Carl le Strange says:
October 5, 2012 at 16:15
Okay, I have gone through the earthquakes NNE of Grímsey.
Since I am not Lurking I can’t do a nice plot of it. But something is definitly moving those quakes upwards, the average depth get lower all the time.
If you look at the map in the link you can see the volcano marked ESE, E to NNE of Grimsey.
[link to en.vedur.is
No, known eruption the NW of Grimsey, but it at an odd spot of the Grimsey Oblique Rift (GOR), but there is a marked uplift there from the rift depressed valley. It is most likely a central volcano that is unrelated to the other in NVZ.
Another thing I just found out. Theistareykirs known historic activity started with an uneruptive rifting episode in 1618.
[link to earthice.hi.is
Now over to Brandsdóttir:
“Four left-stepping, en-echelon, NS-striking rift segments
(volcanic systems) exist along the GSZ.” There you have it, there are no less the for volcanoes withing the Grimsey seismic zone. Fun to be had. And as we move into the Husavik Flatöy Fault it gets even more interesting, “The southwestern margin
of the fault is characterized by NE-striking lavas which dip steeply (30–50) towards
Eyjafjarðaráll. The lavas are dissected by en echelon arrays of conjugate strike-slip
faults intersecting the HFF fault at angles of N20–30W and N20E. Some can be
traced onto land where they exhibit complicated flower patterns.”
[link to meetings.copernicus.org
So, the harmonic tremor in the HFF a couple of days ago was probably magmatic movement following the mainly tectonic medium sized earthquake swarm last week.
The current earthquake activity in the GSZ is most likely a series of seismic rifts with following magmatic emplacements. Or in laymans terms. We might have a run up for a volcano we do not even have a name for.
[link to volcanocafe.wordpress.com