Category: Volcano

Posted on

Earthquake activity in Hekla, Askja volcanoes and TFZ

Before I start. I want to remind people that donations are import to me. Since they help me keeping this blog and my earthquake web page up and running.

Hekla volcano earthquake activity

A minor earthquake activity took place in Hekla volcano yesterday. None of the earthquake was larger then ML1.2. The depth of this earthquake activity was around 8.4 km. This earthquake activity took place outside the main volcano. But was in the connected fissure swarms that extends from Hekla volcano.

130424_0235
Earthquake activity in Hekla volcano system. The earthquakes are the orange dots just south-west of Hekla volcano. Copyright of this image belongs to Icelandic Meteorological Office.

Earthquakes have been taking place in this area for few years now. I do not know what they mean. This might just be a earthquake activity and nothing else. Uncertainty level has been canceled for few weeks now due to lack of any more activity in the main Hekla volcano.

Askja volcano

There has been minor earthquake activity in Askja volcano this past weeks. All of the earthquakes have been smaller then magnitude 1.5. Depth of this earthquakes is around 18 to 22 km. Suggesting that current earthquake activity has its source in magma movements rather then tectonic earthquakes.

130424_1440
Earthquakes in Askja volcano. Askja volcano is the volcano north-east of Vatnajökull glacier. Copyright of this image belongs to Icelandic Meteorological Office.

Tjörnes Fracture Zone

Activity in Tjörnes Fracture Zone has slowed down since 2. April when a large earthquake swarm started in it. But earthquake activity remains as is. Even if the earthquakes are smaller and fewer. This means the earthquake activity has been continuous for the past three weeks.

130424_1650
Earthquake activity in Tjörnes Fracture Zone. It remains in two areas as of now. New activity has also been taking place. Copyright of this image belongs to Icelandic Meteorological Office.

It is difficult to know for sure what happens next in TFZ. But tension in it remains as before and so does the risk for larger earthquake in this area. For the moment however, it remains rather quiet. When that might change is impossible to know for sure.

Blog post updated at 18:16 UTC on 24.04.2013.

Posted on

Earthquake swarm north of Kolbeinsey island

Around 11:00 UTC a earthquake swarm started just north of Kolbeinsey island. This earthquake swarm looks rather powerful. But due to distance from land only the largest earthquakes are appearing on the SIL network and on my geophone at Böðvarshólar. I am estimating the largest earthquakes having the magnitude of 4.0+. But that has not been confirmed yet. Last known eruption in Kolbeinsey island volcano took place in the year 1755. A dike intrusion or a volcano eruption took place north (100 km) of current location back in the year 1999. Last eruption before the eruption in the year 1755 took place around the year 1372.

130413_1745
The earthquake activity in Kolbeinsey island. It is marked by the green stars on this map. Copyright of this image belongs to Icelandic Meteorological Office.

bhrz.svd.13.04.2013.17.55.utc
The earthquake activity as it has been appearing on my geophone at Böðvarshólar. This image is under Creative Commons Licence. See CC licence page for more details.

No signs of eruption have appeared so far. If they do. They are going to appear on the SIL network. I am not sure if my geophone is going to pick them up due to the distance (around 300 km). There is a chance of more earthquake activity to take place in this area in the next few hours to days. I do not know if this activity is connected to what has been taking place in other parts of Tjörnes Fracture Zone. The smaller earthquakes that are taking place in Kolbeinsey island are not being detected by the SIL network or by my geophone.

It is possible to view the earthquake activity here, on my webicorder web page.

Blog post updated at 19:35 UTC on 13.04.2013.

Posted on

Less earthquake activity in Tjörnes Fracture Zone

Yesterday (09.April 2013) there has been less activity in Tjörnes Fracture Zone. The largest earthquakes yesterday did have the magnitude 4.0 and 3.3. A smaller earthquake with the magnitude 3.1 also took place. Many other smaller earthquakes also took place as is normal for this type of earthquake swarm. There are no signs of any volcano activity in the area during this earthquake activity.

130409_2345
Earthquake activity in Tjörnes Fracture Zone during the past 48 hours. Copyright of this image belongs to Icelandic Meteorological Office.

This earthquake swarm does not appear to be over. Even if it has slowed down from its peak one week ago following the magnitude 5.5 earthquake. This type of slowdown are common in this type of earthquake swarms. In many cases the activity stops altogether and starts again after some time. I now believe that current earthquake swarm is connected (not sure how yet) to the earthquake swarm that took place in TFZ in October 2012 and started view few smaller earthquakes and had one magnitude 5.6 earthquake. For now however the earthquake activity is dropping. But it is impossible to know for sure what happens next in TFZ area.

Posted on

Update on the TFZ earthquake swarm at 01:01 UTC

This is a short update on the earthquake swarm in TFZ. This is going to be a long earthquake swarm from the looks of it (currently).

The earthquake swarm in TFZ continues as it has been doing for the past six days now. The strongest earthquakes for the past 24 hours have had the magnitude 3.5, 3.6 and now 3.3 (automatic magnitude). This is a extremely complex earthquake swarm. Over a period of 48 hours there have been around 368 earthquakes. That is a drop in activity, but in the first few hours after the magnitude 5.5 earthquake in TFZ there where recorded over 500 earthquakes.

130406_0015
Earthquake activity in TFZ for the past 48 hours. Copyright of this image belongs to Icelandic Meteorological Office.

130406_0015_trace
The trace plot that shows the earthquake activity for the past 48 hours in TFZ. Copyright of this image belongs to Icelandic Meteorological Office.

This earthquake swarm is complex due to three factors. There is a both slip fault and normal fault taking place there. There also appears to be a volcano in the area. But it not properly understood and is extremely poorly studied. It is unclear at present time if this volcano is connected to this earthquakes swarms at present time. Since so little is known about it. It is also not known if the current earthquake swarm is going to start something in the volcano. The second volcano that is in this area last erupted in the year 1868 following an earthquake swarm in this area. Why that did happen is also not known. But it has a Global Volcanism profile here. The volcano that is closer to Grímsey Island is currently unnamed. There is also almost no studies or documentation on it. But from the little I did find

Please note that the earthquake swarm information is always changing so this information here do get outdated fast. This mostly applies the maps and number of earthquakes.

Scientific data on Tjörnes Fracture Zone

As I did say here above. The Tjörnes Fracture Zone is complex and that is making this earthquake swarm extremely complex as it is taking place.

img94
The rift fault lines in TFZ. This is the simple version. It is from a science study that can be found here. Copyright of this image belongs to Icelandic Meteorological Office/Hjorleifur Sveinbjornsson.

1-s2.0-S0264370706000597-gr2
More complex nature of the fault systems in TFZ. Copyright of this image belongs to Agust Gudmundsson. From study Infrastructure and evolution of ocean-ridge discontinuities in Iceland.

1-s2.0-S0040195107003794-gr1
More complex image showing the fault lines in TFZ. Copyright Ragnar Stefansson, Gunnar B. Gudmundsson, Pall Halldorsson. From the study Tjörnes fracture zone. New and old seismic evidences for the link between the North Iceland rift zone and the Mid-Atlantic ridge.

1-s2.0-S0025322701001724-gr2
The most detailed picture that I was able to find of Tjörnes Fracture Zone and the ocean floor. Copyright of this image belongs to many people. Please see the list of copyright holders in the following link. From the study First observations of high-temperature submarine hydrothermal vents and massive anhydrite deposits off the north coast of Iceland.

It is clearly worth watching this earthquake activity. Since it might have interesting effects on the volcano where this earthquake activity is taking place. Even on the second volcano just north of Þeystareykjabunga volcano.

Posted on

Minor dike intrusion in Bárðarbunga volcano

Today (05.04.2013) a minor earthquake swarm took place in Bárðarbunga volcano. The depth of this earthquakes was around 18 – 26 km. Meaning this is magma, rather then tectonic creating this earthquakes. None of this earthquakes had magnitude above 1.0.

130405_2140
Earthquakes in Bárðarbunga volcano. They are the orange dots. Copyright of this image belongs to Icelandic Meteorological Office.

Dike intrusions happens sometimes in Bárðarbunga volcano without it meaning there is a eruption going to take place soon it. This appears to be one of those cases.

Posted on

Magnitude 3.6 earthquake in Hamarinn volcano

Last night (05.04.2013) at 01:50 UTC a magnitude 3.6 earthquake took place in Hamarinn volcano (no GVP profile yet!). This earthquake had the depth of 2.1 km. This seems to be a dike intrusion taking place in Hamarinn volcano. No clear signs of harmonic tremor have been detected based on tremor data from Icelandic Meteorological Office.

130405_2140
The Hamarinn volcano is where the green star is. But that is the location of the magnitude 3.6 earthquake that took place last night. Copyright of this image belongs to Icelandic Meteorological Office.

skr.svd.05.04.2013.22.12.utc
Harmonic tremor plot do not show any harmonic tremor pulse. The signal on this harmonic tremor plot is the earthquake swarm in TFZ for most parts. Copyright of this image belongs to Icelandic Meteorological Office.

This earthquake activity is due to minor dike intrusion. Rather then something else. It is not clear if this activity is just normal activity for Hamarinn volcano or signal about something else is about take place. But as before. Hamarinn volcano remains mostly quiet for the moment.

Posted on

Deep earthquakes in Askja and Kverkfjöll volcanoes

This is a update for both Askja and Kverkfjöll volcanoes. Since they both had deep earthquakes today. None of this earthquakes where larger then magnitude 1.0. There depth was around 22 to 24 km inside the volcanoes them self.

130331_1700
Earthquakes in Kverkfjöll and Askja volcanoes. There depth was around 22 to 25 km. Copyright of this image belongs to Icelandic Meteorological Office.

GVP Kverkfjöll volcano profile. GVP Askja volcano profile.

It is impossible to know for sure what this means in terms of future activity. But this are both active volcanoes and should be treated as such.

Posted on

Magnitude 4.4 earthquake north of Kolbeinsey Island

Today at 17:32 UTC there was a magnitude 4.4 earthquake north of Kolbeinsey Island. I do not know if this earthquake was tectonic or volcanic in nature. I do know that there where several aftershocks following this earthquake. Since I did register them on my geophone in north Iceland. The geophone web site can be viewed here. More information about the earthquake can be found here, on EMSC web page.

310421.regional.svd.29.03.2013.m4.4
Regional view of the area where the earthquake took place. Copyright of this image belongs to EMSC.

Icelandic Meteorological Office did also detected many of this earthquakes that took place there. But detection from this location is difficult due to distance from the SIL network.

130329_2050
The earthquake swarm location according to Icelandic Meteorological Office. Copyright of this image belongs to Icelandic Meteorological Office.

For now this is just a earthquake swarm and nothing else. Regardless of what happens later. Earthquake activity has been common in this area of the rift zone for several months now. I do not know why that is. The ocean depth in this area is around 3 to 4 km where it is the deepest. So if an eruption takes place there it is not going to be noticed due to the depth of the ocean.

Posted on

Deep earthquakes in Askja volcano

Today (26.03.2013) at 08:09 UTC there where three deep earthquakes in Askja volcano. The most depth of this earthquake swarm was 25.5 km. None of the earthquake had the magnitude above 2.5. The strongest earthquake had the magnitude 2.1 with the depth of 20.4 km

130326_1410
Earthquakes in Askja volcano. Askja is located to the north of Vatnajökull glacier and the lake is round in shape on this map. Marked by the orange dots on it. Copyright of this image belongs to Icelandic Meteorological Office.

This activity is part of an progress that started in Askja volcano back in the year 2010. So far this has not lead to any eruption. But it has created some odd changes. Along one was that Askja lake was ice free last year (winter 2012). The reasons for that are still not known to me.

Blog post updated at 16:32 UTC on 26.03.2013.