El Hierro

[SurfJames]

A magnitude 5 earthquake would be more serious, fifi. It would be large enough to open
rifts in the ground. Magma could find a route to the surface.

Also, depending where it was centred, you could expect damage to buildings.

Is 5 powerful enough to trigger a tsunami?

[SurfJames]

Update 18/11 – 20:31 UTC
 The number of earthquakes has increased to 37 !, the highest number since November 11

Update 18/11 – 19:56 UTC
 - Following the locally well informed El Hierro Digital we might see a far better image from
the Las Restinga Telefonica webcams than we have had so far. The current 2 webcams will soon be
replaced by High Definition webcams. Reader Ian Carson reported earlier today that the new
 webcam was being installed on a far better and stable mast than the one before. Ian took a
couple of pictures which he shares with you.
 - The Cabildo and Telefonica will also install 2 new webcams (probably the onces they are taking away at La Restinga) in the El Golfo area.  Spoiled Childs as we are,
we will start asking from now on  for an infrared webcam at the Las Calmas sea.
 Gracias to the Cabildo President (Mr. Alpidio Armas) and
Telefonica on behalf of the earthquake-report.com readers.

[fifi]

Some of the older houses already have cracks in the walls. One resident recommended using a product which the Pharmacy  sells as a sealant. It is useful because it is not flexible (it seals like glass and will shatter showing the effect the tremor is having on their houses) I think it was PEVLOCA who said that houses in GOOD condition should be ok if an earthquake of that magnitude happened. I dont know what magnitude it would take to cause a Tsunami.

[jand]

There was a tweet from someone in Brazil on the new webcam site who said that it has been discussed that IF there is a Tsunami it could also reach South America.

Its amazing to see how many countries from all over the world are keeping a close eye on whats happening in El Hierro.

[jand]

http://www.01.ign.es/ign/head/volcaSenalesAnterioresDia.do?nombreFichero=EOSO_2011-11-18&estacion=EOSO&Anio=2011&Mes=11&Dia=18

The graph for Gran Canary has even had one of the long spikes.

Is it still being said that these are man made.

[SurfJames]

When they say 'man made' do they mean that they are firing explosives which get detected,
or has someone nudged the seismometer, causing the pen to skip across the paper !!  []

[pennylane]

cant admin delete the post that is making the page too wide ?
I love this thread but its a pain scrolling sideways every line to read it.
Or can everyone hit the return key sooner on each line they post pls

PL

[pennylane]

"Canarian Volcanologist Carlos Carracedo said that their crisis management is an International laughing stock.

Avcan are predicting a large earthquake magnitude 5 within 22/24 hours."


Disgraceful the residents should know this and giv them time to prepare...

Can't stand cover up's.[V]

[SurfJames]

quote:Originally posted by pennylane

cant admin delete the post that is making the page too wide ?
I love this thread but its a pain scrolling sideways every line to read it.
Or can everyone hit the return key sooner on each line they post pls

PL

I think we need to ask Admin to start a new page !

Glad to hear that you also love this thread.
The number of hits have been amazing. [8D]

[pennylane]

surfjames

this a good site too hun x
http://www.exploguide.com/site/teide-peak-hike-tenerife-island-canary

[pennylane]

surfjames Ive been following FiFi and Jand for weeks
now before we went on hol to Corrie..
I cant take all the stats and graphs in really
but it#s all so interesting and its drving me mad that
the Gov dont keep the residents informed
that's why these forums are so important so enthusiasts
can relay info to interested parties

PL x

[pennylane]

ha ha the 'forum owners' must be over the moon with
their increase in hits and of course the spin offs lool

plx

[SurfJames]

quote:Originally posted by pennylane

surfjames Ive been following FiFi and Jand for weeks
now before we went on hol to Corrie..
I cant take all the stats and graphs in really
but it#s all so interesting and its drving me mad that
the Gov dont keep the residents informed
that's why these forums are so important so enthusiasts
can relay info to interested parties

PL x

I couldn't agree with you more penny. Governments are custodians of a country for the benefit of the citizens.
But democracy has been manipulated by the super-rich and they see power
as a road to money and wealth. Countries get degraded as they get fat. And they work in a vaccuum and are secretive.
We need to wrestle back the power and accept that everyone needs a
fair share of a countries wealth.
Too many European countries are becoming run by unelected bankers.

Have a nice weekend. xx

[pennylane]

I check in everyday and put the web cams on
when I have my lunch then leave them on and
pop in now and then for an up date
and no for the cynics I'm not sad, got a busy
hectic life but this thread is so informative
and its educational.  If there's no Danger to
Fuerte then the regs shouldnt worry that this
thread will put tourists off.....everyone I know
will still be visiting Fuerte next year.
I am concerned for the residents of El Hierro though
and their lack of truthfull info..they deserve better.
I'm just hoping that some of them can get on line somehow to get
the info they need to prepare for anything.

[SurfJames]

Thanks for that link pennylane.

I plan to go hiking all over that volvcano next year! xx


Edited my rubbish spelling![:I]

[duncolm]

quote:Originally posted by SurfJames

A magnitude 5 earthquake would be more serious, fifi. It would be large enough to open rifts in the ground. Magma could find a route to the surface.

Also, depending where it was centred, you could expect damage to buildings.

Is 5 powerful enough to trigger a tsunami?

As I understand it from my reading:-
Triggering a tsunami doesn't depend on the magnitude of an earthquake, it depends on the seabed being forced upwards by the earthquake. The earthquakes in the Canaries are generally the result of movements of magma below the seabed or surface causing a shake, not the movement of the seabed itself. That would usually happen where one tectonic plate which is being forced under another (a subduction zone) and a jam gets released.

The nearest feature anything like a subduction zone is the Gorringe Bank, a ridge off the coast of Portugal. In 1755  a magnitude 8.6 earthquake at Gorringe Bank did famously trigger a tsunami, but that was massively more powerful than magnitude 5. Most of the subduction activity along that tectonic boundary (the pushing of the African Plate against the Eurasian Plate) is in the Med, not the Atlantic. The other tectonic boundary 'nearby' is the Mid-Atlantic Ridge. That is not a subduction zone, quite the opposite, it's a constructive boundary where material is coming up from below rather than being forced down. That is much less likely to generate a powerful earthquake.

The result is that the immediate chance of a major tsunami in the Eastern Atlantic is not nil, but very very unlikely.
(The most likely cause of a tsunami would be a landslide into the sea. The island of La Palma has been identified as a possible source of such an event and Tenerife has had a huge landslide in the distant past but I haven't heard of El Hierro being assessed as a major landslide risk.)

[SurfJames]

Cheers for this duncolm and welcome to the forum.

So it would seem that a Tsunami from the quakes is not likely, but a landslide could be a problem.

It will be interetsing to see what if the 5 happens over the next 24 hours as predicted.

[pennylane]

not sure if this has been posted before
http://thetruthbehindthescenes.wordpress.com/2011/11/11/volcano-earthquake-el-hierro-watch-nov-12-15-2011/

[pennylane]

This was funny on the mail online
sorry if youve seen it before

"It's not known at this point whether Ryanair, famed for flying to out-of-town airports, plans on opening up a route to the new-born island.

Homes have been evacuated and roads closed on the southern-most Canary Island following a government-issued warning about a possible volcanic eruption while shipping has been banned in the area.

The southern tip of El Hierro was shaken by a 4.3-magnitude quake late on Saturday as the underwater volcano just off the coast started spewing. The island, which has 500 volcanic cones, has


Read more: http://www.dailymail.co.uk/sciencetech/article-2059576/El-Hierro-Volcano-eruption-New-Canary-Island-emerges-underwater-volcano-rises.html#ixzz1e6XhDOrS

[pennylane]

Possible names for a new Canary Island have already been suggested
on the internet, such as Atlantis or Discovery

[pennylane]

sorry to be boring but am up all night with an 'after infection'
from a mossie bite on calf muscle..Doc said hospital but I cant with
fam committmentsso am drugged up and off on a tangent.....
yes I googled the info but I want to send this to the El Hierro Gov.

As the BIMBACHES people were the pre hispanic inhabitants
of El Hierro, before they were sold off as slaves by
Bethencourt when he took over the Island,
wouldn't it be a fitting tribute to the original inhabitants
to name the new Island after them " Bimbaches"

If our generation is really sorry about slavery this would
be a chance of showing it.

PL

just a thought but I will send it to their Gov.
or whoever has the job of naming a new island.....

[pennylane]

Fi , Jand and James and anyone else interested
this is a good read
too long to post on here but see it if you have 10mins
to read it x

http://rsta.royalsocietypublishing.org/content/364/1845/2009.full

[fifi]

quote:Originally posted by duncolm

quote:Originally posted by SurfJames

A magnitude 5 earthquake would be more serious, fifi. It would be large enough to open rifts in the ground. Magma could find a route to the surface.

Also, depending where it was centred, you could expect damage to buildings.

Is 5 powerful enough to trigger a tsunami?

As I understand it from my reading:-
Triggering a tsunami doesn't depend on the magnitude of an earthquake, it depends on the seabed being forced upwards by the earthquake. The earthquakes in the Canaries are generally the result of movements of magma below the seabed or surface causing a shake, not the movement of the seabed itself. That would usually happen where one tectonic plate which is being forced under another (a subduction zone) and a jam gets released.

The nearest feature anything like a subduction zone is the Gorringe Bank, a ridge off the coast of Portugal. In 1755  a magnitude 8.6 earthquake at Gorringe Bank did famously trigger a tsunami, but that was massively more powerful than magnitude 5. Most of the subduction activity along that tectonic boundary (the pushing of the African Plate against the Eurasian Plate) is in the Med, not the Atlantic. The other tectonic boundary 'nearby' is the Mid-Atlantic Ridge. That is not a subduction zone, quite the opposite, it's a constructive boundary where material is coming up from below rather than being forced down. That is much less likely to generate a powerful earthquake.

The result is that the immediate chance of a major tsunami in the Eastern Atlantic is not nil, but very very unlikely.
(The most likely cause of a tsunami would be a landslide into the sea. The island of La Palma has been identified as a possible source of such an event and Tenerife has had a huge landslide in the distant past but I haven't heard of El Hierro being assessed as a major landslide risk.)

Hi Duncolm, delighted you have come back to join us.[] El Hierro has had some very serious landslides in the past which have caused Tsunamis. http://www.earth.ox.ac.uk/~tony/watts/downloads/Gee_etal_ElHierro_2001.pdf

[fifi]

quote:Originally posted by pennylane

surfjames Ive been following FiFi and Jand for weeks
now before we went on hol to Corrie..
I cant take all the stats and graphs in really
but it#s all so interesting and its drving me mad that
the Gov dont keep the residents informed
that's why these forums are so important so enthusiasts
can relay info to interested parties

PL x

 Zapatero promised the Citizens of El Hierro every resourse they needed to cope with the crisis. He let them down.

 The El Hierro case is fascinating, better than any "soap" on the tv. The information from pretty much every source was wrong, and it is  causing frustration for everyone. The Canarian Government have been exposed as liars at an embarassing time, just before elections. The Islanders wanted to  barr the Politicians from the Island because they felt so let down by them. Because of my previous dealings with the Canarian Government with the Ryanair situation, and knowing from that the way that they can turn a situation to their advantage in the press, I have found researching this really interesting. There were no surprises for me.

What they did not expect is the strong reaction from the residents, who are intelligent people that  know quite a lot about volcanology. They knew when stations were not operating properly and when information was incorrect or missing.  The general feeling from reading all their messages seems to be ..we are small in numbers, if we were in the mainland of Spain would we have had to wait three months for a ship, would we have been treated better?

 Because of the number of hits on the webcam now El Hierro have decided to use the Volcano  to their advantage and capitalise on it, but the damage is done and they have lost the trust of the people.

...................

Thanks for the link Glen. I will read it in the morning.

[jand]

http://www.youtube.com/watch?v=96OvxIaE7gU

 Interesting Video From European Space Agency!!!!

[jand]

http://www.01.ign.es/ign/layoutIn/volcaSenalesAyerHoy.do#

Looking at the all the islands charts from yesterday everyone including Fuerteventura (except Lanzarote ) had movements and still on La Palama the graph is crazy,

These movements were not all the same on each island.

I have just thought surely this cant be military excercises on La Palma as why would they be doing soemthing (I presume dropping charges or explosives) on an island that could be part of a volcanic chain with magma moving underneath is this just not crazy!!!

[jand]

jonfr.com/volcano

My way is just to explain what I mean : magma chamber to the North (El Golfo) and eruption to the the South (La Restinga) ...
 I don't know why, but I think about "subsidence" (the weight of El Hierro island) ...
 After it means about magma take the easyeast way !

So, If you consider the earthquake before eruption, during and after, it don't think stupid.

I'd like to show 4D animation ! (3D+time)
 I have IGN localisation of earthquake, but nothing to do with that ...

I'm an old Fortran programmer, trying to do best, but I like Fortran, so I'm waiting for more until I'll do best ! (in a long time ...).

No time for me to do that, so the challenge is open !
 (but I think about)

Reply

Justice says:

 November 19, 2011 at 01:23

Fanfoe63... Hold that thought

Reply

Pablo Escobar says:

 November 19, 2011 at 01:32

Good job, could you redo it, but use the color scale as a graduation of seismic intensity from .5 to 4.0?

I haven't seen how the seismic intensity trend in relation to location and time.

I would conjecture that a pattern would emerge from looking at the data that way.

Reply

KarenZ says:

 November 19, 2011 at 01:50

Overview: http://oi42.tinypic.com/2wpt4yv.jpg
 Analysis: http://oi41.tinypic.com/fwqa0l.jpg

KarenZ says:

 November 19, 2011 at 01:52

And:

Latitude: http://oi41.tinypic.com/29gboue.jpg
 Longitude: http://oi44.tinypic.com/2571ws4.jpg

(reposted from last night)

KarenZ says:

 November 19, 2011 at 01:57

The rough time lines were a lot of activity in NW, W and SW Frontera (mainly SW Frontera) prior to a sequence of EQs at El Pinar before the emergence of Bob. The activity north of the ridge resumed very shortly after the emergence of Bob but deeper and larger EQs.

If you want a more detailed time line, watch the animation provided by avcan.org.

KarenZ says:

 November 19, 2011 at 01:43

But if there was subsidence we would not have seen elevation at REST, FRON and SABI.

Reply

M. Randolph Kruger says:

 November 19, 2011 at 03:18

Okay Karen... Now I challenge you to do the same thing that I asked for out of Lurk and I am sure he is figuring a way to do it. Boy is a genius.

Anyway. You go to zero at the top of the graphic. I think you need to establish the top at 6000 feet, then bring it down to zero so we can see if quakes are occurring IN the mountain. Hard as hell to tell and especially with dome quakes. You have to be parked nearly on top of the mountain or along the same strata to get good readings. E.g. Redoubt was monitored from a couple of miles away in the hut. Mostly because they didnt want to lose their gear. Later as it started to cha-cha, they flew up and set up gear on the backside and wow it got crazy after that for readings in the mountain.

This is because the quakes are up in the mountain and not below it. Thats where the magma will show up if its breaching it at the bottom somewhere.

We are kind of fortunate that the island is big enough to instrument it as it is.

Lurking says:

 November 19, 2011 at 05:12

You do realize that backing up to a higher elevation would require that quakes are recorded for those levels.

Usually, all depths are referenced to a baseline, in this case, I think that is sea level.

Quakes shallower than about 0.1 don't get a depth, nor do the ones with poor resolution.

For example:

2011/11/10 18:11:12.02 0.56 0.52 27.8627 -18.0447 2.8 2.0 4 0.0f 14 7 287 0.11 0.15 m i uk IGN 1111895

It had a lateral location error of 2.8km for the semi-major axis and 2.0 km for the semi-minor axis, oriented along 4° bearing for the major axis.

This is actually pretty good resolution, and fits with a lot of the other quakes that they have in the catalog.

But with a depth reading of "0.0f" it's a pretty good bet that it was either above their reference datum or that they just couldn't work out the location. Given the good values for the lateral position, "above the datum" might be a valid read.

We can make some assumptions, but they would be highly suspect, that blank depths may be "above the datum" and inside the mountains.

Dunno if I want to make that leap and post it in public. I would not want to freak people out for a whimsical evaluation on my part.

Lurking says:

 November 19, 2011 at 05:15

Also, since I'm on the subject. My batheymetric data became suspect when I plotted the La Restinga quakes near the Bob jacuzzi. According to the plot, they were above the seafloor. That's why I tossed that layer out a while back. It's good as an overall reference, but close-n-tight it was worthless.

[jand]

Glen

Thank you for your link its fascinating.

I have just copied part of it below.

The history of landslides in the Canary islands over the past one million years is now well understood (see Masson et al. (2002) and references within). The bulk of landslide activity is associated with the youngest and most volcanically active islands of Tenerife, La Palma and El Hierro (figure 6). On average, one landslide has occurred somewhere in the Canary islands every 100#8202;000 years, although this figure masks an irregular distribution through time (Masson et al. 2002). The youngest landslide occurred on the island of El Hierro some 15#8202;000 years ago. Most of the landslides are debris avalanches, with slumps only recognized on the youngest island, El Hierro, perhaps suggesting that this landslide style is a feature of early island development. A typical Canary island debris avalanche is marked by a near-vertical amphitheatre-shaped headwall on the island, an erosive chute on the upper part of the submarine island slope and a pile of avalanche debris at the foot of the steepest island slope, usually at 3000–4000#8202;m waterdepth (figure 7). This typical avalanche has a volume of 50–200#8202;km3, covers an area of a few thousand km2 and has a run-out of 50–100#8202;km. Glide planes at the base of the landslide are typically up to 10° on the upper slope, decreasing to less than 5° on the lower slope (Watts & Masson 1995; Gee et al. 2001; Watts & Masson 2001). Large accumulations of debris, such as seen north of Tenerife or west of La Palma, are clearly the cumulative result of several landslides rather than single larger events that have occurred in the past. Even some deposits thought to be the result of a 'single' landslide event (in geological time) show signs of more than one phase of emplacement (Watts & Masson 2001). It is notable that Canary island debris avalanches are an order of magnitude smaller than those on Hawaii, possibly reflecting the larger size and higher magma production rates of the Hawaiian islands or the more rapid development of instability on the relatively steeper Canary island slopes.

Figure 6
Location and ages (in brackets) of large landslides on the western Canary islands. The Cumbre Vieja Ridge is recognized as the likely site of a future landslide.

Figure 7
Two views of the El Golfo debris avalanche on the island of El Hierro, western Canary islands (for location see figure 6). (a) Shows a plan view shaded relief image, illuminated from the northeast. The limits of the area affected by the landslide are outlined in red. Note that avalanche blocks are scattered randomly on the landslide, although there is a notable concentration of blocks in the centre of the deposit. (b) Shows an oblique shaded relief model viewed from the northwest. The avalanche headwall on the island is about 1000#8202;m high.


Canary island landslides identified as debris avalanches according to the definition of Moore et al. (1989) show a variety of structures that suggest elements of both debris avalanche and debris flow emplacement mechanisms (figure 8; Masson et al. 2002). In addition, these landslides can also initiate turbidity currents that are capable of flowing considerable distances downslope. Sediment cores recovered from the deep Agadir Basin, about 300#8202;km to the north of the islands, contain turbidite deposits which, based upon their mineralogy, geochemistry and age, are interpreted to be linked to Canary island landslides (Wynn et al. 2002; Wynn & Masson 2003). Specifically, a turbidite deposited at #8764;15#8202;kyr is linked to the El Golfo landslide on El Hierro, while an older turbidite dated at ca 170#8202;kyr is linked to the Icod landslide on Tenerife. Most turbidite deposits in the Agadir Basin are actually derived from the Moroccan continental margin to the east (Wynn et al. 2002), and show the typical smooth upward-fining grain-size profile that is typical of graded turbidite deposits (figure 9). However, the two turbidites derived from Canary islands landslides show a stepped grain-size profile that appears to represent deposition from a series of 'mini-turbidites' (figure 9). This pattern is interpreted to be the result of a multi-stage source landslide, as other potential causes, e.g. flow reflection, multiple pathways or pulses, can be ruled out (Wynn & Masson 2003). This hypothesis is also supported by the fact that similar turbidites linked to Hawaiian landslides show the same pattern of stacked mini-turbidites (Garcia 1996). Detailed sedimentological analysis of the Agadir Basin turbidites has revealed that their source landslides probably occurred in several retrogressive stages over a period of hours or days rather than weeks or months (Wynn & Masson 2003). Assessing the sedimentary record of deposits derived from these landslides is therefore critical when assessing their tsunamigenic potential, since it is clear that a series of smaller landslides spread over several hours will have a much smaller tsunami-building potential than a single large, instantaneous landslide (see §8).

The generation and propagation of tsunamis resulting from earthquakes have been studied for the last 50 years and are now relatively well understood (Bardet et al. 2003). In contrast, the importance of tsunamis generated by landslides has only become widely recognized during the last fifteen years or so, when it became apparent that a landslide source could explain the unusual run-up distributions and propagation characteristics of certain particularly deadly tsunami, such as the 1998 PNG event (Ward 2001; Bardet et al. 2003 and references therein; Okal & Synolakis 2004). However, the complexity and variability of submarine landslides means that we are still some way from a comprehensive understanding of the range of tsunamis that landslides are capable of producing. Modelling of landslide tsunamis has shown both that extreme wave heights of hundreds of metres might be possible (Ward & Day 2001; McMurty et al. 2004), but that models are sensitive to the geological input parameters and the hydrodynamic assumptions adopted in the model (Ward 2001; Haugen et al. 2005; Lovholt et al. 2005), with the result that poorly constrained model predictions will have large uncertainty.

[jand]

http://www.01.ign.es/ign/resources/volcanologia/html/deformacion.html

There are many comments relating to the link above about about El Hierro and the deformacion of the island and they are discussing and asking if there is now a possibility that the island could eventually split?

One comment posted below,

All the deformation charts are up to date now. It would appear as though every other island is falling during these events, while Hierro is steadily rising on ONLY HALF THE ISLAND! We're talking about a split people, a break in the island itself!

Quote from IGN

Deformación
Las deformaciones siguen el mismo patrón de estabilidad que en días anteriores en las componentes horizontales. Se observa una clara deflación en la componente vertical de las estaciones situadas en el sur y este de la isla, en la zona de El Golfo en la que se observa una estabilización en la elevación al oeste y una ligera tendencia a la deflación al este."

Translated:

"Deformation
 The deformations follow the same pattern of stability in previous days in the horizontal components. There is significant deflation in the vertical component of the stations in the south and east of the island in the Gulf area in which there is an elevated plateau in the west and a slight tendency for deflation to the east." via google translate

[jand]

Comment from Spanish person on Avcan 1 hr ago

Es posible desde mi punto de vista que el tremor disminuya por el ensanchamiento de la fisura de emisión actual.Un atasco en el conducto provocaría un aumento de la sismicidad por detrás de la obstrucción. A nadie se le ha ocurrido pensar que este proceso tiene ciclos perfectamente definidos desde hace tres meses y que está en una etapa de reposo.? El próximo aumento de emisión tendrá lugar, sin ningún lugar a dudas por nuestra parte, del 28Noviembre al 10 Diciembre.

It is possible from my point of view that the tremor decreases by the widening of the fissure of current emissions.A jam in the duct would lead to an increase in seismicity behind the obstruction. Anyone has think that this process has perfectly defined cycles over the last three months and that it is in a resting stage thought.? The next emission increase will take place, without any doubt on our part, to the 28Noviembre to 10 December. (Translated