VONA message

Grímsvötn

Time: 10. Oct 2022, 15:23 GMT

Color code:  Yellow 

Volcano id: 373010

Activity summary:
Recent measurements of the height of the lake in Grímsvötn by GPS instruments show that water has started to drain. This is believed to be the beginning of what is expected to be a minor jökulhlaup. The outflowing water has not yet reached the edge of the glacier, meaning that the water is still travelling under the ice. There are currently no indications of volcanic tremor or elevated seismicity around Grímsvötn and the gas monitoring station does not show changes in the emission composition. Volcanic activity at Grímsvötn has, however, been gradually increasing over time, primarily indicated by surface deformation which exceeded the level it was at prior to the 2011 eruption back in 2020 and continues to rise. The other geophysical and geochemical parameters have intermittently shown elevated signals above the known background level; most notably there was a pulse of seismic tremor at Grímsvötn that lasted for about one hour last week and magmatic gases were measured in the mostly geothermal emissions in the summer of 2020. As the volcanic activity is above background levels and the occurrence of a flood might trigger an eruption in the coming days/weeks, the aviation color code is being raised from green to yellow. This does not mean that an eruption is imminent, but an eruption could be triggered by depressurization by the anticipated jökulhlaup or occur regardless, possibly (like in 2011) with very weak precursory activity and short warning time. The conditions at the volcano may change at any given time and the volcano may return to normal background conditions without further escalation.

Cloud height:
No eruption ongoing.

Other cloud information:
No eruption ongoing.

Remarks:
More information about Grímsvötn volcano, its past eruptions and associated volcanic hazards is available at the link: http://icelandicvolcanoes.is/?volcano=GRV