Odds Of Eruption Decrease As New Data Suggests Magma Is Solidifying Underground Skip to content

Odds Of Eruption Decrease As New Data Suggests Magma Is Solidifying Underground

By Gréta Sigríður Einarsdóttir

Photo: Golli. The country’s most recent lava field by the Fagradalsfjall eruption on the Reykjanes Peninsula. .

While there’s still seismic activity around the new magma intrusion by the former eruption site on the Reykjanes peninsula, it has decreased significantly, and new data indicates that the magma might have begun to solidify underground. Scientists have speculated on the similarities of the current activity in Reykjanes with the 1975-1984 Kröflueldar, where several magma intrusions formed but only some of them reached the surface in volcanic eruptions.

GPS station movement close to Geldingadalir, the former Reykjanes peninsula eruption site, has decreased significantly. The movements indicate deformation in the surface but almost no movement has been detected since December 28. Seismic activity is still considerable but has decreased substantially since the earthquake swarm began December 21 in connection to the new magma intrusion underneath Fagradalsfjall.

Models indicate that the magma intrusion is about half the size of the one created in the leadup to the Geldingadalir eruption, around 18 million m3. They also believe the top of the magma intrusion has reached a depth of 1,5 km. Experts have been uncertain if the magma in this intrusion will reach the surface like the one in March. Models and latest measurements indicate that the magma has begun to solidify and the longer time passes without changes in the activity, the lesser the chance that the magma intrusion will culminate in a volcanic eruption.

“Scientists have compared the activity in Fagradalsfjall to the activity in the Kröflueldar eruption,” stated Michelle Parks, a specialist with the Iceland Met Office, who has worked on analysing the data. “In the Kröflueldar eruption, about half the magma intrusions ended with an eruption and others didn’t. We could be seeing an example of such an activity in Fagradalsfjall. The size of the magma intrusions and their depth will have an influence,” she stated.

While there’s no new eruption yet, there’s still considerable heat in the new lava field by the former eruption site. On cold days, steam rises from the lava field but the Met Office notes that this is not an indicator of increased activity.

Scientists will continue to monitor the area and are awaiting new satellite images later this week that will cast a new light on how things are progressing at Fagradalsfjall.

Kröflueldar, which loosely translates as the Krafla fires, were a series of magma intrusions and volcanic eruptions in Krafla in northeast Iceland from 1975-1984. Magma would continually flow into the magma chamber underneath the volcano, and when the pressure was sufficient, magma would be pushed into fractures, creating magma intrusions, which sometimes led to volcanic eruptions. This happened 24 times over the nine-year period, with nine of the magma intrusions leading to eruptions. The underground magma also caused the land to rise and sink causing seismic activity in the area.

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