[breaking] Vulkaanuitbarsting bij Canarische Eilanden

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Recordaantal aardbevingen op Canarisch eiland

Nog nooit eerder werden er zoveel aardbevingen achter elkaar geregistreerd op het kleine vulkanische eilandje El Hierro, het kleinste van de Canarische Eilanden. De reeks van maar liefst 720 bevinkjes heeft de overheid van deze eilandengroep voor de kust van West Afrika ertoe doen besluiten om voor het eerst in de geschiedenis een vergadering bijeen te roepen van het Stuurcomité van Vulkanische Monitoring. Dit comité werd opgericht om specifieke plannen te realiseren, die de burgerbevolking dienen te beschermen en noodplannen voor vulkanische risico’s moeten ontwikkelen. Inmiddels wordt gesproken over een ‘significante dreiging van seismische activiteit’.

Het Nationaal Geografisch Instituut (IGN) en het Volcanologische Instituut van de Canarische eilanden blijft nauwlettend de aardbevingen in de gaten houden, waarvan de kracht van de bevingen (elke dag!) ligt tussen de 1 en 3 op de Richterschaal. De meerderheid van de bevingen vindt plaats tussen 5 en 15 km diepte.

Volgens de autoriteiten betekent deze seismische activiteit nog niet direct dat een grotere, significante aardbeving zal plaatsvinden. Het merendeel van de bevingen die zijn geregistreerd, vonden plaats in het Noord Westen van het 280 vierkante kilometer kleine eilandje, bij het plaatsje El Golfo (zie foto hieronder). Een aardbeving op deze plaats zorgde er zo’n 50.000 jaar geleden voor, dat er een enorme landverschuiving plaatsvond, waarbij de helft van de vulkaan in zee gleed. Hierdoor ontstond een ca. 100 meter hoge tsunami die naar de overzijde van de Atlantische oceaan zou zijn gegleden. Schuin tegenover dit eilandje, in het verlengde van de resterende halve kratermond, ligt het Noord Amerikaanse continent..

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El Hierro Earthquake Swarm Enters Third Week
The intensity of earthquakes recorded on the smallest of the Canary Islands, El Hierro, has increased slightly during the last 24 hours. However, the total number of earthquakes recorded daily has lessened since the earthquake swarm initially began on 17 July.

The total number of tremors recorded during the past two weeks has now exceeded 1,050, according to the Instituto Geografico Nacional (IGN).

The majority of the earth tremors ranged between 1-2 magnitude, but during the past 24 hours there have been least five tremors measuring in excess of 2.0 magnitude on the Richter Scale. A 2.4 magnitude earthquake was recorded at 4:56 p.m. local time on Sunday (31 July 2011).

Approximately 50 earth tremors were recorded on Sunday, according to local earthquake monitoring agency Actualidad Volcánica de Canarias (AVCAN). The number is slightly down on the number of tremors recorded on Saturday and significantly less than the 195 earthquakes recorded on 22 July.

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The vast majority of the tremors have been recorded in the northwest of the 278.5-square-kilometre island at El Golfo, the location of a massive landslide that created a 100-metre high tsunami almost 50,000 years ago.

The earthquake swarm, prompted the Canary Islands Government to convene the first ever meeting on 22 July of the Steering Committee and Volcanic Monitoring, reflected in the Specific Plan Protection Civil and Emergency for Volcanic Risk, given what it described “the significant increase in seismic activity”. The Committee met again on Friday 29 July to discuss the low magnitude seismic activity. It reported that it had stepped up its seismic monitoring operations to identify the source of the earthquakes.

Following an evaluation of seismic and volcanological information gathered by the IGN and volcanological Institute of the Canary Islands, the Committee agreed to activate “monitoring and surveillance mechanisms necessary to coordinate the actions of civilian self-protection and information to people listed in the Plan” (translated from Spanish press release). It remains unclear, however, if the unprecedented seismic activitiy on El Hierro is a precursor to a possible future increase in earthquake or volcanic activity.

Earthquake swarms are events where a local area experiences sequences of many earthquakes striking in a relatively short period of time. The length of time used to define the swarm itself varies, but the United States Geological Survey (USGS) points out that an event may last for days, weeks, or months.

El Hierro’s Volcanic/Seismic Past

El Hierro is situated in the most southwestern extreme of the Canaries. The island was formed 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 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.

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The Swarm of earthquakes which started during July of 2011 have continued into August with 3277 earthquakes being recorded since August 1st 2011 until 23rd August 2011, this is a significant rise of earthquakes and has Experts keeping a close eye on the island.

The news may have lost interest when the swarm started in early July with over 1300 earthquakes being recorded for the month which was a huge increase in activity compared to the average 300 micro-quakes the area experiences a month.

But burying these facts wont make it go away, as figures and records show it is getting much worse with already 3277 Earthquakes being recorded in just the past 23 days. These are the figures that should cover the whole YEAR not 23 DAYS.

2010 the area registered 3661 earthquakes for the year.
2009 the area registered 4536 earthquakes for the year.
2008 the area registered 5158 earthquakes for the year.
2007 the area registered 5384 earthquakes for the year.
2006 the area registered 3689 earthquakes for the year.
2005 the area registered 4229 earthquakes for the year.

For 2011 the total stands at 6614, of which 4617 have happened in just the past 7 weeks.

2010 eruptions of Eyjafjallajökull saw thousands of Micro-quakes prior to the Eruption of this volcano.

(A microearthquake (or microquake) is a very low intensity earthquake which is usually three or less on the Richter scale. Microquakes occur often near volcanoes as they approach an eruption, and frequently in certain regions exploited for geothermal energy)

El Hierro Volcano: Is one of the Smallest of the Canary Islands, 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 cracked into a three pointed star releasing flows of Magma.

After 3 Eruptions, the island emerged from the ocean as an imposing volcano more than 2,000 Meters high.

It has now been over 200 years since the last Eruption but El Hierro although being the smallest Island has the Largest number of Volcanoes with over 500 open Sky Cones and another 300 covered by the most recent outflows.

There has been uncertainty surrounding reports of a historical eruption taking place in 1793.

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Op woensdag 24 augustus 2011 12:51 schreef zenkelly het volgende:

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Zowel het eilandje El Hierro, maar sinds maandag ook Gran Canaria zelf, dus. Ik heb het idee, dat het hier om 2 verschillende epi-centra gaat?

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Magma under El Hierro building up?
Well, we've been wondering when we might see more signs of magma rising underneath El Hierro in the Canary Island and now we seem to have got some. Over the last month, the island/volcano has experienced thousands of earthquakes that have waxed and waned in number, but seem to be increasing over time. A GPS survey of the area effected by the earthquakes has now found deformation - namely inflation - over part of the volcano. This inflation is on the order of ~1 cm over the last 20-25 days according to the Instituto Volcanologico de Canarias. There are also slightly increased carbon dioxide and temperature (above background) at the volcano as well. All of these signs add to up new magma rising in the volcano -

So the big question becomes "does this mean an eruption is around the corner?" Well, my answer to that is a resounding "maybe". Sure, these are all signs of magma emplacement, but there is likely as much chance of it all "stalling" in the crust as an eruption occurring. It will be how these factors - earthquakes, deformation, gas emissions, temperature - change over the next weeks to months that will give us a better idea of whether we will see the first documented eruption at El Hierro since 550 B.C. (or 1793 A.D., depends on if you trust the historical reports from the late 18th century).

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El Hierro: 6200 seismic events until 7 September
The Spanish Geographic Institute (IGN) reported that since 16 July, seismicity at Hierro was high above the background levels. Until 7 September more than 6,200 events had been located, most of them in the El Golfo area with hypocenters that were 10 km deep, all magnitudes were below 3. The seismic activity alternated between relatively calm periods and high-energy periods. GPS local network stations showed deformations of about 2 cm. High rates of carbon dioxide flux were measured in the anomalous area.

Geologic Summary.

The triangular island of Hierro is the SW-most and least studied of the Canary Islands. The massive Hierro shield volcano is truncated by a large NW-facing escarpment formed as a result of gravitational collapse of El Golfo volcano about 130,000 years ago. The steep-sided 1500-m-high scarp towers above a low lava platform bordering 12-km-wide El Golfo Bay, and three other large submarine landslide deposits occur to the SW and SE. Three prominent rifts oriented NW, NE, and south at 120 degree angles form prominent topographic ridges. The subaerial portion of the volcano consists of flat-lying Quaternary basaltic and trachybasaltic lava flows and tuffs capped by numerous young cinder cones and lava flows. Holocene cones and flows are found both on the outer flanks and in the El Golfo depression. Hierro contains the greatest concentration of young vents in the Canary Islands. Uncertainty surrounds the report of an historical eruption in 1793.

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Canary Islands: The local authorities at El Hierro have raised the alert status to yellow based on increased seismicity - both in terms of number of earthquakes and intensity, some earthquakes as large as M3. This new level of alert (spanish) means that the government of the island will release regular updates on the activity and make sure that appropriate emergency measures are in place.

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Op maandag 26 september 2011 09:10 schreef Ivo1986 het volgende:

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Denk je dat half Europa weg geblazen wordt?

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Island of El Hierro Prepares for possible Volcanic Eruption
The island of El Hierro in the Spanish Canary Islands is bracing itself for a possible volcanic eruption.

Situated in the Atlantic Ocean off the west coast of Africa, the Canary Islands are all volcanic, but there has been no volcanic activity on El Hierro since 1793.

However, a series of small earthquakes have been registered by sensors in the past two months and a quake of grade 3 on the Richter Scale registered last Thursday have caused the threat of volcanic activity to be raised from green to yellow for the first time in recent history.

Saturday produced another stronger tremor of 3.4 on the Richter scale which was felt all over the island.

Speaking to the El Pais newspaper, volcanologist, Juan Carlos Carracedo admitted an eruption on El Hierro would not be a major surprise.

"It is the youngest of the Canary Islands," he explained. "There is a ball of magma which is rising to the surface and it is stationed at the limit of the earth's crust. At the moment we do not know if that ball of magna will break the crust and cause an eruption."

Rather than having one large crater, the volcano on el Hierro consists of around 250 small craters.

"Any eruption would form cones on the high zones of the island and lava flows which would flow to the sea, although they would do so at a speed that would be slow enough for the population to be evacuated. It is something that could happen in days, weeks or months," said Carracedo.

El Hierro currently has a population of around 10,000 and regional government officials have begun informing them of evacuation protocols in case the worst should happen.

The last volcanic eruption in the Canary Islands took place on the island of La Palma in 1971, while the mainland town of Lorca was devastated by an earthquake of 5.2 on the Richter scale in May this year.

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Situation worsens at El Hierro. 3,5 event widely felt, 5 events over 2,5 in the last 2 hours. #Volcano

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Op dinsdag 27 september 2011 18:50 schreef spijkerbroek het volgende:
Op 1 oktober ga ik naar Gran Canaria.. ik zal m'n survivalkit maar meenemen

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2011-09-27 17:02:59.2 34min ago 27.68 N 18.06 W 14 3.4 CANARY ISLANDS, SPAIN REGION
2011-09-27 16:04:22.31hr 32min ago 27.63 N 18.06 W 11 2.6 CANARY ISLANDS, SPAIN REGION
2011-09-27 15:44:14.11hr 53min ago 27.68 N 18.08 W 17 3.8 CANARY ISLANDS, SPAIN REGION
2011-09-27 14:59:19.02hr 37min ago 27.68 N 18.07 W 16 2.5 CANARY ISLANDS, SPAIN REGION
2011-09-27 14:38:45.02hr 58min ago 27.59 N 17.99 W 11 3.6 CANARY ISLANDS, SPAIN REGION
2011-09-27 14:27:55.03hr 09min ago 27.68 N 18.08 W 17 2.6 CANARY ISLANDS, SPAIN REGION
2011-09-27 14:18:48.93hr 18min ago 27.63 N 18.02 W 13 2.7 CANARY ISLANDS, SPAIN REGION

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53 evacuated as seismic activity continues in Spanish island

MADRID (Xinhua) -- A total of 53 people were evacuated from their homes on the Spanish island of El Hierro on Tuesday night due to seismic activity in the area.

The evacuees were sheltered in school buildings or other relatives' homes in safe areas.

In recent days, there has been increased seismic activity, raising fears of the first volcanic eruption on the island since 1793.


There have been over 8,000 tremors registered since July. Although the vast majority of them have gone unnoticed by inhabitants, they have recently increased in intensity, tremors last week measuring 3.0 and 3.4 on the Richter scale.


The threat of volcanic activity on the island was raised from green to yellow for the first time in recent history and 32 more tremors were registered on Monday, the strongest of them being 2.0 on the Richter scale.


El Hierro, part of the Canary Islands in the Atlantic Ocean, is situated off the west coast of Africa and has a population of around 10,000. The recent seismic activity is thought to be caused by a ball of magma -- or molten rock -- pushing upwards beneath the earth's crust.

Instead of having one large crater, the volcano on El Hierro consists of 250 smaller craters. If an eruption did occur, lava would escape from these vents and flow towards the sea. A single explosive event, such as that experienced in Mount St Helens in 1980, is not expected by geologists.

This May, the Spanish mainland was hit by an 5.1 earthquake that took 10 lives and devastated buildings in Lorca in the south-west of the country.

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Scale of earthquakes seems to calm down
The Canary Islands Government and the Cabildo de El Hierro have decided Wednesday night that the schools of the island on Thursday resume normal activity, in view of recent scientific reports indicate that the scale of earthquakes seems to have slowed and has entered a stationary phase.

However, it will be closed to traffic, risk of landslides, the tunnel that connects the island's capital, Valverde, to the valley of the Gulf (north), the most affected by earthquakes, as reported by the director general Security and Emergency of the Canarian Government, Juan Manuel Santana.

This required to change school bus routes, so that children in the municipality of Frontera Valverde studying in his school reach across the top of the island.

The half a hundred people on Tuesday were evicted from their homes in the town of Frontera spend another night outside their homes (most are staying with family and only a dozen remain in the dorm Valverde), but tomorrow review your situation and decide whether they can return.

This was noted by the President of the Cabildo, Alpidio Armas, who has stressed that the islanders will have to learn to live with the situation presented in El Hierro from mid-July, a period in which the island has been rocked by more than 8,000 low-intensity earthquakes of volcanic origin, most imperceptible.

"This is a topic that we will have to learn to live, if not stopped. We're going to have to integrate into our lives, peace and responsibility," added Armas.

The chairman of the council has insisted the message of tranquility that all authorities have been saying for days and stressed that the scientific reports indicate that the situation appears to have entered a stationary phase.

In the same vein, Santana pointed out that such events are cyclical seismic events caused by the pressure of magma in the subsurface, so that "fall within the normal." In fact, the volcanic risk in light of El Hierro is still located in yellow, in a situation of "pre-alert."

The Director General of Security of the Canarian Government has also explained that the latest information available indicates that the focus of the earthquake is shifting to the south of the island.

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The Canary Islands government radio alert to all operators of the impending El Hierro volcanic eruption

The Canary Islands government radio alert to all operators of the impending El Hierro volcanic eruption on the island 12 kilometers

Scientists believe that in the next few hours can produce a 99% chance of eruption

Measurements and forecasts made by scientists on the island of El Hierro and the whole structure of IGN have pointed to the competent authorities within the Pevolca activated by the Canarian Government to the volcanic eruption is expected for several days can occur in next few hours at a point in the sea to twelve miles off the coast southwest of the island, which correspond to the town of Frontera.

The odds set by these scientists have risen to 99%, giving the reason Carracedo, which set the deadline for its experience and professional expertise long before any of that until now have come to the public.

In order not to alarm the population is deciding when to make public a statement giving an account of this incident, but was ordered by radio high alert all operators to be prepared, especially in the EMU and its device that includes a shelter for 2,000 people, if it is considered that the entire population evacuated.

At this time the technicians of the Canary Islands from the Cecoi El Hierro are already coordinating emergency resources and security and all air and sea operating when the eruption occurs.

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Vulkaan op Canarisch eiland staat op uitbarsten

Het Spaanse Canarische eiland El Hierro kreeg sinds 19 juli al duizenden aardbevingen te verwerken, waardoor magma naar het aardoppervlak geduwd wordt. Er wordt dan ook gevreesd dat het tot een vulkaanuitbarsting komt. Lokale functionarissen deelden woensdag nog mee dat meer dan vijftig personen uit het noordelijke dorp Frontera werden geëvacueerd uit angst voor aardverschuivingen.
Het leeuwendeel van de aardbevingen waren te zwak om door de eilandbewoners opgemerkt te worden, maar ze namen wel steeds toe in frequentie en intensiteit. Gisteren werden meer dan 100 trillingen opgetekend, waarvan de sterkste 3,8 op de magnitudeschaal haalde. Vandaag volgden opnieuw tientallen bevingen, waardoor de belangrijkste wegentunnel van het eiland werd afgesloten en honderden schoolkinderen thuis moesten blijven.

Op het eiland bevindt zich ook één grote vulkaan en ongeveer 250 kraters. De autoriteiten zien echter geen dreigende vulkaanuitbarsting, dat gebeurde op El Hierro voor het laatst in 1793. Indien het toch zover zou komen, is het niet nodig om alle tienduizend inwoners te evacueren, zei veiligheidschef Juan Manuel Santana aan de krant El Pais.

Veiligheidsverantwoordelijken zouden aan verschillende evacuatiescenario's aan het werken zijn. Ook worden overal op het eiland vergaderingen gehouden om de inwoners te informeren wat er moet gebeuren in geval van een uitbarsting.

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Op vrijdag 30 september 2011 10:21 schreef Scrummie het volgende:
Is er nou wel of geen risico tot uitbarsting? Ik lees zoveel tegenstrijdige dingen :S. Dan worden mensen geevacueerd, en even later worden ze weer terug gestuurd en is er geen beving meer waargenomen :S.

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Op vrijdag 30 september 2011 10:51 schreef stan12 het volgende:
http://www.avcan.org/

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Op vrijdag 30 september 2011 11:08 schreef stan12 het volgende:

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Nee, helaas niet! Lees hier al jaren mee maar heb me net maar eens aangemeld. Vind vulkanen ook zeer vet en vooral na mijn vakantie in IJsland.

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Op vrijdag 30 september 2011 11:57 schreef Takkembah het volgende:

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Huh, je kunt toch ook Engels klikken op de site?

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Hierro Volcano - John Seach

El Hierro, Canary Islands, Spain
27.73 N, 18.03 W
summit elevation 1500 m
shield volcano

El Hierro volcano is the westernmost, youngest and smallest of the Canary Islands. In the 2nd century A.D., Ptolemy considered it the western-most position of the world.

El Hierro Island covers an area of 278 sq km, and contains three well-defined ridges, arranged at approximately 120 degrees. According to the hotspot model of volcano formation, the current location of the Canary islands hotspot is under Hierro Island.

El Hierro volcano is still in its juvenile stage of shield growth, and has been modified by gravitational spreading which caused gigantic landslides. There are three volcanic structures on El Hierro Island - elongated topographic ridge (the Southern Ridge) and two semi-circular volcanic cones (Tinor volcano, El Golfo volcano).

Tinor Landslide was the earliest and directed to the northwest of Hierro Island.

El Julan produced a 15 km wide embayment in the southwest of the island. The landslide was approximately 60–120 cubic km in volume, and covered 1600 sq km of ocean floor.

Las Playas Landslide directed SE and had a volume of 25-35 cubic km.

El Golfo, Debris Avalanche
El Golfo is a major debris avalanche on the northern flank of Hierro Island, dated about 13,000 years ago. It has a width of 15 km and a scarp height of 1000 m. The landslide deposited 150-180 cubic km of debris on the seafloor down to a depth of 3000 m.

2011 Unrest
An earthquake swarm occurred at El Hierro volcano in July 2011 with 720 earthquakes measured in a week. The earthquakes were measured between magnitude 1-3, and most were at a depth of 5-15 km. The swarm occurred at El Golfo in the northwest of the island at the location of a landslide that created a 100 metre high tsunami about 50,000 years ago. The earthquakes were continuing at the end of September and some evacuations were ordered for people living near the volcano.

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Op maandag 3 oktober 2011 11:19 schreef Jumparound het volgende:

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En waarop baseren ze dat dan?

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2011-10-03 10:54:15.31hr 32min ago 27.64 N 18.07 W 17 2.8 CANARY ISLANDS, SPAIN REGION

2011-10-03 10:27:49.61hr 58min ago 27.63 N 18.07 W 14 2.7 CANARY ISLANDS, SPAIN REGION

2011-10-03 10:14:43.42hr 12min ago 27.63 N 18.08 W 15 3.4 CANARY ISLANDS, SPAIN REGION

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Magma on the move in El Hierro, Canary Islands

This is happening faster then I expected. But it seems that magma is now on the move upwards in El Hierro volcano in Canary Islands. This is evident by the earthquake patterns that are emerging from the volcano. Given the earthquake locations, most likely place for a eruption to take place is out on the ocean based on that. But sometimes magma can find different pathways up the surface without a lot of warning.



Latest earthquake map from Instituto Geográfico Nacional that shows clearly the earthquake pattern since the dike intrusion did start in El Hierro. Copyright of this picture belongs to Instituto Geográfico Nacional.

At the moment it is impossible to know when and where a eruption might start. It depends on many factors. But it is now clear that magma is on the move upwards. So far the magma seems to be around 10 km up in the earth crust under El Hierro. So it is clear that the magma is on the way up and most likely preparing for a eruption.

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35mm deformation at El Hierro
The Instituto Geografico Nacional (IGN) has reported surface deformations exceeding 35mm on the Spanish island of El Hierro, where residents have been alert for a possible volcanic eruption. The number of earthquakes recorded since July 17 on the smallest of The Canary Islands exceeded 9250 on Tuesday morning. IGN confirmed on Monday that 1172 earthquakes were recorded last week, the majority of which were located in the sea to the SW of the 280-sqkm island. 52 of the earthquakes were felt by the local population, estimated to be approximately 10,000. A further 10 earthquakes, exceeding 3.0 magnitude on the Richter Scale, were felt during Monday and early on Tuesday. Hierro, a shield volcano, has had a single historic eruption from the Volcan de Lomo Negro vent in 1793. The eruption lasted approximately one month and produced lava flows. The recent surge in the number and intensity of earthquakes prompted officials from the IGN and The Canary Islands Government to raise the alert level for the Hierro volcano to ‘Yellow’ late last month.

Seismologists say the majority of the earthquake activity has shifted from El Golfo in the island’s northwest to beneath the Las Calmas Sea in the south. However, magma is now on the move upwards while the depth of earthquakes has become increasingly shallow in recent days with most being recorded at a depth of 10 to 14 kilometres. Movement of magma towards the surface signifies that a volcanic eruption is likely to happen, but the timing of such remains unclear. Volcanologist Juan Carlos Carracedo last week suggested that an eruption on El Hierro would “not be a major surprise”. He explained: “It is the youngest of the Canary Islands. There is a ball of magma which is rising to the surface and it is stationed at the limit of the earth’s crust. At the moment we do not know if that ball of magna will break the crust and cause an eruption.” IGN Director, María José Blanco said that any eruption on El Hierro would most likely have a “low explosion value”.

A dramatic rise in recorded earthquakes on El Hierro last Tuesday prompted officials to evacuate some local residents, shut El Hierro’s main tunnel, and close local schools. The Spanish Civil Guard (Guardia Civil) advised almost 50 residents of the municipality of La Frontera to leave their homes because of landslide fears. Two units of the Spanish military’s emergency intervention unit (EMU) were also placed on standby to depart the nearby island of Tenerife to assist in the possible evacuation of hundreds of other El Hierro residents. Meanwhile, the island’s main tunnel (Tunel del Golfo), which links Frontera to Valverde, was shut forcing motorists to travel across the 280-sq-km island via a mountain road. The Cabildo de El Hierro also ordered the closure of schools on Wednesday.

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El Hierro scientist:'More worried about earthquakes'
The Scientist in charge of the team studying the seismic activity on the Canary Island of El Hierro, Nemesio Pérez, has told the press how is is more concerned about earthquakes on the tiny island than he is of any Volcano eruption "Usually in the Canaries, they have not been that explosive, just trickles of lava. There are victims when there are earthquakes, which is why I am more concerned about the earthquakes rather than the eventual eruption."

Perez, who is the scientific coordinator of the Canaries Institute of Volcanology (Involcan) continued : "Spain has a seismic alert system comparable to that of a third-world country," he says. "Predicting volcanic activity has three components: tremors, gas emissions and deformations. But in Spain, attention is only paid to the first stage."

He told reporters how any volcanic eruption would not be rare, but the uncertainty stems from the fact that in El Hierro there isn't just one major volcano but around 500 vents on the island. As such, no one can be sure where the lava will flow if there does end up being an eruption.

The problem that this causes is that it is impossible to monitor and cordon off each and evert vent, but each one could still produce potentially fatal toxic fumes.

The Island residents have actually felt around 60 of the 9'000 recorded earthquakes over the past two months, however the frequency and strength has increased over the past two weeks.

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Vulkaanuitbarsting Tenerife helpt aardverschuivingen te begrijpen

AMSTERDAM - De ontdekking van een grote vulkaanuitbarsting op Tenerife van 733.000 jaar geleden werpt nieuw licht op aardverschuivingen. Zo is men in de toekomst mogelijk beter voorbereid op de gevolgen van dit soort grote catastrofes.

Vulkanologen van de Universiteit van Leicester ontdekten op het Canarische eiland Tenerife een aardverschuiving ten gevolge van een grote vulkaanuitbarsting waarbij een deel van de zijkant van de vulkaan de zee in verdween.

Ze publiceerden hun bevindingen in de oktober-editie van het tijdschrift Geology.

Bijzonder

Het is bijzonder dat niet vrijwel de hele aardverschuiving door de uitbarsting de zee in verdwenen is. "Het is een van de best bewaarde en toegankelijke voorbeelden van zo’n ontzagwekkend fenomeen, omdat het puin van zulke aardverschuivingen zich meestal over de oceaanbodem verspreid en daardoor ontoegankelijk voor verdere studie", verklaart Dr. Branney, een van de onderzoekers.

Het achtergebleven puin en gruis op Tenerife bevat onder andere blokken van snel afgekoeld stollingsgesteente. Radioactieve mineralen in de gestolde lava maakten het voor de onderzoekers makkelijk om zeer precies de datum van de uitbarsting te bepalen.

Klimaatverandering

Klimaatverandering wordt vaak aangewezen als reden voor aardverschuivingen op eilanden in de oceaan. Dat was nu niet het geval. Een groeiende koepel van hete lava duwde van binnenuit de zijkant van de vulkaan naar buiten toe.

Zulke gebeurtenissen zijn niet ongewoon, maar komen zeer onregelmatig voor. Ze begrijpen is daarom van belang omdat de effecten duizenden kilometers verderop grote problemen kunnen veroorzaken.

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2011-10-06 12:27:35.131min ago 27.67 N 18.04 W 13 3.1 CANARY ISLANDS, SPAIN REGION
2011-10-06 10:47:31.92hr 11min ago 27.69 N 18.04 W 14 2.8 CANARY ISLANDS, SPAIN REGION
2011-10-06 10:38:24.52hr 21min ago 27.67 N 18.04 W 12 2.5 CANARY ISLANDS, SPAIN REGION
2011-10-06 10:35:53.02hr 23min ago 27.66 N 18.02 W 14 2.7 CANARY ISLANDS, SPAIN REGION
2011-10-06 10:30:10.72hr 29min ago 27.68 N 18.03 W 16 2.5 CANARY ISLANDS, SPAIN REGION
2011-10-06 10:28:05.02hr 31min ago 27.67 N 18.03 W 12 2.6 CANARY ISLANDS, SPAIN REGION
2011-10-06 10:24:34.72hr 34min ago 27.69 N 18.03 W 16 2.5 CANARY ISLANDS, SPAIN REGION
2011-10-06 10:21:02.02hr 38min ago 27.69 N 18.02 W 16 2.5 CANARY ISLANDS, SPAIN REGION
2011-10-06 10:16:11.02hr 43min ago 27.68 N 18.03 W 16 2.6 CANARY ISLANDS, SPAIN REGION
2011-10-06 06:34:04.36hr 25min ago 27.69 N 18.05 W 13 2.6 CANARY ISLANDS, SPAIN REGION
2011-10-06 05:43:12.37hr 16min ago 27.69 N 18.04 W 12 2.8 CANARY ISLANDS, SPAIN REGION
2011-10-06 05:03:17.07hr 56min ago 27.67 N 18.04 W 12 3.2 CANARY ISLANDS, SPAIN REGION

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Op donderdag 6 oktober 2011 15:45 schreef bwt het volgende:
is ook erg goed te zien op de seismogr. data van mijn vorige post.

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Earthquake activity on El Hierro intensifies
The Instituto Geografico Nacional (IGN) has reported an increase in the intensity of earthquakes recorded on El Hierro, the smallest of The Canary Islands, during the last 24 to 36 hours. The number of earthquakes recorded since July 17 , 2011 on El Hierros has now reached 10,000, figures from the IGN confirm.

The IGN also confirmed surface deformations exceeding 35mm on the 280-sqkm island, where residents have been put on alert for a possible volcanic eruption. However, seismologists have moved to reassure the local population that a volcanic eruption is not imminent.

The agency confirmed on Friday that 890 earthquakes, most of them located in the sea to the SW of the island, have been recorded in the 7 days since 01 October, 2011. During this period, 76 earthquakes were felt by the island’s estimated 10,000 residents.

Since Friday morning, there have been 14 earthquakes exceeding 3.0 on the Richter Scale with epicentres both North and South of the NW Ridge and depths between 10 and 15 km have been recorded. The strongest of the tremors measured 3.8 magnitude on the Richter Scale. A total of 17 earthquakes were felt by the local population.

Hierro, a shield volcano, has had a single historic eruption from the Volcan de Lomo Negro vent in 1793. The eruption lasted approximately one month and produced lava flows.

The recent surge in the number and intensity of earthquakes prompted officials from the IGN and The Canary Islands Government to raise the alert level for the Hierro volcano to ‘Yellow’ late last month. The alert remained in place on Saturday.

Seismologists say the majority of the earthquake activity has shifted from El Golfo in the island’s northwest to beneath the Las Calmas Sea in the south.

However, magma is now on the move upwards while the depth of earthquakes has become increasingly shallow in recent days with most being recorded at a depth of 9 to 14 kilometres. Movement of magma towards the surface signifies that a volcanic eruption is likely to happen, but the timing of such remains unclear.

Volcanologist Juan Carlos Carracedo last week suggested that an eruption on El Hierro would “not be a major surprise”. He explained: “It is the youngest of the Canary Islands. There is a ball of magma which is rising to the surface and it is stationed at the limit of the earth’s crust. At the moment we do not know if that ball of magna will break the crust and cause an eruption.”

IGN Director, María José Blanco said that any eruption on El Hierro would most likely have a “low explosion value”.

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Strongest quake so far hits El Hierro
Update 08/10 – 22:15 UTC : Tonight at 20:34 UTC, the strongest earthquake so far has occurred below El Hierro at a depth of 10 km (data EMSC). The earthquake had a magnitude of 4.3!
IGN data

2011/10/08 20:34:48.28 depth 12.5 km Magnitude 4.30

Following IGN , the epicenter was approx. 600 meter out of the coast.
Following IGN the earthquake was felt as an intensity MMI III earthquake (weak shaking).
Earthquake-Report.com is convinced that the return of the evacuated people to their villages might be postponed for some time after this moderate volcanic earthquake. The evacuation took place after the authorities had to act because of landslide risk which could have been triggered by the quakes.
At the other hand the number of earthquakes of M 2 or higher has decreased substantially today as their were only 4 since the last 20 hours.

Update 07/10 – 23:30 UTC : The 2 strongest earthquakes today had a magnitude of 3.7 and 3.8 at a hypocenter depth in between 12 and 16 km. They occurred at 11:27 and 22:29 UTC. Normally this kind of earthquakes are felt by humans.

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During the night 17 earthquakes, 9 of them less than 10 km deep. to prof. 2, 3, 2, 2, 1, 2, 2, 1 and 1

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The volcanologists warned a possible volcanic tremor early this morning from El Hierro

Canary Island volcanological Association, through its website on Facebook (Current Volcanic Canary Avcan), has publicly called the National Geographic Institute (about 9:30 hours) "to confirm or disprove the existence of the signal and make an interpretation of the current situation. "Avcan the social network said: "This morning, from 4:18 pm. Or so there has been registering at the station of El Hierro CHIE what could be a sign of volcanic tremor."

The association notes that those tremors are typical "of active volcanoes and indicate magma movement," while begging the public to remain "very calm and avoid unnecessary alarm", since "if it is confirmed that the signal we see at the station CHIE of El Hierro is a tremor, would be within the predictability in the process that is lived on the island since last July. "

Avcan current situation recalls the yellow light to monitor the seismic crisis of El Hierro, insists on asking "a lot of courage and peace" and stressed that "people should be aware of submissions from civil protection authorities."

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Submarine eruption occuring at El hierro
Seismic monitoring services have been a small submarine eruption at 1,200 meters deep at sea seven miles from El Hierro.

The phenomenon is ongoing and has occurred at 10.43 (local time) in the sea calms and has been a sudden change in the seismic process, as it has paralyzed for weeks tremors felt in the Canary Islands, as reported by experts to Canary Autonomic Radio.

As reported Canarias7, four ships have been alert to the maritime authorities of the existence of volcanic activity south of La Restinga and about 500 meters deep.

This same media reports that emergency services have issued instructions to all diving clubs of El Hierro to suspend any dive on its shores, which are among the most appreciated by fans of the sport because of its biological richness funds.
The first since 1971

If confirmed, this eruption was the first of which is recorded in Spain since 1971, when it emerged Teneguía volcano on the island of La Palma, Canary Islands too.

The eruption may have started this morning on the southern coast of the island, the least populated.

From 11.00 hours (local time) is met in Valverde, the capital of El Hierro, the monitoring group for this type of crisis set by the Civil Protection Special Plan and Emergency Response for Volcanic Risk (Pevolca) de Canarias.

Following that meeting, the authorities are expected to offer a press conference to report on the details of what happened and security measures will be taken on the island.
Earthquake of 4.3

El Hierro has suffered since mid-July around 9600 earthquakes caused by magma activity in the basement of the island.

Just today the eruption takes place two days after he recorded an earthquake of 4.3 magnitude on the Richter scale. This figure made him the most intense earthquake recorded by the National Geographic Institute (IGN) since last July 17, when earthquakes began on the island.

The earthquake, which was felt throughout the island, caused no injury, but caused landslides on the outer slopes of the tunnels and on the road Roquille linking Tacorón to La Restinga, in the southern municipality of El Pinar.

In the first week of October, the IGN has located 890 earthquakes, most of them situated in the sea, southwest of the island.
Yellow alert

The situation remains yellow alert, so that the sequence of earthquakes senses falls within the normal range.

From the July 17 IGN has registered and located nearly 10,000 earthquakes, with epicenters both north and south of the NW ridge and depths between 10 and 15 km. The number of events felt by the population is 133, with intensities II, III and IV in the scale EMS 98.

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Op maandag 10 oktober 2011 12:40 schreef quirina het volgende:
http://www.hollandsenieuw(...)-op-el-hierro_33363/

Ik weet niet of dit al gepost is maar dit is ook wel een goed blog om bij te houden.

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IGN has confirmed early this morning for a small release of fluids and volcanic gases that do not pose such risk to the population

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Aanwijzingen voor vulkaanuitbarsting Canarisch Eiland

In de omgeving van het Canarisch Eiland El Hierro is mogelijk een vulkaanuitbarsting begonnen. Het Spaanse persagentschap EFE meldde vandaag onder aanhaling van experten dat volgens de jongste computergegevens op een diepte van 2.000 meter onder de zeebodem ten zuiden van El Hierro een eruptie aan de gang is. Volgens de Canarische radio zijn alle duikclubs op het eiland verwittigd hun activiteiten in het water te staken.

Op het kleinste van de Canarische Eilanden zijn sinds juli ongeveer 9.600 zwakke aardschokken geregistreerd. Ze gelden als een voorteken op een vulkaanuitbarsting. De zwaarste aardbeving deed zich zaterdagavond voor met een kracht van 4,3 op de schaal van Richter. Sinds weken heerst er op het eiland de alarmfase geel, waardoor de zowat 10.000 bewoners op een mogelijke evacuatie moeten voorbereid zijn. (dpa/dea)

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The submarine volcanic eruption of El Hierro magma and gases released into the ocean
Scientists detect the phenomenon to three miles south of the island and 900 meters deep .- The population has not been affected but the marine fauna

Forty years after the Teneguía, La Palma, Canary Islands relives a volcanic eruption. Yesterday at 6.20 (GMT), seismographs to the National Geographic Institute (IGN) has deployed around the island of El Hierro began to show an anomalous signal. Since the July 19 seismic crisis began, the curves marked as small jumps for each of the more than 9977 earthquakes. After a day of uncertainty, rumors and denials, Carmen Lopez, head of the volcanology of IGN, just after 22.30 confirmed that there had been a submarine eruption and said he was dating magmatic material. According to Lopez, the seismicity suggests that occurred three miles south of the island and 900 meters deep. Experts do not rule out that another eruption could occur closer to the coast but consider the low probability.

The scientists listed various circumstances that test the eruption: detection by the seismographs of the "volcanic tremor", the slowdown of earthquakes, the decrease in magma pressure, thereby reducing the swelling of the island, and the issuance of gases, which has affected marine life, according to pictures broadcast but not discussed by the authorities. They can see dead fish floating in the water. There is no visible evidence, as the huge column of water prevents gas to surface water to the surface. On this island in 1793 there was a seismic crisis similar to that experienced in recent months, but no record that ended in an eruption.

The president of the Cabildo Insular de El Hierro, Alpidio Armas, present at the meeting of politicians, scientists and technicians who made ​​the announcement, said that this is a joy because just with an uncertainty that has lasted months. Armas also said that in the absence of an opinion of the technicians is expected to reopen today The Roquille tunnel, which links the capital, Valverde, airport and port of the stake with the municipality of La Frontera, a closure that according to some businessmen were financially strangling the island. This technical report will also decide whether the two dozen displaced families can return to their homes. The alert level on the island will continue for the time in yellow.

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Dead Fish, eruption vent at 600m depth
Update 11/10 – 09:24 UTC : Ay 9 PM UTC yesterday, authorities have finally confirmed that an eruption took place on the ocean floor 5 km from Restinga, the southernmost location on El Hierro. IGN (Spanish seismological agency) has set the eruption depth at 600 meters. The alert level remains at yellow and authorities are asking the population to remain calm. The confirmation came after that scientists from IGN and CSIC (Consejo Superior de Investigaciones Científicas) have been circling the presumable spot of the eruption with helicopters. An important number of dead fish where the convincing sign that an eruption took place. Until then it was presumed that an eruption took place, but only based on indirect instrument readings (harmonic tremors, decrease of deformation, etc.).
Carmen Lopez from IGN, said to the press that the next 24 hours will indicate whether the eruption vent widens in if it does, in which direction (towards the island or towards the south).

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Op dinsdag 11 oktober 2011 11:54 schreef Californian het volgende:
Volgende week zit ik op Gran Canaria. Is daar ook wat te voelen?

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At 04:18 UTC on 10 October, 2011 a eruption did start somewhere close to the El Hierro volcano Island (but inside El Hierro volcano system). So far nothing has been seen to this eruption, so location is uncertain at the moment. At the moment this eruption has only been confirmed by harmonic tremors seen on seismometers on El Hierro island.

From what I can tell, based on the harmonic tremor plots. It seems that the eruption has been growing in size since it started well over 12 hours ago. This suggests that the eruption is growing in size. That also brings up the issue that new fissures might open, both into deeper ocean and on shallower depth and even on land without any warning at all.

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Op dinsdag 11 oktober 2011 12:39 schreef Five_Horizons het volgende:

[..]

Ik zie je plaatjes ook niet, idd...

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Op dinsdag 11 oktober 2011 12:57 schreef bwt het volgende:
URL van plaatje in apart venster/tab openen en een keer F5

twitter:

teideano twitterde op dinsdag 11-10-2011 om 13:40:34 @eruptionsblog some reports of felt tremor by some....ok, really prelimianr and needs confirmation, but if felt, then we have a problem. reageer retweet

twitter:

canariesnews twitterde op dinsdag 11-10-2011 om 16:01:17 New earthquake felt in the La Restinga area of El Hierro as residents are evacuated to sports venue 'as a precaution'. http://t.co/9Ph2lPoL reageer retweet

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Op dinsdag 11 oktober 2011 17:33 schreef Keiichi het volgende:
Ik heb het ook maar even naar de FP gesubmitted. Vind het nu wel belangrijk genoeg ervoor

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Op dinsdag 11 oktober 2011 18:21 schreef pfaf het volgende:
Spannend zeg. In negatieve zin.
Vreemd dat er in de media niets over gerept wordt. Of mis ik dat?

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Op dinsdag 11 oktober 2011 18:25 schreef Jumparound het volgende:

[..]

het is niet spannend of boeiend :-)
Ook heeft de vulkaan geen vermoord zusje of hoge schulden...

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Op dinsdag 11 oktober 2011 20:46 schreef Keiichi het volgende:
Nu moet het toch wel op FP komen?

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Op woensdag 12 oktober 2011 00:26 schreef Jumparound het volgende:

[..]

het was geen sneer naar jou of fok hoor, maar naar de msm in het algemeen. Ik vind dit een super topic om te volgen!

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Op woensdag 12 oktober 2011 02:21 schreef thesiren.nl het volgende:

Ik kan niet zonder mijn dagelijkse frutsel update. Vaak zit ik in onstuimig nou gebeurd er nog wat, als ik dan je post zie bij laatste post dan weet ik, Hé nieuwe ontwikkelingen.

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Op woensdag 12 oktober 2011 07:38 schreef Keiichi het volgende:
Vulkanische activiteit op Canarisch eiland



Maar mijn submit staat nog in wachtrij

Bron: Novum/AP

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Hundreds evacuated of Restinga (Google Translate)
Already there has been completed the evacuation of 547 inhabitants of The Restinga

Only half a hundred of persons needs an emergency housing

It is believed that the eruption will be more superficial and with ' major explosivity '

The people(village) is the populated point nearest to the submarine eruption of yesterday

Maxim is alert in the south of The Iron. The inhabitants of The Restinga have been evacuated to Valverde and other points of the island more removed from the coast without any incident, after having be Raised up to red level the semaphore of volcanic alert In this locality for the possibility that there takes place(is produced) an eruption more superficial than that of yesterday.

The general manager of Security of the Government of Canaries, Juan Manuel Santana, has made clear that this measure takes with Preventive character, Before the seismic signs that indicate that it is probable that a new eruption takes place(is produced) In waters nearer to the coast and less deep That on the one that was registered yesterday, Monday.

" An eruption in more shallow waters might produce major risks, because it(he,she) would have major explosivity ", Santana has indicated. The rest of the island they are in yellow alert.

In a press conference offered in Valverde, the capital of the island, Santana has preferred not speaking about "evacuation", but of " Preventive movement ", Because the situation can change with the course(year) of the hours and still(yet) there is no certainty from which the neighbors of The Restinga have to happen(pass) the night out of his(her,your) houses.

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El Hierro tsunami chance
The Canary Islands Directorate for Civil Protection and Emergency Response yesterday raised the state of alert for seismic and volcanic activity on the Island of El Hierro to red.

The CEO of the agency explained that the increased state of alert only applied to the municipality of La Restinga and the rest of the island remains of yellow alert.

La Restinga (547 inhabitants) is a Town on the southernmost coast of the island, and is closest to the underwater eruption which occurred yesterday, 5 kilometers from the coast and at an estimated depth of 1000mts.

The CEO also stressed that this was purely a precautionary measure and that there was no immediate threat of danger, however there is a strong likelihood of a further eruption over the next few days.

Experts from the National Geological Survey and the Higher Council for Scientific Research (CSIC) moved to the island have not ruled out the possibility that any such eruption, together with increased levels of magma rising to the surface could result in a new Volcano being created on the island.

The volcanic activity has attracted much interest from around the world - especially in the USA. It has long been speculated that any volcanic eruption of the Caldera de Taburiente Volcano on the neighbouring island of La Palma may cause a Tsunami of up to 300mts that would cross the Atlantic in a matter of hours. Geologists believe that this is exactly what happened when the El Hierro Volcano broke apart and fell into the Ocean thousands of years ago, creating the 'Val del Golfo' crescents shaped bay, and creating a Tsunami that was largely responsible for the creation of the Florida Everglades.

Chatter on the various social networks and forums critcises the United States Geological Survey (USGS) for their lack of communication surrounding the situation in the Canaries. Sources claim that this is so not to panic the public unnecessarily.

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13/10/2011 @ 09:01 – A new earthquake has been detected, this time to the north-east of the island. Until now, all the earthquakes have been located to the south coast. It took place at 05:10:36 (local time) and registered 1.7 on the Richter scale.

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El Hierro update 2
The eruption in El Hierro volcano continues today, as it did yesterday. But the strength of the eruption appears to have dropped today from what it was yesterday. But this does not mean that the eruption is over. It just means that the current fissure that is erupting is about to close up, mostly due to the material that it has been ejecting into the ocean floor. That means a new fissure or vents is about to open up somewhere. When and where is impossible to know. But this is the nature of volcanoes that erupt in this manner, but El Hierro is a shield volcano [second link here]. Good examples are Krafla volcano and Vestmannaeyjar Island volcano. Both of those volcanoes are in Iceland.

Today around 14:20 UTC there was a sharp tremor drop in El Hierro. This means that the magma flow dropped in the current eruption fissure. This also means that if the pressure is not enough that fissure is going to stop erupting. Because of this has happened a new fissure or a vent should be expect at any time as I have told before. When and where that might happen is impossible to know, as that outcome depends on where the magma finds its pathways inside the volcano. There might not be any earthquakes before this happens, as the rock is unlikey to be hard enough to make them. Some small earthquakes might happen if the rock layer is hard enough. Today few deep earthquakes have been recorded. This means that new magma is getting into El Hierro volcano from the mantle (where no earthquakes happen). This also means that this eruption might take place for some time now. But it is impossible to know for how long, as there might be a lot of magma flowing up from the mantle it self and up to El Hierro volcano.

Many people have been wondering why this eruption has not been seen. The fact is that depth drops quiet fast around El Hierro Island. Around 4 km out the depth is close to 1.5 to 2 km, it is only close to the island that the depth starts to get shallower. At the moment is is hard to say what happens next in this eruption on El Hierro. But more vents should be expect to open up then have already have.

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Op donderdag 13 oktober 2011 23:50 schreef stan12 het volgende:
Rustiger aan het worden?
http://www.02.ign.es/ign/(...)es=10&Dia=13&tipo=1#

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Op vrijdag 14 oktober 2011 10:37 schreef Tokamak het volgende:
En hij zit dicht (voor nu).
http://www.02.ign.es/ign/(...)Mes=10&Dia=14&tipo=1

Edit: Toch niet, de transponder hapert

Edit 2: Wat me wel opvalt is een zeer laagfrequente trilling, meetbaar bij andere eilanden:

Fuerteventura:
[ afbeelding ]

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