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Earthquake Swarm (11000+) El Hierro, Canary Islands

  • 23-07-2011 6:41pm
    #1
    Registered Users Posts: 11,134 maquiladora


    There is currently a very large earthquake swarm happening in the Canary Islands, at El Hierro.

    This pic shows the swarm at 368 but there is now over 400 and it's still going.

    http://twitpic.com/5um4vi

    I've only just stumbled on this in the Eruptions blog so I'm still trying to find some more links, live data etc.

    This could well be the prelude to a volcanic eruption on the island.

    As far as I know there is currently no indication that this activity could trigger a collapse/tsunami, but seemingly it has happened in the past :
    Islands of volcanic origin, such as the Canaries, have an especially large potential for triggering a tsunami. That the Canaries constitute a danger was shown 300 000 years ago when a part of the island El Hierro slid into the sea, triggering a mega-tsunami which carried rocks as high as a house for many hundreds of metres into the interior of the east coast of what is today the USA.
    http://www.tsunami-alarm-system.com/en/phenomenon-tsunami/occurrences-atlantic-ocean.html

    Information of the Geology of El Hierro here : http://www.elhierro.com/geologia-en.html


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Comments

  • Registered Users Posts: 5,068 ✭✭✭ Iancar29


    There is currently a very large earthquake swarm happening in the Canary Islands, at El Hierro.

    This pic shows the swarm at 368 but there is now over 400 and it's still going.

    http://twitpic.com/5um4vi

    I've only just stumbled on this in the Eruptions blog so I'm still trying to find some more links, live data etc.

    This could well be the prelude to a volcanic eruption on the island.

    As far as I know there is currently no indication that this activity could trigger a collapse/tsunami, but seemingly it has happened in the past :


    http://www.tsunami-alarm-system.com/en/phenomenon-tsunami/occurrences-atlantic-ocean.html


    How regular are such swarms for the Canarys?

    Looks serious!


  • Registered Users Posts: 11,134 maquiladora


    Iancar29 wrote: »
    How regular are such swarms for the Canarys?

    Looks serious!

    As far as I know its the biggest swarm for anywhere in the Canary Islands for 40 years. Last time there was anything like was before Teneguía erupted in 1971, but that was on La Palma, so I think this is the biggest swarm that has ever been recorded at El Hierro.

    No need to panic though, if there is an eruption it will probably be a small one, but it might look pretty! :)


  • Moderators, Technology & Internet Moderators Posts: 17,098 Mod ✭✭✭✭ cherryghost


    Why isn't USGS picking up on any of this? Too small to be considered?

    Well according to his twitter account the quakes are getting shallower and shallower


  • Moderators, Technology & Internet Moderators Posts: 17,098 Mod ✭✭✭✭ cherryghost




  • Registered Users Posts: 11,134 maquiladora


    Why isn't USGS picking up on any of this? Too small to be considered?

    Well according to his twitter account the quakes are getting shallower and shallower

    Yeah I don't think USGS show small earthquakes for areas outside the US (guessing). I think the biggest quakes in this swarm are around 2.3, not very big, its the sheer number of them thats interesting.


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  • Closed Accounts Posts: 5,070 ✭✭✭ ScouseMouse


    I'm sitting here in Tenerife and there is nothing about it.


  • Registered Users Posts: 5,775 ✭✭✭ up for anything


    GEOLOGY

    The island of El Hierro is situated in the most southwestern extreme of the Canaries at 27.7º north and 18.0º west, and is the smallest of the archipelago at 278.5 km2.

    El Hierro was designated by UNESCO as a Biosphere Reserve in the year 2000, with 60% of its territory protected to preserve its natural and cultural diversity.

    It's no wonder that the smallest Canary Island delights all who visit, not only for its great natural and ecological attractions, but also for the contribution of its inhabitants in the sustainable development and conservation of the natural and hereditary wealth of the area.
    The origins of the island date back some 100 million years when the ocean floor shifted with the movement of the earth's mantle. The crust consequently cracked into a three pointed star releasing flows of magma.

    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 initial crevices became channels for further lava flows which grew into three mountain ridges topped by numerous volcanic cones. While the magma cooled in these channels, it solidified into gigantic vertical basalt dykes, typical of the geological architecture of El Hierro.

    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.

    Although over 200 years have elapsed since the last eruption, El Hierro has the largest number of volcanoes in the Canaries with over 500 open sky cones, another 300 covered by the most recent outflows, and some 70 caves and volcanic galleries, notably the Don Justo cave whose collection of channels surpasses 6km in length.

    http://www.elhierro.com/geologia-en.html


  • Banned (with Prison Access) Posts: 25,234 ✭✭✭✭ Sponge Bob


    We are largely tsunami 'masked' by La Palma and Madeira to the north.


  • Registered Users Posts: 11,134 maquiladora


    I'm sitting here in Tenerife and there is nothing about it.

    This was a report from yesterday I found.

    http://www.islandconnections.eu/1000003/1000043/0/33677/daily-news-article.html

    There's nothing to be worried about really. It's just a very large swarm of small quakes and may indicate a new eruption may be on the way at some stage. I'd say the chances of anything more dramatic than that happening are very slim.


  • Registered Users Posts: 5,775 ✭✭✭ up for anything


    However, if you're on holiday in the Greek Island it might pay to keep an eye on this.

    http://ismosav.santorini.net/

    :pac::pac::pac:

    ETA: That was a joke comment. Bad joke. Sorry.


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  • Closed Accounts Posts: 423 ✭✭ je55ie


    However, if you're on holiday in the Greek Island it might pay to keep an eye on this.

    http://ismosav.santorini.net/

    :pac::pac::pac:

    Clicked on link, cant really follow... can you explain what you see? friend heading to crete on monday!!


  • Registered Users Posts: 5,068 ✭✭✭ Iancar29


    I knew i seen this on tv !....

    DONT WATCH IF U GET WORRIED EASILY!




  • Registered Users Posts: 83 ✭✭ morticia2


    Iancar29 wrote: »
    I knew i seen this on tv !....

    DONT WATCH IF U GET WORRIED EASILY!

    That one refers to Cumbre Vieja on La Palma, though, not El Hierro.

    There is also, I think, an academic dispute as to whether it would all collapse in one fell swoop (nasty wave), or in smaller sections (local, not transatlantic problems)

    http://en.wikipedia.org/wiki/Cumbre_Vieja


  • Registered Users Posts: 11,134 maquiladora


    Swarm is still ongoing.

    Here's the chart from the last hour, 2 small quakes visible there.

    http://www.01.ign.es/ign/head/volcaSenalesDiasAnterioresHora.do?nombreFichero=CHIE_2011-07-23_18-19&estacion=CHIE&Anio=2011&Mes=07&Dia=23&tipo=1&hora=18-19

    According to David Calvo, swarm total stands at 425 at the moment.


  • Closed Accounts Posts: 423 ✭✭ je55ie


    Anyone got info on Santorini??


  • Registered Users Posts: 5,775 ✭✭✭ up for anything


    jessie37 wrote: »
    Anyone got info on Santorini??

    Sorry, pet, I should have put a disclaimer at the end of the post declaring that I was taking the piss because I'm a bitter, jealous, twisted person who is not going anywhere nice this summer. There has been a little bit of activity there but nothing at all to worry about. Your friend can enjoy her holiday without having to give a second thought to anything happening other than that one in 10,000 event but you'll have that anywhere.


    ETA: That site won't let you in without a password. I don't have one either. I just saw a page with EQs listed for Santorini the day before yesterday so the person who posted the link obviously had a password. None of the Greek sites I've located have the names of places listed, just the co-ordinates.


  • Closed Accounts Posts: 423 ✭✭ je55ie


    Sorry, pet, I should have put a disclaimer at the end of the post declaring that I was taking the piss because I'm a bitter, jealous, twisted person who is not going anywhere nice this summer. There has been a little bit of activity there but nothing at all to worry about. Your friend can enjoy her holiday without having to give a second thought to anything happening other than that one in 10,000 event but you'll have that anywhere.


    ETA: That site won't let you in without a password. I don't have one either. I just saw a page with EQs listed for Santorini the day before yesterday so the person who posted the link obviously had a password. None of the Greek sites I've located have the names of places listed, just the co-ordinates.


    Phew!.... thanks for replying, just couldn't find any info on this anywhere...and your not bitter, I enjoy your updates on here so no worries, keep up the good work... :)


  • Registered Users Posts: 11,134 maquiladora




  • Registered Users Posts: 11,134 maquiladora


    Update for anyone that is interested.

    The swarm continued through the night and the total number of quakes is now close to 500.

    No signs of any imminet eruptions and right now the swarm has calmed down a lot.


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  • Registered Users Posts: 11,134 maquiladora


    Seems the swarm hasnt stopped, it just paused for a bit, here is the last hour.

    CHIE_2011-07-24_15-16.jpg


  • Registered Users Posts: 5,775 ✭✭✭ up for anything


    Just thinking... we should have a Kilkenny Beers or star/river watching session from the Rivercourt terrace. There seem to be enough of us around and about KK. There's the Tonynator, Maquildora (you are KK too aren't you), Min, Oscar Mike and I'm sure I've a seen a few others. We could pretend we were stuck at the top of snow covered, erupting volcano with a tornado bearing down on us. :D


  • Registered Users Posts: 11,134 maquiladora


    Biggest quake of the day so far within the last hour. Can you spot it? :P

    CHIE_2011-07-24_20-21.jpg


  • Registered Users Posts: 401 ✭✭ RoisinD


    Biggest quake of the day so far within the last hour. Can you spot it? tongue.gif

    Usually I cannot decipher those charts but even I can see that one:)

    Many thanks for keeping us updated, I am following this thread with great interest.


  • Registered Users Posts: 11,134 maquiladora


    This swarm at El Hierro has now clocked up over 500 earthquakes over the past few days and its still going.

    Total number of earthquakes for all of the Canary Islands last year was 88.


  • Closed Accounts Posts: 3,761 chucken1


    Sorry, pet, I should have put a disclaimer at the end of the post declaring that I was taking the piss because I'm a bitter, jealous, twisted person who is not going anywhere nice this summer. There has been a little bit of activity there but nothing at all to worry about. Your friend can enjoy her holiday without having to give a second thought to anything happening other than that one in 10,000 event but you'll have that anywhere.


    ETA: That site won't let you in without a password. I don't have one either. I just saw a page with EQs listed for Santorini the day before yesterday so the person who posted the link obviously had a password. None of the Greek sites I've located have the names of places listed, just the co-ordinates.

    So the red star isnt an eruption?? Ive friends living there :(


  • Registered Users Posts: 5,775 ✭✭✭ up for anything


    chucken1 wrote: »
    So the red star isnt an eruption?? Ive friends living there :(

    According to the legend/key it looks like an 1.1 earthquake. Nothing to fret about. :)

    If there's a mod about please could you delete my unfortunate post before the Daily Mail get here and quote my expert opinion. :D


  • Registered Users Posts: 11,134 maquiladora


    According to David Calvo the the total number of earthquakes in this swaem so far is now over 570.

    The swarm is picking up again in the last 30 mins or so.

    CHIE_2011-07-25_08-09.jpg


  • Registered Users Posts: 11,134 maquiladora


    Where can we check out the magnitude and depth of the tremors?


    http://www.ign.es/ign/layoutIn/sismoListadoTerremotos.do?zona=1&cantidad_dias=10

    However it's not very useful, when I have looked at it sometimes its up to date, sometimes in hours out of date, sometimes it reverts back to the previous day and it doesn't seem to show a full list of all the quakes.

    I guess they are struggling with trying to record and review all these quakes. There's been more earthquakes recorded around El Hierro in the past week than there has been in all the Canary Islands over the past 5 years combined.


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  • Registered Users Posts: 3,087 Duiske


    Maq, thought you might find these couple of blog posts by Andy Scollick interesting, if you have not seen them already. http://bigthink.com/ideas/39267

    And this, a link he provided in one of the posts. Tsunami warning system for Ireland


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