The activity of Öræfajökull is now typical of volcanic eruptions.
After the consultation meetings with the Icelandic Meteorological Office, the Earth Sciences Institute of the University and Public Security, as well as the inhabitants of Öræfasveit, the current position of Öræfajökull has been compiled.
Current position of Öræfajökull
The mountain has extended since the beginning of 2016-17. The expansion is accompanied by increased earthquake activity and deformation, which occurs in the processing of satellite data and GPS measurements. The cause of the expansion is considered to be the insertion of a new magma at the root of the volcano, which builds pressure inside the mountain.
There is no indication that the velocity of the expansion is decreasing, on the contrary, there is evidence that the velocity of the expansion, which probably reflects the speed of the influx of magma, has increased slightly since the summer.
Earthquake activity this year has never been greater since measurements began and has increased slightly since the summer. Both are now measuring more earthquakes, but they are larger and more energy-intensive. In other words, this autumn, more earthquakes of the size M1,5 to M3 are forecast now than before. The earthquakes preferably align themselves with the caldera rim, suggesting movements on the perimeter of the caldera rim.
Apparently the power of the geothermal area, which formed a 20 m deep sealant in the middle of the Öræfajökull reservoir, was significantly reduced in November last year. The satellite image of the glacial surface from October 4 shows insignificant changes, other than those that can be connected to a normal season. Measurements in Kvíá, both conductivity measurements and analyzes of samples, indicate that this year has gradually decreased the amount of geothermal water that mixes the glacial water. Measurements of the depth of the boiler show that it reached its highest depth in December last year and has then decomposed (at least 10 meters). Ice surveys conducted in June 2018 show no water collection under the cat. It is therefore unlikely that the icebox collects water. A new measurement of the depth of the boiler will be done in November.
Resistance measurements this spring show geothermal formation at a small depth inside the Öræfajökull caldera. The measurements indicate the existence of a high-temperature system, similar to that seen in many main stations in Iceland.
Chemical analysis of Kotá samples indicates that it is mixed geothermal water as it has been. Svínafellsá shows no geothermal mark, and Virkisá shows a similar situation as it has been.
The simultaneous interpretation of the current measurements today indicates that the concentration of nitrogen is about 3 to 8 km deep. It builds up pressure inside the mountain and causes expansion and earthquake activity on circular oscillations. Geothermal power under the sieve has decreased significantly. Possibly, the rapid increase in geothermal energy in November and December 2017 was due to the effect of the magnet on the roots of the geothermal system, after which the system reached a new equilibrium with a similar heat output as before. In addition, as a result of increased access to groundwater, the top layers of the mountain have cooled the top of the geothermal system.
Possible development
The activity of Öræfajökull is now typical of volcanic eruptions. The activity can stop before a gossip occurs, but nothing can be said at this stage.
One possible consequence of current development is that the activity still grows and end with volcanic eruption, but it can not be said when it would be.
It is not possible that more magma deposits are formed into the mountain. This could affect geothermal power and increase the risk of jogging.
Below you can read more about the monitoring of Öræfajökull and also the graphs and further explanation of the function at the volcano.
Image above: Significant signs of overheating in Öræfajökull.