During the past two weeks there have been tremor pulses in Hamarinn volcano (is claimed to be part of Bárðarbunga volcano system), at least most likely that volcano. But it might also be a volcano that I call Skrokkalda Volcano (other name might be Hágöngur volcano) (it has no entry on GVP web page, I do not know why). But given recent history I find it unlikely to be the case.
This harmonic tremors might be due to dike intrusions. I find it unlikely to be from a man made lake called Hágöngulón that is in this area. The harmonic tremor pulses look like sharp spikes on the tremor plot on the Skrokkalda SIL station.
This pattern of harmonic tremor spikes was seen all last year and all of the year 2009 from what I can remember. I do not have tremor charts from that period. But however this suggests that more magma has now started to flow into Hamarinn volcano. But there was a small volcano eruption (it seems so, given the flood that took place in July) in Hamarinn volcano last summer (summer 2011). What happens next is a good question.
This process of inflow of magma seems to without earthquakes, or close to it. I do not know why that is and I have no ideas that explain it.