Category: Earthquakes

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Minor earthquakes in Hekla volcano system

During the past 24 to 48 hours there has been some unusual and interesting earthquake activity in south part of Hekla volcano system. I am unsure on what this means, as normally Hekla volcano does not have any earthquakes before an eruption. However, that is not the only type Hekla volcano can and has erupted over the centuries. One of the aspect of Hekla volcano eruptions is that it can and has erupted in fissure eruptions outside the main mountain. This type of eruptions can last from few week and up to almost a year. Based on the limited historical records of such events. This type of events are always basaltic lava events that do not make a lot of volcano ash when they start.


The earthquakes in Hekla volcano during the last 48 hours. Copyright of this picture belongs to Iceland Meteorological Office.

There are clues that Hekla volcano might be about to have an fissure eruption some time in the future. But when and where is impossible to know for sure at current time. How that is going to manifest it self when the time comes is also impossible to know for sure. At current time there is however no eruption starting in Hekla volcano. When it might start is an good guess, with no answer to it.

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New magma injection into El Hierro volcano

Based on the earthquake activity in El Hierro volcano it seems that new magma injection has taken place, or is taking place at current time in El Hierro volcano.

This new magma injection into El Hierro volcano has already been followed by stronger harmonic tremors and more activity on the surface. As should have been expected when this happens. It is impossible to know at the moment how large and how long this new magma injection is going to last. But while it is ongoing, more eruption activity should be expected from El Hierro volcano. So far nothing suggests that new vents are about to open up in El Hierro volcano at the moment.

Other then this renewed activity. Nothing else has been happening in El Hierro volcano. There have been some news reports (in Spanish, use Google Translate to read) about new thermal anomalies in El Hierro volcano. This might just be hydro-thermal activity following dike intrusions at shallow depth.

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New earthquake activity in Upptyppingar tuff mountains

During last week and on 5. January 2012 there where few earthquakes in the Upptyppingar tuff mountains. This mountains are not volcano by definition (yet anyway). But since the year 2007 there has been magma intrusion into that area. This magma intrusion however stopped and has been stopped for several years now. But that might be about to change. As on 5 January 2012 there where few small earthquakes with the depth of 12 km. Last eruption that took place in the Upptyppingar tuff mountain area where about 12.000 years ago, around the end of the last ice age. Considerable deformation has taken place in the crust in Upptyppingar tuff mountain since magma started to build up there. Current earthquake activity in Upptyppingar tuff mountain is not high at the moment however. But it has remained rather constant for the past 7 to 10 weeks at least. But due to lack of SIL stations in the area, it is hard to know how many earthquakes have exactly been taking place there at the moment.

Upptyppingar tuff mountains are part of Kverkfjöll volcano system. This new magma into Upptyppingar tuff mountains suggests that Kverkfjöll volcano might be about to enter an new time of activity. But they have been dormant since the year 1968 at least. But Kverkfjöll volcano have also been seeing some earthquake activity on its own.

It is most likely is the case that we are going to see eruption taking place in Upptyppingar tuff mountain one day. But the wait for it might be long however.

A research papers into the activity in Upptyppingar tuff mountain.

Resarch #1 (pdf file)
Research #2 (pdf file)

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Renewed eruption activity in El Hierro volcano

Since yesterday there has been an renewed eruption activity in El Hierro volcano. Harmonic tremor has not seen big increase however. This suggest that this new eruption so far is small and mot procuring a lot of lava to the surface. Some floating pyroclastic has been spotted on web cameras and by local people when they come up to the surface. This eruption activity appears be intermittent at the moment. Going on and off every few hours to days.


The harmonic tremor from the eruption in El Hierro volcano. Harmonic tremor remains low however, so there is not a lot of energy in this eruption at the moment. Spikes in the tremor chart are most likely explosions taking place in the eruption area. Copyright of this picture belongs to IGN (Instituto Geográfico Nacional).

The eruption appears to have started again following an new dike intrusion from great depth into El Hierro volcano. This was followed by few earthquakes. All of them where small. If more new magma flows into El Hierro volcano this new eruption episode is going to increase in strength and in power. But it is hard to be sure if that is going to happen or not.


Eruption area in El Hierro volcano. This new eruption seems to be closer to the coast line then before. Copyright of this picture belongs to INVOLCAN. Picture is via Eruption blog (Erik Klemetti)

It is impossible to know what happens next in El Hierro volcano. So watching is important thing to do.

Other blogs about this new eruption.

Renewed Activity at El Hierro in the Canary Islands (Wired Science)

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An ML3.5 earthquake west of Lanzarote and Fuerteventura Islands

Today at 17:05 UTC today (05.01.2012) there was an ML3.5 earthquake outside the Lanzarote (Wiki) and Fuerteventura (Wiki) Islands, in the Canary Islands. This earthquake was tectonic in nature, so no it not connected any volcano activity from what I can tell at current time. But I have limited data to base my opinion on. I do not know if this earthquake was felt. But given the distance to next population I find it unlikely to be the case.


The location of the earthquake according to IGN. Copyright of this picture belongs to IGN (Instituto Geográfico Nacional).


The earthquake as it did appear on the nearby seismometer. Copyright of this picture belongs to IGN (Instituto Geográfico Nacional).

According to this image there where two earthquakes that took place. Right after the ML3.5 earthquake an smaller earthquake did take place. But there is no size for it. But I am guessing that it is around ML1.2 in size (at least). No more earthquakes have been detected in this area since this earthquake took place earlier today.

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Eruption starts again then stops again in El Hierro volcano

Few weeks ago the eruption in El Hierro volcano stopped for few hours. Before it did restart at lower levels for few days. Then it stopped again. This type of behavior is not so unexpected as it seems that El Hierro volcano did get some minor magma injection in past few days and around the time the eruption did restart. But this injection of new magma was followed by minor earthquake swarm in El Hierro volcano, with one of the earthquake having the depth of 34 km (automatic depth estimate I think). But this new injections of magma seems to be small compared to the amount of magma that has already been injected into and erupted already in El Hierro volcano.


Harmonic tremor yesterday (03-01-2012) in El Hierro volcano. Copyright of this picture belongs to IGN (Instituto Geográfico Nacional).


Harmonic tremor today (04-01-2012) in El Hierro volcano. Copyright of this picture belongs to IGN (Instituto Geográfico Nacional).

Current level of harmonic tremor in El Hierro volcano suggests an small eruption in the area. But there is now an highly active hydro-thermal area where the eruption started and has been taking place for the past three months. But it is going to take several weeks and up to years for this area to cool down. Then there is also the chance of hydro-thermal activity in the area if there is an dike intrusion into the rock of the El Hierro volcano that has not erupted. If that is the case as might well be. It is going to decades and up to hundreds of years to cool down.

For the moment however the main eruption event in El Hierro volcano is over and it is going to remain like that until new magma is injected into volcano. But that might not happen for hundreds to thousands of years if the current sequence of events that led to current eruption is over. But only time is going to tell us what happens next is El Hierro volcano. As volcanoes are unpredictable in there nature.

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A ML3.4 earthquake 25 east of Grímsey Island (automatic size)

When things gets busy in Iceland, they mean it. At least that is the case now. This also the reason why I do not trust the quiet times in Iceland.

A earthquake with the size of ML3.4 took place 25 km east of Grímsey Island in the TFZ at 21:46 UTC. But that is an non-volcanic zone that bridges the eastern volcanic zone with the North-Atlantic rift zone. This earthquake had an earthquake with the size of ML2.9 taking place before the larger one. That was an pre-earthquake most likely. But it seems that an earthquake swarm is also starting in TFZ as it has done close to Krísuvík volcano on the Reykjanes Ridge. I do not know if this earthquake was felt or not.

I am going to update this blog post if I need to.

Update 1: The location of this earthquake. So far there have not been any aftershocks following the ML3.4 earthquake. Its depth was at 11.5 km. This earthquake does not appear clearly on my geophones due to the distance involved (over 200 km).


The location of the ML3.4 earthquake on TFZ. Copyright of this picture belongs to Iceland Met Office.

Blog post updated at 22:22 UTC.

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A ML3.6 earthquake in Krísuvík volcano (automatic size)

At 21:12 UTC on 3. January 2012 an earthquake with the automatic size of ML3.6 did happen in Krísuvík volcano. I do not yet know if this earthquake was felt in the nearby area. But I assuming that it has done so.

This earthquake did appear clearly on my geophones. Both in north and south Iceland. They can be viewed here. I am going to update this blog post as I know more. But this seems to be an start of earthquake swarm in Krísuvík volcano.

Update 1: It has been confirmed that this earthquake was felt in Reykjavík and nearby area. The automatic depth of this earthquake was 14.2 km according to Iceland Met Office.

Update 2: Earthquake swarm has started in Krísuvík volcano. The largest earthquake in this earthquake swarm after the main earthquake is ML1.1 in size. Larger earthquakes however might happen at any time in this earthquake swarm. But that is at least the experience so far.

Update 3: Here are the traces of the earthquake. Sorry. But for the moment there are no high resolution pictures available as my main earthquake computer is offline until I move back to Denmark. See this blog post here for more details on that.


The location of the ML3.6 to ML3.7 earthquake in Krísuvík volcano. Copyright of this picture belongs to Iceland Met Office.


The ML3.6 earthquake as it did appear on Eyrarbakki geophone. This picture is released under Creative Commons Licence. Please see the CC Licence web page for more detail.


The ML3.6 earthquake as it did appear on the Heklubyggð geophone. This picture is released under Creative Commons Licence. Please see the CC Licence web page for more detail.


The ML3.6 earthquake as it did appear on the Hvammstangi geophone. This picture is released under Creative Commons Licence. Please see the CC Licence web page for more detail.

Blog post updated at 21:38 UTC.
Blog post updated at 21:45 UTC.
Blog post updated at 22:15 UTC.

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Hekla volcano is quiet

I have been seeing some rumors about Hekla volcano might be about to erupt. This is wrong. For the moment Hekla volcano is quiet as it has been since the last eruption in the year 2000. For few years Hekla volcano did erupt for about every 10 years. That might have change already. Nobody is sure on that now. But one thing is clear Hekla volcano is going to erupt one day. But when is always the question.

People have been speculating on the earthquakes west of Hekla volcano. This earthquakes do not belong to Hekla volcano. They are part of activity in the SISZ (South Icelandic Seismic Zone). Earthquakes in this area tectonic in nature, not volcanic. So in worst case, this earthquakes might be sign of new major earthquake preparing to take place some day in the future.

For the moment however. Everything is quiet in Hekla volcano.

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Hydrothermal activity in El Hierro volcano

For the moment the eruption in El Hierro volcano has ended. The current harmonic tremor that is being detected might well be from hydrothermal activity that is currently in the area that erupted. But even if the eruption has ended, the area that erupted is going to be warm for many weeks to come. This is going to create hot springs below the sea level, among other ocean phenomena connected to this type of hydrothermal activity.


Harmonic tremor levels remain close to background levels at El Hierro volcano. Taken today at 16:05 UTC. Copyright of this picture belongs to IGN (Instituto Geográfico Nacional).

As for future activity in El Hierro volcano. It is important to remember that eruption activity might start again on a new fissure. But that would be pre-seeded by earthquake activity. After the eruption activity stopped there has been some earthquake activity. But it is not at that level I would expect before a new eruption where about to start in El Hierro volcano. For the moment however things remain quiet in El Hierro volcano. A relieve to the local people in the area I would think.

Other

I want to remind people of the volcano and earthquake forum. It allows for more discussions on volcanoes, earthquakes and other stuff that might not belong to this blog.