The earthquake activity in Herðubreið during past few days is not volcanic in nature, or magnetic in nature. It is purely tectonic in nature. But the faults that have been moving are vertical, not horizontal as so many earthquake faults. Earthquakes are common in this area, as it on the eastern rift zone. The fault lines in this area of Iceland are highly active at times. Iceland Metorlogical Office has released this interesting information about the earthquake activity in this area during the past few years.
The first fault plane in Herðubreið. This one has the direction of N41°A. Copyright of this image belongs to Iceland Meteorological Office.
The second fault plane in Herðubreið. This second fault has the direction of N221°A (49°). Copyright of this image belongs to Iceland Meteorological Office.
Most of the earthquakes are on the depth of 5 to 6 km according to IMO.
The earthquake activity in Herðubreið the days 14 to 17 of May 2012. Copyright of this image belongs to Iceland Meteorological Office.
Earthquake activity in Herðubreið during the years 2005 to 2006. Copyright of this image belongs to Iceland Meteorological Office.
Total amount of earthquakes in Herðubreið from the years 2005 to 2012. This clearly shows that activity in this area has been rather constant during this period. Copyright of this image belongs to Iceland Meteorological Office.
The area in question is outside Askja volcano main fissure swarm. It is also outside Kverkjföll volcano main fissure swarm. So this earthquakes are tectonic in nature. But even so this area has erupted in the past. But for now. It is just earthquakes and not magma on the move, or breaking its path up to the surface as was case in Upptyppingar tuff mountain. The images are from Week 20 overview (what is up about it) at IMO web site.
