Category Archives: Bob

Keeping a close eye on El Hierro and NtV Riddle

The situation in El Hierro is interesting but it is unlikely an eruption is already taking place because there are no reports of stains so far. We here on Volcanocafe have a soft spot for this island because the action there in autumn/winter 2011 was one big reason why this blog came into existence at all. So here is the newest information I could assemble today.

CTAB_2013-03-22

CTAB_2013-03-22

Map of the stations at El Hierro

Map of the stations at El Hierro

Sites were you can get information:

Earthqake Report has a nice summary of the 2011 eruption. Reading this might bring back some memories.

Early february 2013 Involcano reported that there had been more vents to the west of the island. M Betzwieser reported.

Involcan admitted 5 more vents.

Involcan admitted 5 more vents.

I personally do not think an eruption is imminent because it took month of earthquakes till “Bob” became visible and watchable on the cams last year. But something is definitely going on and the information is by far not as good as in other countries like Iceland. Last year, while we all watched the spot of the shore of La Restina there was also an eruption of the west point of the island and if you watch the pattern of earthquakes it seems likely to me that something could go into action there again. But this is only a personal speculation.

Update:

Islander noticed the graphs have been downscaled! ( Just like it happened last year)

Renato Rio noted:
“Here is an image of possible emissions of gas Radonium from present activity in El Hierro.
I suspect we have a vent, and this time I really mean it.”
https://fbcdn-sphotos-a-a.akamaihd.net/hphotos-ak-prn1/c128.0.403.403/p403x403/31445_568621886504541_324729827_n.jpg

Manfred Betzwieser reported that the latest earthquakes happened in a depth of 13km and that the ship “Roman Margaleff” is on its way to the western tip of the island. ( Site is in german.)

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A page had been created here last year called Wonder what Bob is up to. It contains a huge ammount of links and papers. Maybe some links are out of date (the cam links are for sure) but i do not have the time to check them all again. So maybe you people here could help me check and update them. Please leave a comment directly at “Wonder what Bob is up to” and i ll try to work in the “news” in a.s.a.p.

Here is what is stored there so far:
Wonder what Bob is up to?

Some links to monitor our Bob & his mysterious-though-as-yet-hidden friends at El Hierro:

Info about Canary islands:

  1. Detailed map of Canary Islands - use Busquedas to find a particular place or check the 3D lidar model
  2. IGN variation of Google maps – Iberpix
  3. Geological map of El Hierro
  4. Volcanic history of Canary islands
  5. El Hierro – videos from the air
  6. Aerial photos of Canary islands
  7. Beautiful photos of El Hierro

Webcams:

Tanganasoga related info:

  1. Location on map and Google Earth picture (by Sissel)
  2. Longpre et al. 2009, Ankaramitic Lavas and Clinopyroxene Megacrysts From the Tanganasoga Volcano, El Hierro Island (Canary Archipelago), AGU 2009

Chemical composition

Floating stones off El Hierro, Canary Islands: xenoliths of pre-island sedimentary origin in the early products of the October 2011 eruption. Published on solid earth net.

An eclectic collection of scientific papers related to El Hierro, as suggested by readers . Please, suggest some more:

Spica

Name those Volcanoes Riddle

Note – this weeks riddle is a little different …. In order to identify each volcano you have to establish a link (some are more tenuous than others) between the volcano and various classifications, dates, places, events, people etc …. each clue has three genuine links and one ‘red herring’ included!

1 point for each correct volcano and 1 point for each ‘red herring’ (which must be identified with an explanation) guesses wont count ….. good luck!

No 1 - Lord Byron; November 5th 2013; Lethal mud slides; Pacific Ring of Fire;

No 2 - Stratovolcano; Canada; Formula 1; Angels;

No 3 - Stromatolites; 40,000; Rain forest; UNESCO; SOLVED

No 4 – UK; Dormant; Summer Rain; Vintage Car Museum;

Kilgharrah
Update:
IGN Graph showing latest ‘action’ 23.3.2013Imagenes sismicas para ese dia

A brief update on El Hierro

This image from the tourist bureau gives quite a good perspective on the island of El Hierro and La Restinga. One just need to lift the eyes to see the volcanic edifices looming over the villcage.

As the smoke starts to clear at El Hierro we get a much more detailed picture of what is happening. As data has poured in we can now deduce a few things.

First of all GPS figures today confirmed that this is indeed a fourth bolus of magma coming up from the depth.  The first one in July 2011 started the entire hubbub and in the end caused the sub-aquatic eruption south of La Restinga. A second bolus in January that followed the same path revigorated the ongoing eruption briefly, but was too small to keep up the pressure in the volcanic system and the eruption dwindled to a halt. The third bolus is so far the most interesting, during a few days more magma arrived than during the first one that caused the eruption. The magma arrived at the same place as for the first two (around the Tanganasoga volcano), but then it took an entirely new path and created quite a few earthquakes as it moved towards the western point of the Island. The fourth bolus also arrived at Tanganasoga, and immediately started to move south and slightly downwards.

Image by IGN. GPS data points for the uplift, figures are aproximatly 2 days old.

We still have only one set of data points for the GPS, but since it is visible on many of them it is still credible. What is a good test for if there is actual inflation or not is to check for motion in EW and NS directions. A false read normally does not show that.

The earthquake swarm is very vigorous with more then 100 earthquakes per day. The pattern is still continuing with a south and slightly down dipping motion. We will see if the hard tested village of La Restinga will have to suffer both the knowledge and the feeling of magma moving straight down under their feets.

Image by IGN.

We can also rule out any degassing or actual small eruption, what initially looked like harmonic tremor are most likely small earthquakes, there is no clear signal showing harmonic tremor to this date.

Image by IGN. No harmonic tremor showing on the charts now. So, no eruption, or no de-gassing.

There is no way to know if this bolus will cause an eruption or not. The lack of harmonic tremor says that it will at least not happen within the next 24 hours or so. But, for the residents on El Hierro the same advice is always valid, stay on top of the news.

CARL

Salud El Hierro!

The thermal hot spring bath of Balneario Pozo la Salud. Quite likely the new “to be at” spot for Jacuzzi watching.

The volcanic island of El Hierro is really turning into the Little Volcano that Could.

3 earthquakes seem to have changed the ballgame around once more.  First came two deep earthquakes at a new spot at 10.10 in the morning, both of them at the depth of 20 km. 26 minutes later followed a 2.6M at 10 kilometers depth.

Within minutes a sharp increase was noticed in the high frequency tremor. The tremor lacks low frequency components making this a dead giveaway that we are seeing a de-gassing event. What has happened is that a persistent earthquake swarm north of Balneario Pozo La Salud most likely finally cracked through and things started to move up beyond the de-gassing threshold.

Image by IGN. Please notice the lack of tremor at the lower frequencies.

After the 10.36 earthquake the shallower earthquakes pretty much disappeared and we had an onset of a new active deep earthquake swarm. In retrospect it is clear that we most likely caught the arrival of a new bolus of magma arriving from depth. If so it is the fourth time new magma arrives from the depth.

The deep earthquake swarm roughly follows the same pattern as for the previous 3 arrivals. Activity started at 20 kilometers depth at Tanganasoga, and then moved outwards and slowly dipped deeper. Every arrival has taken a slightly different direction; this one is moving into what can only be seen as pristine territory.

Image by IGN. Notice the 10km swarm north of Pozo la Salud, and the arrival of the new magma at 20km around Tanganasoga, this time moving roughly towards La Restinga area with a slow dip downwards. Remember that it never went this way during the Eruption of Bob south of La Restinga.

It is still too early to see anything on the GPS, but it should start to be visible tomorrow.

Question then is where is the de-gassing happening? My guess is that the guests of Balneario Pozo La Salud might have an interesting wake up call. If they are lucky they will have a brand new hot water Jacuzzi out in the ocean. For those who do not know, Pozo La Salud is a thermal spring bath in El Hierro.

CARL

Friday riddle is still unsolved:

I am the stony product of music that make Pavarotti mate a canis canis sheep mixture, I am spawned out of the apothecary.

What am I? And what is my origin? 3 points to be had, 2 for the name of “What am I”, and 1 for the origin. There is also a cunningly hidden bonus point out there…

VC Sunday Special

Last night the inhabitants of El Hierro were shaken by a series of earthquakes again, but all calmed down after an hour or so and the earthquakes were still rather deep.

IGN Station CTAB IGN Station CHIE

Our faithfull commenter DFMorvan frequently adds plots to his place: http://eruptionelhierro.blogspot.fr/2012/07/density-plots-video-from-june-24th-to.html
The last video he uploaded to Youtube shows the density of the quakes till yesterday afternoon so it does not include last nights show.

We are still waiting what El Hierro has stored for us. And while we are waiting, i will try to explain the menu on Volcanocafe a little. But before that, here are the winners of the friday riddles by AlanC!

Henri le Revenant got Chiastolite a variation of Andalusite and Talla and Carl? got Swedenborgite! ( We need to ask AlanC again because Carl claims he did not earn a point.)
Here are 2 images of those minerals:

Chiastolite Swedenborgite
http://www.minfind.com/mineral-45870.html http://www.mindat.org/

When Spica was made admin, i started resorting and renaming the menu  and tried to stick with terms which would suit a coffe shack or a bar in a pirates ship. As long as I find, people here do not really make a lot of use of the information provided by VC, i will now explain, what you can find where, without having to use Google.
We will continue on to collect usefull links, papers and webcams, so please leave a comment if you have something you think is important, best on the page or post where it should be added.

Home: Thats the place where all new posts show up and where you end up when you only go to volcanocafe.wordpress.com. This is the most frequented place.
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Welcome to Volcanocafe: was posted by Carl when the place first opened, you can find the idea behind all of this there, as well as some rules.
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Treasury: This was started by me to help sorting the different topics.

It is a drop down menu, as you see.

International treasures: gives a list of vocano observatories outside Europe. Things are being added as they come up. I am not trying to collect all avaiable links worldwide, just those were some  action is going on or is to be expected. Trying to have “all” would require checking tons of links ever so often and i just do not  have the time for this.

Archive sorted by date published: selfexplaining

Archive sorted by topic: selfexplaining. Again i am not trying to store “all” links, same argumentation as above. But this was designed to help finding older posts, for whatever reason.

Wonder what Bob is up to: Gives links, and papers to monitor or understand what is going on around El Hierro better.

Wonder what is going on in Iceland: Same as above, but this time with links and papers for Iceland.

Wonder whats going on in Santorini: Here you can find links and papers if Santorini should decide to be more active again.

Italian Job: Tons of Etna webcams and links to observatories and other pages regarding volcanic action in Italy. ( This page really needs more dedicated work by me )

In case some action starts to happen in some other place, and we on VC watch it closely, another menu point will be added here, so not to overwhelm the other archive pages.
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Gems: Another drop down menu, but with only 2 bars at the moment.

If you klick Gems directly, you end upon a page with beautiful images our readers took from webcams.

Gems without any relation to volcanoes: Here you could find how to change your avatar or how to make a video or a snapshot  from a webcam or how to add a smiley
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Library: Must-read books for volcanophiles can be found here.
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Crow`s nest: Has 2 bars in the drop down menu.

Volcano webcams: selfexplaining

Auroralinks: Is here because so many on VC love to watch auroras.
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OT Regulars table: OT ( Off Topic )  posts goin here. Originally i wanted them to appear only in here and not in home, but i could not figure out how to get this fixed.
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Burfell Dalek BBQ: Comments on the planning of a BBQ in front of a Heklacam went in there.This will be renamed or trashed soon.  We could make it a place where people could arrange meetings like said BBQ or volcano-tours? What do you think?

I am hoping you will contribute to development ofthe blog and leave comments with links. I am always up for constructive criticism so just let me know if you have ideas.

Spica

El Hierro – What did Elvis have to do with the Island?

Photograph by unknown. Orchilla Lighthouse, famous for being “The end of the World”.

During the night life got fairly interesting in El Hierro as the residents woke up from no less than two earthquakes above 4M. The larger of these two reached 4.4M.

Otherwise it seems like the magma continues to move in a general southwesterly direction. This has had as an effect that many of the GPS stations on the island is registering a downfall. It is at the moment uncertain where the magma is going.

The activity that we have seen during the last weak and a half is a sill intrusion, or a horizontal oblong shaped flat intrusion between different layers of rock. The intrusion has happened at great depth, around 20 kilometers deep. The activity started roughly under the old volcano of Tanganasoga, and then progressed towards the south east, passing the famous lighthouse of Las Orchillas on the way. The lighthouse is famous for being called “The End of the World”, a strangely fitting denominator when taking the current activity into account.

If we look closer at the 4.4M earthquake it had some rather intriguing features. It had a very weak transient in the beginning. The transient is the initial earthquake that is starting the rift of the fault plane, it was around 1.9M in this initial phase. After that a heavy magmatic component started as magma gushed in to fill the void left by the earthquake, and as the magma entered it further delaminated the layers in the rock, and more magma flooded in and so on and so forth. Let us just say that it was a lot of magma moving very rapidly.

Image by IGN. The earthquake starts at roughly 41 minutes, and it continued for 6 minutes before ending.

The angle was also rather interesting. The fault plane was tilted at 134 degrees, so the propagation of the earthquakes fault plane was going upwards at an angle. This gave the earthquake a fairly hard profile to plot, and both location and depth was changed due to this. Initial depth was set at 12 kilometers, as that was the end point of the faulting, but the beginning of the faulting was at 21 kilometers. And at an angle of 134 degrees this makes the start and finish line of the earthquake being somewhat different in location.

The earthquake was both Long Period, and a of the Broadband type. What I like to call a wet earthquake as oposing the dry earthquake that is associated with tectonic movement. It also look quite a bit like the sonic signature of water moving unexpectedly in a tube.

Worried in El Hierro?

The activity is right now inconclusive. The activity has started to show higher up, but the bulk of the earthquakes is still deep down. So it is fairly impossible to say where an eruption might occur. Some believe that it will happen in the western part of the island, or out at sea south to southwest of the lighthouse. Some believe it will in the end be an eruption closer to land from the vent called Bob, or even on land close to La Restinga.

In the end it is more likely that we will have another Effusive Lava Vent In the Sea, or to put it in short, another ELVIS.

If you are feeling really worried, or things get worse you should read the splendid article on volcano preparedness written by our resident Icelander. More volcano wisdom in that article than anywhere else, a wisdom coming out of extended experience of volcanic eruptions.

http://volcanocafe.wordpress.com/2012/06/29/icelanders-do-prepare-for-eruptions-a-personal-observation/

I would also recommend that if you feel the need to relocate yourself quickly, go to the eastern part of the Island. It should be fairly safe since there has been no activity there. In the light of things, if you are really worried, or things heat up even more, do not wait for an official call for evacuation. Just go if you can or feel the need. Remember that in the end it is you who are responsible for your decisions regarding you and your loved ones.

CARL