In the last two days, there have been significant changes in the glaciers and volcanoes in Iceland. There has not yet been an eruption, but the melting of ice indicates that additional heat is reaching the surface. The pattern of earthquakes has also shifted.
Scientists from the Icelandic Meteorological Office and the Institute of Earth Sciences, together with representatives of the Civil Protection in Iceland, met today to discuss the on-going unrest at the Bárðarbunga volcano. A flight over Bárðarbunga revealed large crevasses, totaling about 5 kilometers in length. These crevasses are probably the result of melting at the bottom of the glacier, about 500 meters below the surface. And that melting, in turn, stemmed from heating at the base as magma rose, or even came into direct contact with the ice. It is possible that the extensive earthquake activity also contributed to the crevasses. Instruments reveal that a lake located beneath Grímsvötn Glacier has risen about 5-10 meters, another sign of melting. Future events will help clarify the role of these different processes.
The pattern of earthquakes reveal that magma has been moving to the northeast from Bárðarbunga, pushing ahead through a dike (an underground fissure). Seismic activity is increasing around the Askja volcano, and GPS measurements show that the surface is being pushed upward there. Aksja is located in the rainshadow of other mountains. Since it receives less snow, it does not have a glacier on its summit.
The earthquake map shows a line of activity stretching Bárðarbunga from to the northeast. The green stars are the quakes of magnitude 3.0 or greater; the group to the upper right in the set are close to Askja. The most recent quakes—indicated in red—are also in that section.
As a result, the aviation warning code for Askja has been elevated from green to yellow, so there are now warnings for two volcanoes in the area. The Department of Civil Protection has notified nearby residents of the increased risk of flood, and organized community meetings to discuss possible responses.