VONA message

Grímsvötn

Time: 06. Dec 2021, 08:38 GMT

Color code:  Orange 

Volcano id: 373010

Activity summary:
The glacial flood from Grímsvötn reached its peak discharge yesterday morning (05.12). The ice-shelf in Grímsvötn has subsided 77 m since the flood started and the rate of the subsidence has decreased significantly since yesterday. The discharge in Gígjukvísl river was measured twice yesterday, 2800 m3/s around noon and 2310 m3/s in the afternoon. Therefore it is assumed that the maximum discharge of the glacial flood was reached yesterday morning. The seismic activity at Grímsvötn has been increasing above the normal level since the last couple of days, and this morning an event of ~M3-3.5 was measured at 6:16 UTC and a M2.3 a minute before. Three other earthquakes around M1.0 have been detected in Grímsvötn this morning. No volcanic tremor has been detected and no increase/changes in geochemical emissions at the volcano are measured. This seismic activity is possibly occurring due to the decreased pressured above the volcano, since the flood water left Grímsvötn sub-glacial lake. According to calculations from the Institute of Earth Sciences at the University of Iceland at least 0.8 km3 of water have drained from the sub-glacial lake. Due to this elevated seismic activity the IMO has decided to raise the aviation color code from Grímsvötn volcano from Yellow to Orange. The IMO will continue to monitor the seismic activity at Grímsvötn volcano closely and send out an update if the situation there changes.

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






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