Today (21-June-2013) there was an earthquake swarm in Katla volcano, this earthquake swarm took place in the same area where the minor eruption in the year 2011 (July) took place and created a minor glacier flood down Múlakvísl river. So far there is nothing that suggest a eruption is about to take place in Katla volcano, this activity needs to be monitored closely since things can change quickly in Katla volcano.
Earthquake activity in Katla volcano on 21-June-2013. Copyright of this image belongs to Icelandic Meteorological Office.
This earthquake activity in Katla volcano starts around the same time as it did two years ago (2011), but then earthquake activity started on 17-June-2011 and continued until July-2011 and did not end until November-2011. This type of earthquake activity did also take place in June-2012, but no eruption did take place that summer. I expect this earthquake activity to continue in Katla volcano for the time being, sine most earthquake activity always happens during the summer in Katla volcano. It is unclear that is creating this earthquake swarm, it can be anything from pressure changes in hydro-thermal zones in this area, or magma injections at depth, I do not think any dike intrusions have taken place so far in Katla volcano.
Currently there is nothing that suggests eruption is going to take place soon in Katla volcano.
Blog post updated at 22:06 UTC on 21-June-2013.