Today (21-November-2013) an minor earthquake swarm took place in Þórðarhyrna volcano. All of this earthquakes were small, with the largest having just the magnitude of 1,9. Depth of this earthquakes was from 6,0 to 0,1 km. This minor earthquake activity is now detected for the first time due to a new SIL stations in the area. How long this type of activity has been ongoing is impossible to know since in the past there have been fewer SIL stations in the area.
Earthquake activity in Þórðarhyrna volcano. Copyright of this image belongs to Icelandic Meteorological Office.
This earthquake activity is not ice-quake activity, since the glacier is frozen now and with temperature down to -19C it is not going to move a lot. Last eruption in Þórðarhyrna volcano was in the year 1910 and it was connected to an eruption sequence that took place in Grímsfjall volcano at the same time (or that is at least the theory).
I am not yet sure what this means long term for activity in this volcano, since I know so little about how this volcano works due to lack of documented eruption history. If this earthquake activity intensifies from what is now taking place there is a small chance of something happening in Þórðarhyrna volcano. For the moment however, this is just a minor earthquake swarm and does not mean anything special. There have not been any changes in harmonic tremor on SIL stations close to Þórðarhyrna volcano.