El Hierro Tagged ‘El Hierro’

Latest El Hierro Report

Saturday, July 19th, 2014

El Hierro Volcano activity report

Last update: July 5, 2014 at 1:41 pm by By

This is the most recent El Hierro Volcano eruption report

2014-07-05 13:34 UTC
Its about time to report the earthquakes of the last couple of weeks (Sorry Susanna). Here is the list of the preceding weeks.

Screen Shot 2014-07-05 at 15.29.15 Screen Shot 2014-07-05 at 15.29.32

from:    http://earthquake-report.com/2011/09/25/el-hierro-canary-islands-spain-volcanic-risk-alert-increased-to-yellow/

12/26 El Hierro Update

Thursday, December 26th, 2013

El Hierro Volcano activity report – Continued (mixed) upward deformation – New deformation data (Dec. 26)

Last update: December 26, 2013 at 12:10 pm by By

2013-12-26 12:07 UTC
To make the deformation graphs a bit easier to read for our readers, we have created a map showing the axis where the most lifting has been noticed until the latest incoming data. Most earthquakes did occur and continue to occur to the East and South-East of the HI08 GPS station

Screen Shot 2013-12-26 at 13.06.07

2013-12-26 11:00 UTC
IGN has just released new Ultra Rapid deformation data showing a continuous lifting in some parts and a stagnation in other parts.
The island inflates further with 1.5 cm in both HI08 (El Pinar) and HI09 (La Restinga) which brings the strongest inflation area 7 cm higher than prior to the crisis.
HI02 and HI03 (Sabinosa – El Golfo area) are stagnating or even deflating a little.
HI01 and FRON are lifting also another 1.5 cm.
Will be followed …

Screen Shot 2013-12-26 at 11.54.35

Click on this image to see the details in full size

Screen Shot 2013-12-26 at 11.55.27

Click on this image to see the details in full size

2013-12-26 09:16 UTC
Still only a few earthquakes since midnight, but this may change based on the latest data not yet included in the list.
Volcanic tremor (indicating magma movement, still deep below the island) has been recorded by many instruments on the island.
The Upwards deformation was also confirmed by the latest Involcan/Uni of Nagoya PINA GPS station. In order to reference the current deformation vs the deformations from earlier crisis, we have included the PINA Involcan/Uni of Nagoya GPS data sheet (unfortunately the Pre-2012 data is not included). The increase we witness now can indeed be called “spectacular”.

Screen Shot 2013-12-26 at 10.11.16

Screen Shot 2013-12-26 at 10.30.58

Screen Shot 2013-12-26 at 10.32.23


2013-12-25 22:58 UTC
– A very interesting new episode in the current crisis. A calm seismic period but a continued deformation, both vertical and horizontal. In earlier crisis, once the seismic unrest stopped, also the deformation leveled or stagnated. No the lifting continues in most points as the latest IGN GPS stations are showing. All this means that this crisis is not over yet and that new seismicity is evident when the island is pushed upwards. The Upwards deformation data are really spectacular (U side of the graphs) – In only 3 days HI09 (La Restinga) lifted 6 cm! and HI08 (El Pinar) 5 cm. But not only the South-Eastern side of the island was lifted, but also most of the El Golfo area with an average of 4 cm.

Screen Shot 2013-12-26 at 00.10.33

for more information, go to:    http://earthquake-report.com/2011/09/25/el-hierro-canary-islands-spain-volcanic-risk-alert-increased-to-yellow/

El Hierro Update

Tuesday, December 24th, 2013

El Hierro Volcano activity report – New seismic crisis – more deformation and shallower earthquakes

Last update: December 24, 2013 at 4:56 pm by By

2013-12-24 16:36 UTC
– It took a while before the last interesting (low frequency) earthquakes were listed, but now we see another of these earthquakes at 9 km depth (not dangerous but certainly one that IGN will zoom into).
To give our readers an idea of the epicenter of both 9 km depth earthquakes, we generated a map of the epicenter of both quakes. We are unsure about the depth (no good seafloor maps on the internet. Google earth mentions 500 to 600 meter.

Screen Shot 2013-12-24 at 17.39.36

The epicenter of the 9 km 06:17 earthquake

Screen Shot 2013-12-24 at 17.36.09

The epicenter of the 9 km 14:58 earthquake

 

2013-12-24 15:20 UTC
A typical phenomenon happened only a couple of minutes ago. A seemingly calm and weaker seismic period ends with another strong(er) earthquake (no details yet but we expect in the M3 proximity). How can this be explained : quiet simple – pressure buildup with almost no release of energy which (within an active period) ens with a stronger than usual earthquake. Also this is a low frequency earthquake! (lucky to have explained it in the 14:13 update :) )

Screen Shot 2013-12-24 at 16.23.43 Screen Shot 2013-12-24 at 16.19.38

2013-12-24 14:13 UTC
We think it should be a good idea to explain to our readers the difference in between the different types of earthquakes, as soo many earthquakes are currently occurring below the island. The (scientific) text was initially written by Tilling, et.al., 1987, Eruptions of Hawaiian Volcanoes, but is also to be used everywhere else in the world.

During inflation (lifting of the island as discussed in previous updates) the rocks become stressed, and this stress is partly relieved by increasing numbers of earthquakes, too small to be felt, but easily recorded by seismometers at Kilauea summit. These earthquakes (called short-period or tectonic) are recorded as high-frequency features on a seismograph. During deflation the stress is completely relieved. The short-period earthquakes stop, but their place is taken by low-frequency earthquakes (called long-period or volcanic), which reflect adjustments related to the movement of magma from the reservoir to finds its way to the surface. The long-period earthquakes are related to harmonic tremor, the continuous seismic record of underground magma movement. (small adjustments to the text to reflect the El Hierro event).

A low frequency earthquake which occurred this morning at 06:17

A low frequency earthquake which occurred this morning at 06:17

2013-12-24 12:49 UTC
– New stronger earthquakes and a thicker tremor line (magma intrusion)

Screen Shot 2013-12-24 at 13.50.21

2013-12-24 12:29 UTC
– The strength and frequency of the earthquakes has weakened the last couple of hours. Microseismicity is still present abundantly.

Purple square : the most recent - red squares: less than 12 hours

Purple square : the most recent – red squares: less than 12 hours

Screen Shot 2013-12-24 at 13.44.49

2013-12-24 09:50 UTC
– Relatively few earthquakes today (less than yesterday)
– some information for both ends of readers. Those on the island who merely want to live their safe live and want to enjoy tourist spending : less earthquakes. Those (almost all from other places in the world : it is not over yet.
– The seismograph image below shows a strong earthquake at 06:17. If you are looking in the list for this earthquake, you will be surprised that it is only a 2.4 Magnitude. Why such a big line on the graph then? Because of the depth of 9 km. The seismograph is the confirmation that the depth must have been true (in seismology error margins are normal – in preliminary readings).
– Some activity is taking place offshore at the east of the island.
– Magma wint gradually into a more shallow layer. It went up approx. 2 km (from 15 to 17 km towards 12 to 15 km (last 5 earthquakes).
– The seismograph image shows at the end some more tremor indicating a further intrusion of magma. These quakes are not yet showed on the list.
– De El Pinar GPS deformation data is showing a Northern deformation of nearly 2 cm. More lifting of a bout 1 cm.
– The IGN deformation data are showing a further lifting of 2 cm! on the HI09 (La Restinga) GPS and a 1 cm lifting of the El Pinar HI08 GPS. this means lesser lifting in El Pinar and more lifting in La Restinga than the prior 24 hours. These readings are confirming what we see on the seismicity map.
– In terms of safety on the short term, we are convinced that a PEVOLCA will meet soon and will publish a report afterwards. (PEVOLCA safety board of the island consisting of IGN, INVOLCAN and the local and national authorities)

from:    http://earthquake-report.com/2011/09/25/el-hierro-canary-islands-spain-volcanic-risk-alert-increased-to-yellow/

El Hierro – New Activity

Monday, March 18th, 2013

El Hierro Volcano activity report – Strong new earthquake swarm has started at El Hierro

Last update: March 18, 2013 at 3:27 pm by By

013-03-18 15:27 UTC
– Thanks to ER readers Colin, Tommy, Chris and Vinch77 who have alerted us we can bring you this “breaking News”. A very strong seismic event has started at El Hierro. Check the HT graph and volcanic earthquakes list below (in a time-frame of only 10 minutes, 9 volcanic earthquakes have been listed by IGN + more to come) :

Screen Shot 2013-03-18 at 16.21.19

Screen Shot 2013-03-18 at 16.24.58

2013-03-18 11:36 UTC
– The M3.8 earthquake which occurred yesterday to the North of Tenerife is a pure tectonic event as the hypocenter was reported at 51 km. There are more moderate tectonic earthquakes to the north of Tenerife.
– A small volcanic earthquake swarm occurred around midnight yesterday. Most of the epicenter below the central crater area of the island. No HT generated during that period. The strongest earthquakes are however visible on the CHIE graph

Screen Shot 2013-03-18 at 12.59.08

Screen Shot 2013-03-18 at 12.23.47


2013-03-16 16:52 UTC
– A short period of seismic activity near midnight earlier today.

Screen Shot 2013-03-16 at 17.48.36


2013-03-13 23:40 UTC
– The so called activity which started around 08:00 this morning ended at 18:00 UTC this evening. The same occurred yesterday. The logical explanation for this is human interference. Seismographs are very sensitive instruments and cars, people or other human activities can influence the recordings. We think this is the case here.

for more information, go to:    http://earthquake-report.com/2011/09/25/el-hierro-canary-islands-spain-volcanic-risk-alert-increased-to-yellow/

2012 Volcano Report fr/Erik Klemetti

Tuesday, January 8th, 2013

2012 Volcanic Year in Review

The submarine eruption at El Hierro continued into 2011. Image: INVOLCAN

2012, for all the hype about apocalypse, was a volcanically-quiet year. No Eyjafjallajökulls, no Puyehue-Cordon Caulles, no Pinatubos. Sure, we had some notable eruptions, but most were small-to-moderate events that, many times, won’t even end up getting preserved in the geologic record. However, that didn’t stop me from posting way too much! No, really, it was still a great year for Eruptions, with decidedly more posts about the science of volcanoes when the actual volcanic events were low. Here is the 2012 Volcanic Year in Review!

 

January

The start of the year got us starting to wonder about potential eruptions that might follow — including heightened alert at Lascar (that didn’t lead anywhere) and increasing activity at Popocatépetl (that sort of led somewhere). We also saw some of the last gasps of the submarine eruption at El Hierro in the Canary Islands, but as you’ll see, it hasn’t stopped the island from rumbling.

However, the media was caldera crazy to start 2012. Maybe it was just the tip of the Maya iceberg, but the Daily Mail opened January with a terrible article about the supposed immediate threat that Laacher See posed to Europe. The newspaper had to rescind the article come February. I dissected some of the conspiracy theories surrounding Yellowstone and we had some rumblings of two active caldera systems: Santorini and Long Valley.

I also tackled your questions about my 2011 post on falling into lava, I put together a gallery of images related to some of the many volcano observatories around the world and looked that the supposed danger (and younger age) of Ubehebe Crater in California.

February

Probably the biggest show in February was the fire fountains and lava flows from Etna during one of its many paroxysms of 2012. Not only are Etna’s eruptions spectacular, but they occur in a highly populated area – unlike the periodic dome growth and explosions that occur at Alaska’s remote Cleveland volcano or Pagan in the Mariana Islands. These volcanoes require satellites to watch them carefully to see activity when there is no one on the ground to notice it happening. Two volcanoes had small eruptions that looked like they could be leading to larger events, but neither Kanaga nor Rincón de la Vieja had much to show for 2012 when all was said and done.

After feeling a little jaded about all the “bad journalism” posts I had to tackle, I decided instead to look at why I love volcanoes (much more satisfying). February also brought some great vistas from above, including a shot of the island of Java and a multitude of volcanoes from space. I tried to explain how bubbles in magma lead to explosive eruptions and Dr. Shan de Silva answered your questions about Andean calderas.

I also tackled a topic that came up repeatedly during the year – the missing eruptions in the ice cap record. Namely, the ice cores suggest a large eruption in 1258 AD, but no source has been definitively identified (although inroads have been made). Another mysterious caldera eruption, the Kuwae caldera eruption in the 1450s, was also examined about whether it actually occurred.

March

Etna kept up its pace with another paroxysm to start the month, but for me, the real news was the unrest at Colombia’s Nevado del Ruiz. By the end of March, INGEOMINAS was expecting an eruption of the volcano near my mother’s hometown in “days to weeks.” Iliamna in Alaska also began to show unrest, with elevated seismicity that has persisted throughout the year.

One of the perks of my job at Denison is the field trips — and 2012 was no exception as I got to take students through some of the volcanic landforms of the Owens Valley in California, including Coso and the Long Valley caldera. I also looked at how hurricanes might influence volcanic eruptions after some research on Pinatubo and other subtropical/tropical volcanoes. March also saw the 30th anniversary of the eruption of El Chichón in Mexico – I looked back on the event and what might be in store at the volcano.

A March 23 image of Askja in Iceland, whose crater lake melted earlier than expected. Image: NASA.

April

Another month, another paroxysm at Etna. What we didn’t know then is that after April, activity at Etna would drop significantly. We had a little mystery in Iceland, where the crater lake at Askja was unexpectedly ice free months ahead of usual. Meanwhile, Nevado del Ruiz continued to rumble in Colombia. However, the most eyes were trained on Mexico’s Popocatépetl, where continued small explosions and seismicity prompted increased worry that a major eruption was brewing. However, as much as the volcano rumbled, nothing big came during 2012.

I tried to answer a question I get frequently: can humans trigger a volcanic eruption (short answer: maybe, but it would be hard and pointless). I also took on the quacks who try to sell bogus earthquake/eruption predictions (with some amusing backlash in the comments). I offered up a challenge to the earthquake prediction crowd, include the quackiest of the bunch, Piers Corbyn, but no one took me up on it.

May

Fuego in Guatemala was the headliner for May, producing its largest eruption in years. We also had ash from Nevado del Ruiz fall on cities close to the volcano like Manizales and Pereira. Other eruptions were so remote that only satellites caught the action, like the plume from Curry in the South Sandwich Islands.

Without a lot of other volcanic news during May, I looked at a pile of volcanic research, including the timing of caldera-forming eruptions at Yellowstone, volcanic lightning, the fate of all that volcanic ash, what to expect from the Baekdu Caldera in China/North Korea and how crystals can unravel the subvolcanic magmatism at active volcanoes.

June

Both Popocatépetl and Nevado del Ruiz kept on producing small eruptions as we headed into June, while Cleveland in Alaska had a explosive eruption, likely due to collapse of the dome that had been growing in the crater since earlier in the spring. We also saw the alert status raised at El Hierro in the Canary Islands for the first time in months after an intense seismic swarm occurred — but this swarm didn’t lead to any new eruption.

June marked the 100th anniversary of the largest explosive eruption of the 20th century – the famed Novarupta/Katmai eruption that produced the Valley of 10,000 Smokes. It was also the 1st anniversary of another significant eruption, the Puyehue-Cordón Caulle eruption in Chile/Argentina. Speaking of volcanically-active area, I decided to take a look at volcanism on Io and just how hot the surface of Jupiter’s inner moon might be.

July

July wasn’t too eventful on the volcanic front — but it definitely kept me on my toes after the 2012 Derecho knocked power out in Granville for 10 days. However, in volcano news, we began to get signs that Tongariro in New Zealand might be up to somethingseismic activity began to rise and volcanic gas emissions followed suit. Sakurajima, a fan favorite, also produced some of its larger explosions in the past few years.

I spent a lot of July on the road, mostly out in California doing labwork with my research student — but I did get to check out the Clear Lake area and saw some of California’s volcanic features from 30,000 feet. I also tackled why the volcanic rumblings in Colombia likely reflect more monitoring rather than more activity and how artificial volcanoes aren’t the cure-all for global warming.

A weather satellite image of the eruption plume from Tongariro in New Zealand. Image: NASA/NOAA/CIMSS

August

By the time August rolled in, it was becoming clear that 2012 was lining up to be a volcanically-quiet year (no matter what conspiracy fans tried to deny it). However, if you were in New Zealand in August, you wouldn’t have thought it was that quiet. Mere hours after I posted about the potential dangers of visiting White Island as a tourist, Tongariro had its first eruption on its main edifice in over 110 years. It turned out to be a minor, mostly steam-driven eruption. White Island also had a small explosive event to go with Tongariro’s … but that’s not all! A pumice raft was discovered in the Kermadec Islands north of New Zealand and eventually tracked back to a mid-July submarine eruption at the hitherto unrecognized seamount Havre. Sonar surveys later in the fall confirmed it as the source of the pumice raft as a new cone was imaged and all the pumice is still floating out in the western Pacific.

In other parts of the world, the Grozny Group in the Kuril Islands had a small explosive eruption while a small tephra cone was seen growing in the Buoco Nuovo crater at Etna.

September

Over the course of the fall, Nicaragua’s San Cristobal experienced eruptions large enough to prompt evacuations of people living near the volcano. Little Sitkin joined the parade of Alaskan volcanoes that showed signs of unrest, as a seismic swarm was noted at the remote volcano. We also saw ash from Anak Krakatau spread as far as 80 km from the island volcano — and I looked at how many people are displaced by volcanic activity in Indonesia. The future of Yellowstone caldera was the subject of a special paper in GSA Today (and guess what? It isn’t “end times”.)

In guest post at Lookout Landing, a blog about the Seattle Mariners, I discussed the potential volcanic threat Rainier poses to the Seattle/Tacoma area. I also took on the DOOOOOM that permeates media reports on volcano research — and lead me to write “A Media Guide to Volcanoes“.

October

I started October with one of my favorite satellite images of 2012 — a look down at the Three Sisters region in Oregon. In active volcanic events, the lava lake at the Halema’uma’u Crater on Kilauea reached a new high, while a new lava lake might have been spotted at the remote Indian Ocean volcano, Heard Island. We also saw a phreatic explosion at Poás in Costa Rica.

I talked about the great GSA Field Forum in the Sierra Nevada that I attended over at the GSA Speaking of Geoscience blog. My experiments with R produced a list of the most active volcanoes (in terms of >VEI 5 eruptions) during the last 10,000 years. I also looked at how to discuss models versus observations in science research and some fearmongering in the media over Salton Buttes and Newberry caldera. We also saw the unfortunate verdict of the l’Aquila trial in Italy, a verdict that could have ramifications in hazard monitoring for years.

The fissure vents from the late November eruption of Tolbachik. Image: KVERT.

November

November was the host to a number of eruptions, most prominently the second explosion of 2012 at New Zealand’s Tongariro. This came very soon after an alert from GNS Science about elevated temperatures at Ruapehu, Tongariro’s neighbor (and in all likelihood, a complete coincident). Volcanoes in Indonesia were as busy as ever while Santa Maria in Guatemala had some of its most vigorous activity in a while. A small plume was also spotted at Chirpoi in the Kuril Islands. However, the big action of November was just to the north of Chirpoi, on the Kamchatka Peninsula. In late November, Tolbachik, part of a complex of volcanoes that includes Bezymianny and Kliuchevskoi, had its first eruption in 36 years. It was an impressive fissure eruption that had produced lava flows that travels 10s of kilometers down the slopes of the volcano.

With all the excitement of the US Presidential election in early November, I looked at the perception of probability versus prognostication when it comes to volcanic mitigation. If you’re looking for a volcano movie to watch, I finally wrote up my guide to volcanic cinema and I described what a SHRIMP-RG is and how I use it in my research.

December

As 2012 drew to a close, we were greeted by the media frenzy about the supposed December 21 “Maya Apocalypse” and considering that you’re reading this, it is safe to say that the end of the world was not 12/21/12. The Tolbachik eruption went strong for much of the month, with some gorgeous lava flows that showed off all the textbook features we look for in these volcanic events. New Zealand’s White Island produced something that hasn’t been in any textbook: an odd looking spiky spine/dome in the central crater. We also got an impressive eruption from Ecuador’s Tungurahua and some evidence that active volcanism might be occurring on Venus. However, just as the year was coming to a close, Copahue on the Chile/Argentina surprised us with an unexpected eruption, sending a plume across southern South America. I closed out the year talking about why rocks melt on Earth — a useful thing to know if you’re into volcanoes!

So, there you have it. The Volcanic Year in Review … and hopefully 2013 will bring us more volcanic excitement.

 

Erik Klemetti

Erik Klemetti is an assistant professor of Geosciences at Denison University. His passion in geology is volcanoes, and he has studied them all over the world. You can follow Erik on Twitter, where you’ll get volcano news and the occasional baseball comment.

from:    http://www.wired.com/wiredscience/2013/01/2012-volcanic-year-in-review/#more-143110

Erik Klemetti on 2012 Volcanic Activity

Thursday, August 2nd, 2012

2012: A Volcanically Quiet Year (So Far)

A brief explosion from Popocatépetl in Mexico on July 21, 2012. Popo has been one of the few volcanic newsmakers of the year. Webcam capture courtesy of CENAPRED.

One topic of discussion that has come up recently on Eruptions is how volcanically quiet 2012 has been so far. Unlike the last few years where there have been multiple significant eruptions that captured people’s attention, there have not been many such events in the past 7 months. Now, this is not to say that there hasn’t been volcanic activity – there has been plenty. However, we have not seen any large eruption that has been splashed across the media since Puyehue-Cordón Caulle  last fall … and not to tempt fate, but it was noted on Twitter last night that there hasn’t been a M7 or greater earthquake since April on the planet. We still have 5 months to go, but so far 2012 has been turning out to the the opposite of the Mayan apocalypse that some people are expecting.

 

However, is 2012 anomalous? Hardly! Just like when there is a strong uptick in volcanic/earthquake activity, this lull is likely mainly due to the random distribution of volcanic events. Sometimes we get clusters of larger eruptions, sometimes we get quiet times. One quick way to look at this is to think about the number of VEI 4 or greater eruptions over the past 10 years (as a small sampling):

  • 2012: 0
  • 2011: 3* (Puyehue-Cordón Caulle, Grímsvötn, Nabro)
  • 2010: 2 (Eyjafjallajökull, Merapi)
  • 2009: 1 (Sarychev Peak)
  • 2008: 3 (Kasatochi, Okmok, Chaiten)
  • 2007: 0
  • 2006: 1 (Rabaul)
  • 2005: 1 (Manam)
  • 2004: 0
  • 2003: 0
  • 2002: 2 (Reventador, Ruang)

* Note: The estimated eruptive volumes for some of the major eruptions of 2011 are not well quantified due to their location (amongst other things). Puyehue-Cordón Caulle was clearly VEI 4+, but Nabro and Grímsvötn are, at the most, VEI 4, likely below that threshhold of 0.1 cubic km of erupted material.

So far in 2012, no eruption reaches anywhere close to the VEI 4 mark, with the most activity centered around the ever-active volcanoes such as those in the Kamchatka Peninsula (especially Karymsky, Kizimen and Shiveluch), Sakurajima, Kilauea and Santa Maria. New arrivals such as Popocatépetl and Nevado del Ruiz, have only produced minor explosions while some rumbling volcanoes such as Iliamna and Rincón de la Vieja have yet to do much of anything at all. This is all normal for the volcanoes of Earth – sometimes they have a busy years with large eruptions like in 2011 or 2008. Sometimes there are none of the larger eruptions that capture everyone’s attention, but volcanism marches on in the form of smaller eruptions that keep that heat circulating from the interior of the Earth to the surface. In the past, this might have been explained by missing data – it was surprisingly easy to “hide” an eruption – but with the increased monitoring, especially through seismic stations worldwide and satellite imagery, it is hard to imagine a large eruption going on unnoticed on Earth**.

Like I said, 2012 still has 5 months to go, so all this talk of a “quiet” volcanic year might be wiped away with a large eruption. However, just as the times of increased activity don’t suggest that the Earth is “out of control” or “heading to heightened eruptions and earthquakes” due to any number of unfounded reasons, this period of relative volcanic and seismic quiescence doesn’t mean that the Earth is doing anything different that business as usual. (And as noted on Twitter, it also doesn’t mean this is the “quiet before the storm”.)

** Note: One might argue that submarine eruptions could go unnoticed. However, a VEI 4+ would leave telltale signs as well, including pumice rafts, strong seismicity and changes in ocean temperature (locally). As an example, the very small eruption from El Hierro in 2011-12, albeit in shallower water, was easily seen from space.

P.S. 2012 has been a very active year for our closest star, the Sun. Now, I won’t go too far, but why has the Earth been so quiet tectonically when the Sun has been so active? I’ll leave that to the folks who think the Sun somehow plays the dominant role in earthquakes and eruptions.

from:    http://www.wired.com/wiredscience/2012/08/2012-a-volcanically-quiet-year-so-far/#more-123108

El Hierro Update — 6/14

Thursday, June 14th, 2012

El Hierro Volcano : Green and Yellow alert – 19 Earthquakes today, some of M 2.5+

Last update: June 14, 2012 at 2:54 pm by By

Update 14/06 – 13:00 UTC
– An increasing number of earthquakes, what is called an earthquake swarm, took place in the early hours this morning. Up to 19 earthquakes in less than 3 hours. Magnitudes have been high, with one reaching M 2.8. All  depths in between 19 and 26 km. According to IGN this is normal and part of the seismic process and not the eruption.
-Map done by AVCAN website with full list of earthquakes here:

Event Date Time Lat Lon Depth
(km)
Mag Location
1148498 14/06/2012 04:00:02 27.7251 -17.9972 20 0.5 NW EL PINAR.IHI
1148500 14/06/2012 04:32:09 27.7622 -18.0380 22 1.5 W FRONTERA.IHI
1148507 14/06/2012 04:40:20 27.7481 -18.0339 20 2.3 W FRONTERA.IHI
1148514 14/06/2012 04:46:49 27.7432 -18.0379 23 1.4 SW FRONTERA.IHI
1148515 14/06/2012 04:52:39 27.7834 -18.0411 24 1.9 NW FRONTERA.IHI
1148530 14/06/2012 04:59:27 27.7873 -18.0422 21 1.3 NW FRONTERA.IHI
1148531 14/06/2012 05:00:00 27.7596 -18.0381 26 1.4 W FRONTERA.IHI
1148542 14/06/2012 05:14:10 27.7519 -18.0415 22 1.6 W FRONTERA.IHI
1148536 14/06/2012 05:15:10 27.7306 -18.0264 22 1.9 SW FRONTERA.IHI
1148544 14/06/2012 05:22:16 27.7896 -18.0447 20 1.7 NW FRONTERA.IHI
1148546 14/06/2012 05:27:00 27.7569 -18.0432 23 1.3 W FRONTERA.IHI
1148547 14/06/2012 05:34:31 27.8004 -18.0500 19 1.3 NW FRONTERA.IHI
1148549 14/06/2012 05:34:56 27.7735 -18.0356 21 1.5 NW FRONTERA.IHI
1148559 14/06/2012 05:41:04 27.7853 -18.0509 21 1.8 NW FRONTERA.IHI
1148561 14/06/2012 05:54:22 27.8062 -18.0488 20 1.8 NW FRONTERA.IHI
1148562 14/06/2012 06:01:52 27.7644 -18.0395 22 2.3 W FRONTERA.IHI
1148563 14/06/2012 06:05:07 27.7794 -18.0525 22 2.8 NW FRONTERA.IHI
1148565 14/06/2012 06:06:20 27.7726 -18.0591 23 2.7 NW FRONTERA.IHI
1148568 14/06/2012 07:48:40 27.8015 -18.0680 21 2.1 NW FRONTERA.IHI

 


Update 13/06 – 13:00 UTC
2 Earthquakes today after 5 days without any, making a total of 36 earthquakes registered by IGN since 1st June 2012.
– The strongest at 04:57 UTC with a Magnitude 1.8 and depth 25km. At 08:10 UTC a soft movement of Magnitude 0.3 and depth unknown. Both similar location, N Frontera.


Update 10/06 – 15:00 UTC
– Following the update containing the document from ULPGC, here is the video, showing the volcano at different depth, bubbles and fish swimming along. Recorded by the Qstar Crew of the Atlantic Explorer.


Update 09/06
– Joke Volta made a summary of events for the past week which can be download here. Also, here photographs from these days can be downloaded in this zip file here.

for more information and updates, go to:    http://earthquake-report.com/2011/09/25/el-hierro-canary-islands-spain-volcanic-risk-alert-increased-to-yellow/

El Hierro Overview

Sunday, May 20th, 2012

The 2011 submarine volcanic eruption in El Hierro (Canary Islands), Spain – Eruption overview

Last update: May 18, 2012 at 6:19 pm by By 

With special thanks to Dr. Carracedo (Geovol) allowing us to publish his report and Joke Volta for facilitating.

Dr. Juan Carlos Carracedo Gómez – ULPGC

Forty years after the Teneguía Volcano (La Palma, 1971), a submarine eruption took place off the town of La Restinga, south of El Hierro, the smallest and youngest island of the Canarian Archipelago. Precursors allowed an early detection of the event and its approximate location, suggesting it was submarine. Uncertainties derived from insufficient scientific information available to the authorities during the eruption, leading to disproportionate civil protection measures, which had an impact on the island’s economy based primarily on tourism, while residents experienced extra fear and distress.

El Hierro, 1.12 million years old, is the youngest of the Canary Islands. Located at the western end of the archipelago together with the neighboring island of La Palma, El Hierro rests on a ca. 3500 m-deep ocean bed.
The principal configuration of El Hierro is controlled by a three-armed rift zone system that gives rise to three ridges that extend from the center of the island in a characteristic ‘Mercedes star’ geometry(Carracedo, 1994), and host the larger part of El Hierro’s subaerial eruptions (Fig. 1A).
This triple-armed shape of El Hierro is further enhanced by the scars of several massive gravitational landslides that truncate all three flanks. The collapse of the north flank, that formed the spectacular El Golfo bay with an almost vertical 1400 m-high escarpment, is the youngest landslide of the entire Canary Archipelago with an age of less than 100 ka. Rift zones, however, also continue underneath the sea surface. The south rift stretches as a submarine ridge for more than 40 km (Fig. 1B), indicating that recent submarine eruptions have occurred there as well.

Fig. 1. A. Geological map of El Hierro (from Carracedo et al., 2001). B. colour shaded relief image of El Hierro viewed from above (from Masson et al., 2002). The subaerial and submarine parts of the South rift are indicated.

During the German research cruise Meteor 43/1 in 1998, lava samples were dredged from the submarine prolongations of the southern rift zones of La Palma and El Hierro. El Hierro samples taken close to the present eruptive site (<3 km distant) included fresh picrites and alkali-basalts and variably altered lapillistones and hyaloclastites. Further dredging along the submarine north-west and north-east rift zones during the Poseidon 270 cruise in 2001 recovered fresh alkali basalts from 21 young volcanic cones at depths of 800 to 2300 m together with ocean bottom sediments having a strong volcaniclastic component.
It appears overall that the density of seemingly young volcanoes on El Hierro’s submarine rifts is comparable to that on land, emphasizing the relevance of submarine eruptions during the growth of oceanic islands.

Precursors to the 2011 eruption

Numerous earthquakes were recorded by the Spanish Instituto Geográfico Nacional (IGN) from July 2011 onwards, the greater part of them insignificant from a hazard point of view, but were clearly precursors of a volcanic eruption. In particular, seismicity, initially of low magnitude (M < 3.0) and focused north of the island, increased while migrating southward. The greater part of the hypocentres were initially concentrated within the lower oceanic crust (Fig. 2), at depths of 8–14 km (ca. 200–400 MPa pressure), which is in agreement with pressure estimates from microscopic fluid inclusions in xenoliths from north-western El Hierro and phenocrysts from a recent eruption. The seismic and petrological data are thus in-line with a scenario of a magma batch becoming trapped as an intrusion horizon, near the base or within the subisland oceanic crust. Shifting seismic foci suggest that magma progressively accumulated and expanded laterally in a southward direction, causing a vertical surface deformation of about 40 mm at that time.
During this initial phase, the system remained active but showed no sign of having overcome the resistance of the oceanic crust. Hypocenters thereafter migrated south-east, approaching the submarine prolongation of the active South rift zone. From there, the magma progressed rapidly towards the surface, as indicated by the first time occurrence of shallow (< 3 km) earthquakes on 9 October 2011.
The scenario changed dramatically at about 4 am on 10 October, when the now frequent and strong seismicity (up to M 4.4) ceased and was rather abruptly replaced by a continuous harmonic tremor, indicating the opening of a vent and thus the onset of a submarine eruption.

Fig. 2. Seismic hypocentres beneath El Hierro between 19 July and 10 October 2011. Hypocentres migrated from North towards the South rift zone of the island, where they became shallower (< 3 km). The eruption commenced on 10 October. Most of the time, seismicity remained stable at the base of the oceanic crust (data from IGN, http://www.ign.es/ign/resources/ volcanologia/ html/eventosHierro. html)

The submarine eruption

On October 10, patches of pale-colored water that smelled of sulfur and were associated with dead fish, were found floating one mile south of the coast confirming the opening of a vent on the flank of the submarine part of the South rift zone. The surface expression of this eruption, including green and bright discoloration of seawater, was clearly observed in high-resolution satellite images featuring a large stain(locally known as ‘la mancha’) visible on the surface of the Las Calmas Sea (Fig. 3A). The eruption formed aNE–SW trending fissure outlined by strong bubbling and degassing (Fig. 3B), occasionally 10–15 m high, loaded with juvenile volcanic ash and pyroclasts (Fig. 3C).
However, information on the depth and precise location of the submarine vent was lacking in the first two weeks of the eruption because of the unavailability of adequate means for submarine surveying.
On October 24, the RV Ramón Margalef of the Instituto Español de Oceanografía (IEO) carried out the first survey of the area, previously mapped in 1998 by the Spanish RV Hespérides (Fig. 4A). Comparison of present and 1998 bathymetry outlined a 700 m-wide, 100 m-high new volcanic cone resting at about 350 m depth in a canyon on the flank of the South Rift submarine extension (Fig. 4B). On 4 December 2011, the eruption apparently waning, the RV Ramón Margalef carried out another campaign, detecting significant growth of the volcanic edifice. The initial single eruptive center (Fig. 4A,B) had now evolved to three cones of similar height, with their summit 180–160 m below the sea surface (Fig. 4D), still below the critical value to generate significant surtseyan explosions (about 100 m below sea level).
Lava flows and pyroclasts, confined by the canyon walls, caused the greater part of the erupted volume to flow downslope towards deeper parts of the ocean floor.

Fig. 3. A. Plume of dissolved magmatic gases and suspended matter producing green and bright discolouration of seawater (locally known as ‘la mancha’) commencing on 10 October 2011 and continuing for several kilometres to the south-west before drifting off into the Atlantic (Satellite image by RapidEye). Fig. 3. B. Plumes of gas on ocean surface showing a N–S trend, indicating a submarine eruptive fissure. Inset: Expansion of steam with decreasing water depth (modified from Schmincke, 2004). C, strong degassing with abundant rock fragments generated large ‘bubbles’, some of them 10–15 m-high, bursting to the surface off the nearby village of La Restinga (8 November 2011).

 

Fig. 4. A. DEM showing the pre-eruptive submarine canyon where the 2011 eruption nested (image taken from the RV Hespérides, 1998). B. DEM of the same area taken on 24 October by the RV Ramon Margalef after the onset of underwater activity. C. Geological map of the submarine eruption from the first DEM obtained on 24 October 2011 by the RV Ramon Margalef. D. Geological map of the same area on 4 December 2011.

Floating stones off El Hierro

Abundant rock fragments resembling lava bombs on a decimeter scale (Fig. 5) and characterized by glassy basaltic crusts and white to cream-colored interiors, were found floating on the ocean surface during the first days of the eruption. The interiors of these floating rocks are glassy and vesicular (similar to pumice), with frequent mingling between the pumicelike interior and the enveloping basaltic magma (Fig. 5B).These floating rocks have become known locally as ‘restingolites’ after the nearby village of La Restinga. Their nature and origin remained elusive at first, with suggestions from the scientific community including: (1) the floating bombs are juvenile and potentially explosive high-silica magma; (2) they are fragments of marine sediment from the submarine flank of El Hierro; and (3) that they are relatively old, hydrated volcanic material. However, none of these interpretations provides a satisfying fit to the available observation since for instance, high-silica volcanism is uncommon on El Hierro, and magmatic minerals (either grown in magma or as detritus from erosion) are entirely absent in the ‘restingolites’. Given that the involvement of highly evolved, high-silica magmatism would have implications for the explosive potential of the eruption, it was important to clarify the nature of the ‘restingolites’ swiftly in order to fully assess the hazards associated with the ongoing El Hierro eruption. Furthermore, should the ‘restingolites’ be shown not to originate from high-silica magma, then unraveling their genesis will most likely provide unique insights into the volcano–magma system beneath El Hierro.
All ‘restingolite’ samples are glassy and light in color and most are macroscopically crystal-free. However, occasional quartz crystals, jasper fragments, gypsum aggregates and carbonate relicts have been identified in hand specimens. X-Ray diffractograms mainly indicate the presence of quartz, mica and/or illite, and glass. There is a notable absence of primary igneous minerals from the XRD data. Microscopic quartz crystals have also been identified and analysed using a field emission electron probe micro-analyser (FE-EPMA), as well as the composition of the glass matrix, which ranges between ~65 and 90 per cent SiO2.
The high silica content coupled with overall low incompatible trace element concentrations, the occurrence of mm-sized relict quartz crystals and the lack of igneous minerals, plus the occurrence of carbonate, clay, jasper and gypsum relicts are all  ncompatible with a purely igneous origin for the cores of the floating stones. Igneous rocks on El Hierro do not contain any free (primary) quartz crystals (nor do igneous rocks on any of the other Canary Islands).
A potential source of the quartz crystals found in the floating rocks from El Hierro is likely to be the sediments of layer 1 of the pre-island ocean crust. These contain quartz crystals transported from Africa by both wind and turbidity currents and are characterized by a lack of igneous minerals due to their pre-island age.

Fig. 5. A. ‘floating rocks’ observed in October 2011 off El Hierro. B. ‘restingolite’ sample displaying typical features, such as a crust of basalt, primary sedimentary bedding, folding, high vesicularity, and mingling structures. C. hollow basaltic bomb of the late stages of the eruption. D. similar bomb from the Serreta Oceanic Volcano, Terceira, Azores (photograph by Ulrich Küppers).

The floating rocks found at El Hierro are thus most probably the products of magma–sediment interaction beneath the volcano (Fig. 6). Ascending magma mixes with the pre-volcanic sediments and the ‘restingolites’ were carried to the ocean floor during eruption while being melted and vesiculated during transport in magma. Once erupted onto the ocean floor, some of them were able to separate from the erupting lava and floated to the sea surface due to their low density (Fig. 6).

for more information and updates, go to:    http://earthquake-report.com/2012/05/18/the-2011-submarine-volcanic-eruption-in-el-hierro-canary-islands-spain-eruption-overview/

El Hierro Update 4/29

Sunday, April 29th, 2012

El Hierro Volcano : Green and Yellow alert – eruption continuing + still dead fish above the main vent area

Last update: April 29, 2012 at 11:18 am by By 

Update 29/04 – 10:25 UTC
– A stain is present in Las Calmas sea this morning. No jacuzzi has been observed. This stain could be the remains of yesterday’s activity. Joke images will be online later today.

Update 29/04 – 10:20 UTC
– An amazing picture of the waters of the vent area which was photographed yesterday by Julio del Castillo Vivero. Colored waters with a lot of seagulls having lunch with dead fish



Update 28/04 – 23:48 UTC
As written earlier, Julio del Castillo Vivero was invited by the crew of the Atlantic Explorer to sail with them to the vent area. He wrote the following :
Hello, very good day with the Atlantic Explorer, the crew of Qstar and the scientists of ULPGC. I was above the volcano! A very special moment for me after many months following the eruption. I saw lots of seagulls above the main vent, eating dead fish, around the size of 10cm that was emerging to the surface.
The stain was very clearly visible today from the boat, with a green color, not super strong concentrated as used to, but quite clear.
I didn’t get seasick at all, it was very good. Sea was calm in the morning and then also sunny from midday.
Great day! Great people! Great images!
(ER : strange that there are still dead fish above the main vent – we also noticed on Jokes pictures in the middle of the week that a lot of seagulls were flying above the vent area.
The news coming in from the Atlantic Explorer is even more important as Joke has not seen any action in the sea today, which means that the volcano can erupt without a clear visual sign on the outside. Good to know is that seagulls on the vent area are indicating dead fish and thus erupting material and that a stain clearly indicates action which is more than degassing)

Update 28/04 – 22:55 UTC
– 1 additional earthquake today and if not revised , extremely shallow at 1 kmMagnitude 1.0. Time 21:32.Epicenter in El Golfo

Update 28/04 – 13:17 UTC
 1 earthquake since midnight. A M1.4 magnitude quake at a depth of 15 km on this location
– Julio del Castillo Vivero is on board of the Atlantic Explorer. Luckily for him the sea is calm reports Joke (an Ocean swell is even with calm weather often enough to get seasick!).  Let’s hope that Julio will have some nice pictures later today. The ROV will not be used today as the people on board of the ship have a bunch of other tasks. Julio has send the image below from the ship a little earlier. It shows the volcano cone at his present depth. We will have to wait until tonight to find out what the colors really mean.
I  a direct message to us, Julio writes : ERUPTION STILL ONGOING

Image made by Julio del Castillo Vivero on board of the Qstar Atlantic Explorer today

for more images, updates, and information go to:    http://earthquake-report.com/2011/09/25/el-hierro-canary-islands-spain-volcanic-risk-alert-increased-to-yellow/

El Hierro Update

Monday, March 19th, 2012

El Hierro Volcano : Yellow alert – Images of Glowing Lava at 70 meter depth

Last update: March 19, 2012 at 6:41 pm by By 

VERY IMPORTANT Update 19/03 – 17:02 UTC
– ER reader Roland (see comments) has given us the lead to a report of the University of Las Palmas de Gran Canaria showing the still erupting submarine El Hierro volcano with glowing lava seen floating at a depth of 70 meter.
What nobody could accomplish so far, has been done by the ROV E-Wally on board of the SOS-OceanosQ-StarAtlantic Explorer ship by the scientists of the Universidad de Las Palmas the Gran Canaria.
– The images have been captured on March 14 as the date on the images reveal. The images are of course foggy as a lot of suspended material is polluting the water.
– No doubt that Q-Star and the University has also some video footage that they will probably release later on (the pictures are probably screen captures of the video).
We are however VERY PLEASED that all those who cooperated on this mission have proved that the eruptive process is not yet entirely finished (at least it was not after the date that Pevolca said that the eruption stopped).

Original images courtesy Q-Star and Universidad de Las Palmas de Gran Canaria

ER manipulation of the color saturation and contrast from the original picture above, a lot more details are appearing

 

Image Courtesy Q-Star and Universidad de Las Palmas de Gran Canaria

Update 19/03 – 16:00 UTC
– Images of Joke Volta of today March 19

Update 19/03 – 11:17 UTC
– Nothing unusual this morning.
– Since midnight NO listed earthquakes since Saturday
– Sunday afternoon we noticed increased microseismicity. The variation in HT signal is often caused by changes in tide, wind, waves etc, external factors which have nothing linked to the eruption. However, a minimal HT is still present.
– Joke continues taking her daily pictures, with of course more focus to the island itself these days. She does not want to give up right now as the eruption might get stronger again.

for more information and updates, go to:    http://earthquake-report.com/2011/09/25/el-hierro-canary-islands-spain-volcanic-risk-alert-increased-to-yellow/