holiday island popular with Britons is preparing for a mass evacuation because of a possible volcanic eruption.

Experts have recorded 150 tremors on El Hierro, the smallest of the Canary Islands, since yesterday - raising fears of an imminent eruption.

Last night 53 people were ordered out of their homes over fears of landslides and the army has been called in to prepare for a possible evacuation.

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Volcano expert Juan Carlos Carrecedo said: 'There is a ball of magma rising to the surface producing a series of ruptures which generate seismic activity.

Read more: http://www.dailymail.co.uk/news/article-2042873/Earthquake-swarm-Canary-Island-El-Hierro-sparks-fears-volcanic-eruption.html#ixzz1ZHoU28Z6


Read more: http://www.dailymail.co.uk/news/article-2042873/Earthquake-swarm-Canary-Island-El-Hierro-sparks-fears-volcanic-eruption.html

[Renew Deal]

1. Mega Tsunami Canary Islands to Eastern US

http://www.youtube.com/watch?v=3jlaiJRwU6Q

[dipsydoodle]

2. Its predicted

that if the slope of that one, Cumbre Vieja in La Palma, Canary Islands, fell into the Atlantic the tsunami would wipe out the entire US seaboard between Boston and Miami 50 miles inland c. 9 hours later.

some details here too : http://geology.com/noaa/atlantic-ocean-tsunami/

[Warpy]

5. Let's hope that's overstated

and would just mess everything up right along the seaboard. I have too many friends who live there and who would never be able to evacuate in time.

[alfredo]

6. Others are saying that worst case scenario is far fetched.

[izquierdista]

9. I have to call bullshit on that math

Let's take 1500 miles for the distance from Boston to Miami. Times 50 miles inland is 75000 square miles. Now what about height? The tsunami would have to be about 200 feet high to inundate a place like Statesboro, GA, which is 50 miles inland. So that is a thickness of about 1/25 of a mile, so we are talking a volume of water of say 3000 cubic miles.

No way is there 3000 cubic miles of stuff on La Palma to plop into the ocean to cause that kind of water displacement. Now what I calculated above is just for the effect in the U.S., and this purported tsunami is also going to be radiating north to Greenland and west to the Caribbean, so a lot MORE than 3000 cubic miles of displacement is required to cause this damage scenario.

Before people go swallowing this horror story, they should do the math -- it doesn't calculate out.

[blackspade]

10. The volume of the slide is only one factor of the tsunami.

Another is the transfer of energy caused by the displacement of the surrounding water into low frequency waves.
These waves pile up on the Continental shelf, magnifying the size and power of the tsunami.

[izquierdista]

11. Your post makes no sense

You want to try turning what you wrote into real physics?

[blackspade]

14. Perhaps this will help.

http://www.youtube.com/watch?v=_RMprH-4QC4

Basically the displacement of water is not the only factor. Air also displaces water and the combined energy is transfered through the water column to the sea floor. In the case of the Canary Islands, the water is very deep amplifying the power of the slide.

[izquierdista]

17. Still wrong

Wrong model, wrong set of assumptions, different initial conditions. See 'Estimation of Tsunami Initial Displacement of Water Surface Using Inversion Method with a Priori Information' by Nobuaki Koike at http://www.intechopen.com/articles/show/title/estimation-of-tsunami-initial-displacement-of-water-surface-using-inversion-method-with-a-priori-inf

[blackspade]

22. You asked, so I provided.

Perhaps you should read the your link more closely.
It does not, in fact, discuss sciorrucks, but seismicly created tsunamis.
So the model proposed in the link is not applicable to a tsunami caused by a landslide.

The link I provided discusses sciorruck tsunamis specifically, and is indeed the correct model, with the proper set of assumptions and initial conditions.

[izquierdista]

23. How?

Your link has the wave in a confined space, which would be all right for modeling Lituya Bay, but those are not good assumptions or initial conditions for a transoceanic wave. A landslide on an island across the ocean, just like a seismically generated displacement far enough away, is a point source Green's function.

[Bosonic]

25. Link to paper addressing potential 'La Palma Tsunami'

http://www.es.ucsc.edu/~ward/papers/La_Palma_grl.pdf

Abstract.
Geological evidence suggests that during a future
eruption, Cumbre Vieja Volcano on the Island of La Palma
may experience a catastrophic failure of its west flank, drop-
ping 150 to 500 km3 of rock into the sea. Using a geologically
reasonable estimate of landslide motion, we model tsunami
waves produced by such a collapse. Waves generated by the
run-out of a 500 km3 (150 km3) slide block at 100 m/s could
transit the entire Atlantic Basin and arrive on the coasts of the
Americas with 10-25 m (3-8 m) height.

[izquierdista]

27. All right!

Somebody who found some real facts! What I see here is that for a 500 km3 displacement, they calculate a wave of 10-25 m, which is certainly not going to inundate the East Coast from Boston to Miami for 50 miles inland. Which, I believe, is what I called Bullshit! on in the first place.

[blackspade]

28. Ah! Finally we have some happiness.

This might have been an enjoyable conversation if you weren't so arrogant.

[izquierdista]

29. I get that way when I'm right.

I don't suffer fools gladly. Especially the scientifically illiterate and innumerate.

[blackspade]

30. Your humility is overwhelming.

Coming from someone who had to have someone else bail them out in the conversation.

For your edification; three differing points of view on the subject:

The massive mega-tsunami: http://wet.kuleuven.be/wetenschapinbreedbeeld/lesmateriaal_geologie/wardday-lapalmatsunami.pdf

The counter study (which you have embraced): http://www.drgeorgepc.com/TsunamiMegaEvaluation.html

And somewhere in the middle: http://www.geo.arizona.edu/~andyf/LaPalma/

All good reading.
Too bad your arrogance got in the way of a potentially good conversation.
A helpful tip for the future: If you ask a question about a subject that someone provides an answer for, don't shit on it because you don't like it, or learn to use the google.
You could have easily looked it up yourself and attempted to educate, but I guess that would have gotten in the way of your smug self-satisfaction of being an internet curmudgeon.

[Thor_MN]

15. How about taking your own advice?

Do you really think it would work by completely submerging the entire affected area to your choice of depth (200 feet) for the entire duration of the event? That's what your proposed volume implies.

Here's a hint. It's a wave.

[Name removed]

18. Deleted message

Message removed by moderator. Click here to review the message board rules.

[Thor_MN]

24. If you cant\'t picture a wave rolling over a surface as not the same volume

as the entire surface flooded to the same height as the wave, you have absolutely no business trying to lecture people on geometry much less physics.

Either educate yourself or, again, take your own advice as STFU yourself. So far you have only demonstrated your ignorance.

[izquierdista]

26. Math, lets have some math.

Are you objecting to my step function model of the wave as it arrives at the East Coast? What other waveform would you use other than the integral of a delta function? If you want to use some other wave profile, can you integrate the waveform to get the volume of water required for such a flood event? Once you do, can you then say what size point source would be required on the other side of the ocean to cause such a wave?

Oh, and if you are going to model it with a two-dimensional Bernoulli equation, how much dispersion will there be?

[blank space]

12. Not how tsunamis work

Its more about frequencies that volume displacement.

Either way - a significantly smaller volume was displaced which wiped out massive areas on the west coast less than 200 years ago.

[izquierdista]

13. See post #11

[Blue State Bandit]

3. Wrong island.

La Palma Island is about 50 miles to the north.

[dipsydoodle]

4. Yes I know that

but its the same chain.

[bigworld]

7. sleep well, fellow east coasters :)

[Renew Deal]

19. lol

:hide:

[AtheistCrusader]

8. I think La Palma is the only known one with the dangerous slide/fault issue.

But a major eruption or quake could certainly produce a tsunami from there, to here. Even 'conventionally'.

[Ichingcarpenter]

16. El Hierro’s Volcanic/Seismic Past

El Hierro is situated in the most southwestern extreme of the Canaries. The island was formed after three successive eruptions, and consequent accumulations, the island emerged from the ocean as an imposing triangular pyramid crowned by a volcano more than 2,000 metres high.

The volcanic activity, principally at the convergence of the three ridges, resulted in the continual expansion of the island. A mere 50,000 years ago, as a result of seismic tremors which produced massive landslides, a giant piece of the island cracked off, crashed down into the ocean and scattered along the seabed. This landslide of more than 300km3 gave rise to the impressive amphitheatre of the El Golfo valley and at the same time caused a tsunami that most likely rose over 100 metres high and probably reached as far as the American coast.

According to the Global Volcanism Program, the massive Hierro shield volcano is truncated by a large NW-facing escarpment, seen here from the east, which formed as a result of gravitational collapse of the volcano. The steep-sided 1500-m-high scarp towers above a low lava platform bordering 12-km-wide El Golfo Bay, which is barely visible at the extreme left. Holocene cones and flows are found both on the outer flanks and in the El Golfo depression. The last eruption, during the 18th century, produced a lava flow from a cinder cone on the NW side of El Golfo.




In a BBC Horizon programme broadcast on October 12, 2000, two geologists (Day and McGuire) 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 high in the region of the islands. The wave would radiate out across the Atlantic and inundate the eastern seaboard of North America including the American, the Caribbean and northern coasts of South America some six to eight hours later. They estimate that the tsunami will have waves possibly 160 ft (49 m) or more high causing massive devastation along the coastlines. Modelling suggests that the tsunami could inundate up to 25 km (16 mi) inland – depending upon topography.






Lots of good seismic maps and data at the link.



http://www.irishweatheronline.com/news/earth-science/geology/canary-islands-government-raises-el-hierro-volcanic-alert-level/39623.html

[Bigmack]

20. Very informative post

Thanks.....and I hope that all this remains....."academic." Ms Bigmack

[Bigmack]

21. Very informative post

Thanks.....and I hope that all this remains....."academic." Ms Bigmack

[itcfish]

31. Lovely Island

I hope it does not happen. It's a lovely island and the people are warm and friendly. Stay safe Canarios!