Increase in earthquake activity in Hamarinn volcano (Bárðarbunga volcano)

Over the last few days there has been increase in earthquake activity in Hamarinn volcano (Bárðarbunga volcano). In Global Volcanism Program record this area is known as Loki-Fögrufjöll. Largest earthquakes today (12-August-2019) had a magnitude of 2,8 and 2,5 and other earthquakes have been smaller in magnitude.

The earthquake activity in Hamarinn volcano (red/blue dots at the edge of the glacier). Copyright of this image belongs to Icelandic Met Office.

Last time Hamarinn volcano had this type of earthquake activity it erupted for few months after it had started. That was on 12th July 2011. I wrote about those events here and here (glacier flood that followed, July 13th 2011). There were minor additional eruptions in August and November in 2011 according to the tremor data, those eruptions only lasted for ~4 hours at most. Since then this area has mostly been quiet and did drop down in activity after the eruption in Bárðarbunga volcano in 2014 to 2015.

It is unclear what is going on in Hamarinn volcano, for now there is no eruption taking place and any eruption is going to appear clearly on harmonic tremor data on the SIL network. It seems that eruptions in Hamarinn volcano start without any earthquake activity, I don’t know why that is. Last major eruption in Hamarinn volcano took place in the year 1910 from June 18 to October.