El Hierro / Canary Islands - Most Recent Information By The Most Diligent - And Recap Of Past Year

i don't think they're at a loss. i think they know EXACTLY what is happening!

This was posted by Judith on Volcano cafe...

Latest deformation reports from Involcan.

,,Recent GPS data processed by INVOLCAN and the Nagoya University researchers show significant changes after the new seismic episode. In the image you can see the evolution in the station located in La Restinga. This has shifted from September 13th 1.34 cm horizontally, with a South-East direction and has also promoted 4.81 cm vertical,,

[link to m.facebook.com]

tick tock..

[link to picasion.com]

that 4.8 is almost 2 inches!

Hi AT, I think you may want to take a look at this...A new post has just been posted on Volcano Cafe...Interesting to say the least..

El Hierro : a tectonic compression/relaxation mechanism?

Hypothesis: the earthquake swarms report relaxation of accumulated, compressive tectonic stresses

Read the full posting here:
[link to volcanocafe.wordpress.com]


Would of posted snippets but it is way to much information to post on here. Hopefully someone can dig the Juicy bits out though and post them....

Thanks...here's what catches me:

"The crust under the Canaries, part of the African tectonic plate, is moving north eastwards at 24mm annually in response to drag from the upper mantle."

That would explain some of the quakes however, we've seen 24mm of movement in ONE DAY during these swarms!!!!

"This compressive stress accumulation must be almost silent to seismometers: very few earthquakes have been recorded at Hierro over 25 years prior to 2011."

So...Hierro has begun a phase...something that has not occured in the thousands of years it has been there and it is not stopping. I think this one sentence right here verifies that Hierro is on the road to something substancial and frankly...unpredictable.

"It is the sudden relaxation of accumulated compressive stress that causes the earthquakes. The earthquake swarms are proposed to result from relaxation of compressive stress."

I don't agree with this concept. Show me how the progressive stress is reduced in some measurable capacity and then maybe I'll buy it. The plate doesn't just stop compressing...unless it's overall movement is finally over. Which...the rest of the article does not specify.

What I could buy is that the bulk plate and the surface plate might be finding a way to relax from their movement from each other. What's really interesting is to consider that this archipelago's bulk plate seems to be filtering ativity ONLY towards Hierro and the stress relaxation is offset by sudden deep, sometimes very deep, quakes around the Tenerife/Grand Canary island. We also saw one at 79km deep north east of La Palma a few days ago. That to say the least was interesting...that quake would've been BELOW the mantle...in the core!

Their imagery on #8, and without their actual explanation, may explain why the Frontera Bay region has seen most of the landslides. All the pressure is pushing forwards on the island. However, that also means that at some point the underside of the south can buckle and do a barber chair. It can become so unstable at the water line that it breaks and rolls outwards, causing a reverse slide.




THanks for the link and the info. THat was a great read! :)

You have some great valid points AT...You should register on VC and have your say, you could be a great contributor on there....

What I do have to say to people on GLP is this....

The article posted is just a 'Theory'. It is no way a 100% true account as to what is happening at El Hierro until it is proven 100% correct....

The writer is theorising as to what he thinks MAY be happening at El Hierro due to some of the data he has collected and the lack of Harmonic tremors when we all thought magma was rising...

Nevertheless, it is another great theory that can be added to the list to ponder when we get more data and events in the future....

Good Morning all!

2012-09-20 07:51

- 4 earthquakes so far today – 3 at +20 km, 1 at 10 km
- Deformations : In the vertical component, Frontera and Restinga are showing a very strong (2 cm) deflation. Pinar is almost stabilized. This makes a totally different picture than yesterday. It confirms that the swarm is over again but the total uplifting of the island can still be called extraordinary.

[link to earthquake-report.com]

below the crust in the mantle i think you meant?

There's the quake between Tenerife and Grand Canary that I was forecasting. [link to www.ign.es] And look...there was a REALLY deep quake off Hierro's Western point. 60km deep! That's actually the deepest I've seen on Hierro I believe. [link to www.ign.es]

A mess of shallow quakes are showing up!



21/09/2012

06:37:16

27.7745

-18.0854

10



1.5

mbLg

W FRONTERA.IHI




21/09/2012

06:25:51

27.7506

-18.0758

3



1.8

mbLg

W FRONTERA.IHI




[link to www.ign.es]

Good morning.

AmerTrap.....stop staying up all night.....get some rest, man. lol

2012-09-21 07:24

Yesterday was still good for 19 earthquakes, thats 4 more than our latest update yesterday. Depths were 17, 10, 21 and 10 km. All of the quakes had weak Magnitudes.

- During the latest swarm, IGN only listed earthquakes M1.5 or higher. Now that events are calming down, they have returned to a full report including the weak ones.

- 7 earthquakes listed so far today. Seismicity is back in the El Golfo area. The source for these (magmatic) earthquakes must be a fissure feeder in the crust getting resistance at a 9 to 11 km depth. The crack is currently not big enough to create more pressure as most of the earthquakes remain limited in strength.

- GPS Deformations (Dr. Sagiya) :
Restinga : After a strong vertical decrease in the Ultra Rapid data yesterday, the Rapid data (improved data) made the decrease even bigger (1.5 cm to 2 cm). Today, we are up again with a few mm in the Ultra Rapid data (Rapid data are provided many hours later). No horizontal change. We do not detect any direct relation with seismicity as the Las Calmas area had no serious seismicity during the last 24 hours.
Pinar : Deflation of approx. 1 cm. Probable reason : the central island activity started to subside yesterday and has almost completely disappeared today.
Frontera : After a strong verticcal decrease yesterday (2 cm), Frontera station was 1 cm uplifted today. This is evident, as seismicity has returned in the El Golfo area (9 to 11 km depth).
Current deformations are bad news for the people living in the El Golfo area as the process still continues below their area. There is however no direct danger as this pattern is known from the pre-swarm weeks.
Fluctuations of 1 cm up and down are fairly normal during the preceding months. In other words hard to tell whether changes are just normal fluctuations or deformations based on the current seismicity patterns.

[link to earthquake-report.com]

Last Edited by shenue on 09/21/2012 07:25 AM

I'm doing it again :) lol

THe boldened, italiced wording up there in green is really interesting...that's what eruption will come from...significant deformation.

I agree that is most interesting. That's why I bolded the GPS header. I was hoping you'd stop in and read it and give us your thoughts on it.

I could tell by the posting timestamps that you were posting during your night hours again. :-Þ

12-09-21 12:39

"Here we go again

- 14 more earthquakes since our latest update and to our surprise a lot of single digit depths. - One of these quakes was at a depth of 3 km but this quake may have been generated by deformation stress as no other quakes were triggered in the same layer.
- A lot of these quakes were weak volcanic earthquakes
- These new events will hardly have been felt by local people because of the combination Magnitude / depth, but must be certainly worrisome for those living in the El Golfo area.
- We truly hope that the analysis Involcan reported to have stopped have been picked up by IGN as people in the area should be informed in-depth of what is happening. In a normal volcanic environment, the potential eruption area is very well known, but in El Hierro’s case, only the follow up of seismicity, deformation and sampling will lead to the prediction of an eruption spot.
- We are sure that the IGN volcanologists are following up the events continuously as the past events (swarms from June and last week) have proofed that events can start in a couple of hours and reach high numbers of quakes in less than 24 hours.
- The Avcan epicenter maps below are showing a high concentration of epicenters near the beach in the Sabinosa sector. We know that IGN has a lot of equipment installed in this sector".

[link to earthquake-report.com]

Last Edited by shenue on 09/21/2012 12:42 PM

deformation stress is not something i wanted to hear

[link to imageshack.us]

^^ i put the rough upwards measurements on the map of el hierro. click on the image to enlarge it

all data taken from..

[link to www.ign.es]

i wonder what data would be on the three charts 'not working' at the moment?

in the region of the cliffs has been the greatest uplift, with less and less uplift the further north east you go

now, what we need to find out is what is the failure strength of erupted and cooled basalt, in contact with the material which was on the slope when it was erupted on top of it.

[link to picasion.com]

we know the slope below those cliffs is 25 degrees steep and that these cliffs are one of three in the Canaries KNOWN to be at risk of collapse.

how much more uplift will it take, or will it go when DEFLATION begins? there are some incredible forces at work here

i would think it's pretty much certain that should the eruption actually come up through those cliffs it will dislodge them?

This deformation is precisely why Hierro is so important to watch. In so many other areas the quakes are much larger...in the 4's and 5's...and they don't seem to produce any real activity...but here...even the 1's and 2's are causing significant uplift. The mockers and naysayers come in here and call our thread BS and what not...and it really shows how foolish and ignorant they are. We see this science...and we see that it is spelling potential for very real disaster. And...the longer it takes to finally go off...the higher the possibility that it is going to be extremely dangerous.

Earlier this year we read in the other thread about how the Canaries have sometimes changed what type of volcano they are. In fact, some of the lava that erupted from Hierro last year was decidely NOT basaltic material but instead, a hybrid of at least two types of magma. This is also probably the reason there were so many underground explosions going for a month or two...the magmas weren't getting along down there :)

Good Morning All!

2012-09-22 11:04 UTC

- 3 new earthquakes in mixed depth layers as you can see below.
- the last 10 epicenters are showing a mixed picture
- we do see again some earthquakes in the southern part of the island and in the Las Calmas sea. These earthquakes are situated in the 18 to 22 km depth zone
- for those people only following this site recently : last years eruption (colouring of the water, poisonous magma, floating lava, etc (see our first 30 parts below) was approx.. at the southernmost epicenter on the map below


2012-09-22 10:17 UTC

A word from Joke Volta, yes still living on the island and worried even more than before :

Hello everybody…this must be the longest volcano reporting of the world…
For instance last week, activity was coming up, and reaching levels of about 200 quakes a day (198 te be exact)
A very short period, and a lot of quakes, if you compare it to what happened in June this year.
I was really worried, but the situation is still the same, go on with watching because yesterday’s swarm in the Golfo-bay-area was shallow again (other active spot). Let’s not forget the deformation, must be hugh forces, to lift up the island this way…
So…we go on reporting, wishing you all a nice weekend.
Be patient … geological procedures can be last a long time …
Joke Volta


2012-09-22 05:46 UTC

GPS Deformations (vertical) : Restinga station lifted 0.5 cm and Pinar a few mm, Frontera on the other hand deflated approx. 1 cm.


2012-09-22 05:32 UTC

- September 21 ended with 25 earthquakes. A M1.1 at a depth of 23 km and a M1.5 at a depth of 8 km.
- 3 earthquakes so far today

[link to earthquake-report.com]

What an uneasy feeling...at least in California I can drive east and still be on steady ground. Out there on an island...you better know how to swim or have a fast boat!

wouldn't the different uplifts recorded on different parts of the island back the pore pressurisation theory?

if this was that magma, 20 KM down doing this, surely the whole island would uplift by the same amounts roughly, but the facts some are uplifting more than others suggests to me pockets of pressurisations in the volcano?

I want to try and answer this for you. This is only my opinion. It's my theory and so far it has been proven true several times on Hierro, but there may be something else out there that I'm not aware of or considering. Anyway...let me explain it like this.



Definitions of:

Pressurisation

1. To maintain normal air pressure
2. To put (gas or liquid) under a greater than normal pressure
3. To resist pressure
4. To pressure-cook
5. To subject to excessive stress or strain


It would appear as though you're trying to separate the idea of magma from the idea of pressurisation when in fact it is one in the same; one causes the other. The magma is what is causing the pressure to occur. But it's not not JUST magma. As magma encounters natural gases, water, crude oil, etc., it will either consume that item or it will use it to produce exhaust or upon contact it produces an air gas such as steam from encountering water, etc. Not to mention, heat expands. So...as large groups of magma gets surged under the Island, the natural heat it brings with it will cause expansion as well.

Now...I think maybe what will help you see the big picture is to understand there's not JUST a lake of magma at 20km or shallower under the island. There are huge pools of it no doubt, but there are also crevices, fractures in the rock, underground water ways, oil beds, natural gas pockets, fissures, and other types of cracks and seams in the earth beneath Hierro. So, as one of those fills up, the terrain above that immediate area expands. This is why we don't see the entire island rising all at once, and instead just see unique areas expanding. The ground adjacent and above the actual fissure or crack that is now filled with new incursions of magma will rise when the magma creates stress and pressure. Sometimes what we see when the elevation changes side to side is a large thin wall of magma has moved in somewhere and it is causing part of the island to move sideways. When the elevation drops it's normally because whatever the magma ate is now gone and the ground can settle OR the magma settles and/or moves to another area and the once expanded ground now settles back or even falls a little below zero.

There will be no ground deformation without magma incursions, water escaping through fracking caused by human drilling, or via fault movements. There aren't any known fault lines moving through Hierro besides the miniature ones caused by the previous magma intrusions. So...this is pretty much left to magma to cause these deformations.

yes, pore pressurisation!

exactly what is needed to make el julan slip!

THAT'S what i'm saying!

I know magma is causing it, but the fact is it is STILL very deep. I think it's heating the entire volcanic edifice above it, but, because el hierro is much like la palma, solid dykes of basalt and loose volcanic material in between, the bits in between are PRESSURISING, and that is the trigger!

a magma chamber 20 km below the volcano SHOULD bulge up the entire area by a consistent amount in my opinion, but the fact some areas are rising more than others suggests to me trouble is brewing

just me wild guessing, that's all.

Do you have a reference point to show that there IS a magma pool at 20km deep? In all the time we've been watching this (over a year), I've never seen any piece of evidence to show that there is in fact a pool of magma down there. I've only seen evidence pointing towards a spear coming up through the center of the island and then the crevices and cracks. If there IS a pool of magma down there it would really change the ideaology of those following the events.

I know what you mean. I keep thinking about those towering 4000 ft. cliffs right over the towns.

2012-09-22 20:52 UTC

- 3 more earthquakes this afternoon
- we have the impression that the magma in the El Golfo area has found some cracks to infiltrate in the 7 to 8 km depth layers. Last week, only sporadic earthquakes were noticed at less than 10 km.

2012-09-22 17:10 UTC

+ 2 more earthquakes, the first being a M1.6 and the second a M1.0 both at a depth of 21 km