Sunday, 31 August 2014

New eruption: 60 m high lava fountains

The effusive eruption in Holuhraun that started early this morning is producing 50 - 60 meter high lava fountains, according to a volcanologist at the site. The active fissure is 1500 - 1800 meter long, considerably larger than the fissure that opened Friday morning.

According to Armann Hoskuldsson, volcanologist at the University of Iceland´s Institute of Earth Sciences, who is at the site, the lava flow from the fissure is about 10-20 times more than Friday morning. The eruption is estimated to be 10 to 20 times bigger than the one Friday morning, and looks "robust" says Dr. Hoskuldsson. He says the highest lava fountains can be seen at the southern end of the fissure, but at the northern end, they are less powerful. The southern end of the fissure is about 4 kilometres north of the Dyngjujokull outlet glacier.

The Civil Protection Agency has maintained its level of preparedness at "danger", and previous road closures and area restrictions are in effect.

This effusive fissure eruption is the third one in the area since last weekend. On Aug. 23, a small subglacial eruption occurred near the Bardarbunga caldera in Vatnajokull. The eruption was shortlived, and did not break through the glacier, but did create calderas that were spotted a few days later. Early last friday, a small fissure opened in the Holuhraun lava field, north of the Dyngjujokull outlet glacer. That eruption lasted for 3 - 4 hours.

Seismic activity has been detected in the Bardarbunga region this morning, but less intense than in recent days. Today, the weather conditions are very unfavorable north of Vatnajokull, with high wind and rain forecast for today. Here is a webcam near the eruption site, but due to fog and rain, visibility is sometimes very limited.

Eldgos hófst í Holuhrauni, norðan Vatnajökuls, rétt fyrir klukkan sex í morgun. Þetta er þriðja gosið á Bárðarbungusvæðinu á rúmri viku. Gosið er hraungos, á sömu sprungu og opnaðist aðfaranótt föstudags, en gosið nú er 10-20 sinnum stærra, að sögn Ármanns Höskuldssonar eldfjallafræðings, sem skoðaði gosstöðvarnar í návígi í morgun. Hann segir að hæstu hraunstrókarnir séu allt að 50-60 metra háir, syðst á sprungunni, en mun lægri norðar. Suðurendi sprungunnar er á sama stað og aðfaranótt föstudags, um fjóra kílómetra frá sporði Dyngjujökuls.


Friday, 29 August 2014

Holuhraun eruption lasted 3-4 hours

The fissure eruption in Holuhraun lava, north of Vatnajökull glacier, which started at midnight, is already over. The eruption lasted for about three or four hours, according to Páll Einarsson, professor geophysics at the University of Iceland.

"It was a small eruption and a small sample of the magma that is moving underground reached the surface," says Páll, describing the events of the night as an abberation in the larger course of events of the last two weeks.

Páll agrees with fellow professor of geophysics, Magnús Tumi Guðmundsson, who earlier today described the eruption as an "accident". "The magma intrusion strayed unnecessarily close to the surface and some magma came out," Páll says.

The Icelandic Met Office has downgraded the aviation alert over the volcanic eruption area from red to orange. There is not considered to be a risk of volcanic ash reaching the atmosphere.

The Icelandic Transport Authority has also reduced the restricted flight area around the volcanic activity from 10 nautical miles (NM) to 3 NM and 5,000 foot altitude. The warning area restricting instrument flight rules flight remains unchanged.

The eruption fissure is about 5 kilometers from the Vatnajökull glacier. The fissure appears to be about 1 kilometer long. The lava is thin and flowing quickly southeast towards the glacier.


An small eruption in Holuhraun

A fissure eruption started around midnight in the Holuhraun lavafield, ca. 9 kilometers north of Dyngjujokull glacier. Lava streams out of a 100 meter long fissure, in the northern part of the lava field, about 15 kilometers south of the Askja caldera. IMO has issued a ONLY orange alert for aviation (there is no danger, it is a small eruption).

The eruption seems to have started near the northern end of the magma intrusion that has been propagating northward from the Bardarbunga caldera since August 16.

Small surface crevasses were seen in the Holuhraun lava field yesterday, leading to increased interest among scientists. The possibility of an eruption migrating southwards, towards the Dyngjujokull glacier cannot be excluded at this time.

Benedikt Ofeigsson, staff member at the Icelandic Met Office is at the scene. In an interview with RUV tonight, he described the eruption as small; lava is flowing to the southeast and some small tephra mantles are coming out of the fissure.

The IMO has issued a red alert (highest) for aviation. That means that airtraffic is restricted in a large area around the eruption. The fissure lies on a northeast - southwest direction.

A live webcam of the eruption can be found at Road and area restrictions that have been enforced over the last days are still in effect in the area north of the Vatnajokull glacier.

The situation is not serious and is a small eruption. There is a tour company that is already offering a tour to go see the volcano.

Jóhanna & Kolla
Iceland24, August 2014

Wednesday, 27 August 2014

Seismic activity near the Askja caldera

A 4,5 Magnitude earthquake occurred just east of the Askja caldera at 01.52 GMT this morning and strong seismic activity has been detected south of Askja in recent hours. The dike intrusion is believed to have reached a lenght of more than 40 kilometers to the north, towards Askja.

Models of the intrusion, based on GPS measurements of land deformation and earthquake resolutions, indicate that about 20 million m³ of magma have entered the intrusion over the last 24 hours; 3-400 million m³ since the beginning of the episode, on Aug. 16. The intrusion also seems to have caused considerable stress in the bedrock over a large area, including the vicinity of Askja. According to scientists at the Icelandic Met Office, that could explain the 4,5 event near Askja this morning. Most of the seismic activity has however been concentrated near the intrusion, north of Dyngjujokull outlet glacier.

„The 4,5 Magnitude earthquake near Askja was duly noted,“ says Magnus Tumi Gudmundsson, professor of geophysics at the University of Iceland. „Our interpretation of that event is that this is a reaction in the rock strata to the intrusion coming from the south. It causes tension, but the earthquake does not signify an impending eruption in Askja.

This is a very interesting sequence of events; big news really in a geological context, even though an eruption has´nt happened yet, and hopefully will not happen. We are looking at the active rift between the plate boundaries in the middle of the country, where much of the volcanic activity has taken place. This particular area has been relatively quiet in recent decades; an intense episode like this has probably not happened for the last hundred years, perhaps not even two hundred years.

How much has the land spread? 

„It´s difficult to say precisely. The intrusion is perhaps 2 - 3 meters wide, but that does not mean that the distance between Egilsstadir and Reykjavik has increased by that; rather the island is being pulled apart, and the landmass on either side is pushed together. But locally, down in the crust, the rock has been cleaved.“