Modest Fissure Eruption Near Bárðarbunga

Source Icelandic Met Office 

 

UPDATED:  See update at bottom.

 

# 9022

 

The on again, off again RED aviation alert for the Bárðarbunga volcano is on again after a 1.5 km long fissure eruption overnight, but right now it is impossible to know just how disruptive this event is likely to become.  That said, this  eruption appears to be much larger than the small fissure eruption on Friday.

 

For now, a long dyke of sub-surface magma stretches north from the volcano to Askja to the north, which is now on Yellow Alert.

 

A tweet from a team on site from the University of Iceland describes the event:

 

An Olympic-sized pool contains about 2500 cubic meters of water, so the estimated lava flow at this time would fill about 24 pools a minute, or 1440 pools an hour.  Impressive, but at this time, this eruption appears to be smooth, non-explosive, and producing little or no ash.

The Icelandic Met Office – which warned yesterday that an eruption appeared more likely – describes the overnight event as:

 

31st August 2014 08:40 - Eruption in Holuhraun observed 05:15

Observation from scientists in the field (05:15): It appears that the eruptive fissure is longer than in the last eruption. It is extending north and south on the same fissure. The eruption is a very calm lava eruption and can hardly be seen on seismometers (almost no gosórói). Visual observation confirm it is calm, but continuous.

 

Several of the webcams monitoring the event I’ve mentioned in the past appear to be offline right now, but you can watch live (from a distance) on this webcam.

 

Seismic activity in and around  Bárðarbunga continues, with a M5.1 reported within the past hour.

We should see an update from the

Scientific Advisory Board of the Icelandic Civil Protection later today.  Yesterday a fissure eruption was deemed one of the more likely scenarios, although an explosive eruption of Bárðarbunga could not be discounted.

Stay tuned.

UPDATE:  1100 hrs EDT

Although weather conditions are hindering observations, the Scientific Advisory board has released the following update:

 

31st August 2014 12:07 - from the Scientific Advisory Board

Scientists from the Icelandic Met Office and the Institute of Earth Sciences and representatives of the Civil Protection in Iceland attend the meetings of the Scientific Advisory Board of the Icelandic Civil Protection.

Conclusions of the Scientific Advisory Board of the Icelandic Civil Protection:

• A lava eruption started in Holuhraun shortly after 04 AM, on the same volcanic fissure, which erupted earlier this week. The fissure is estimated to be 1,5 km long. It was detected on Míla´s web-camera at 05:51 AM. Fewer earthquakes seem to follow the event than in the previous eruption, but more lava is being extruded.
• At 07 AM the lava flow was around 1 km wide and 3 km long towards northeast. The thickness was estimated a few meters, the flow about 1000 m³ pr second.
• Approximately 500 earthquakes were detected in the area and smaller than before. The strongest earthquake, M3.8 was in the Bárðarbunga caldera. Poor weather conditions prevail in the area, which makes detection of smaller earthquakes difficult.
• GPS measurements show continued movements north of Dyngjujökull.
• Gas emissions rise to a few hundred meters above the fissure.
• Weather conditions make it difficult to follow the progression of the eruption, but scientists are in the area, using every opportunity to acquire information on gas and lava outflow.
• Weather conditions do not allow overflight at this time. The opportunity to fly over the area will be assessed later today.

From the Icelandic Met Office:

The Aviation Colour Code for Bárðarbunga is at ‘red' and the code for Askja at ‘yellow'.

I would note that the latest Aviation Color code map has just recently been changed back to Orange.

Icelandic Met Office: Bárðarbunga Update – Aug 26th

 

 

# 9001

 

Although no surface eruption has occurred, seismic activity under and nearby the glacier-covered Bárðarbunga caldera continues to escalate, with the largest event – an M5.7 quake – hitting last night. 

 

It is still highly uncertain what happens next, but given the history of this particular volcano, no one is ready to relax.

 

In today’s update the Icelandic Met Office presents three possible scenarios ranging from a gradual decrease in seismic activity, to a large scale fissure eruption. 

 

26th August 2014 11:50 - from the Advisory Board of scientists

Scientists from the Icelandic Met Office and the Institute of Earth Sciences, and representatives of the Civil Protection in Iceland, attend the meetings of the Advisory Board.

The following points were the conclusion at a meeting of the Advisory Board today:

• Intense seismicity continues. Over 500 events have been recorded since midnight.
• Seismicity continues to migrate northward. Seismicity is now concentrated on the 10 km long tip of the dike extending 5 km beyond the edge of the Dyngjujökull glacier.
• At 01:26 this morning an earthquake of magnitude 5,7 was observed beneath the Bárðarbunga caldera.
• The dyke beneath Dyngjujökull is now thought to be close to 40 km long. Modelling
  of GPS data indicates that about 50 million cubic meters of magma have added to the volume in the last 24 hours.
• There are no indications that the intensity of the activity declining. The following three scenarios are still considered most likely:
• • The migration of magma could stop, accompanied by a gradual reduction in seismic activity.
  • The dike could reach the surface of the crust, starting an eruption. In this scenario, it is most likely that the eruption would be near the northern tip of the dyke. This would most likely produce an effusive lava eruption with limited explosive, ash-producing activity.
  • An alternate scenario would be the dyke reaching the surface where a significant part, or all, of the fissure is beneath the glacier. This would most likely produce a flood in Jökulsá á Fjöllum and perhaps explosive, ash-producing activity.
• Other scenarios cannot be excluded. For example, an eruption inside the Bárðarbunga caldera is possible but presently considered to be less likely.

From the Icelandic Met Office:

The Aviation Color Code remains at the "orange" level.

26th August 2014 06:45 - from geoscientist on duty

Seismic activity continues to be high.

Biggest earthquake in the current swarm was measured this night at 01:26. According to USGS the magnitude was 5.7. The event was localized in the northern/northwestern part of Bardarbunga caldera at 6 km depth.

Most of the seismic activity is close to the rim of Dyngjujokull. The dyke is still migrating to the north and the tip of it is already around 10 km outside of the glacier. Most of the events are at the depth of 8-12 km.

There have been no signs of harmonic tremor.