During the week there has been a swarm of minor earthquakes in Askja volcano. All of the earthquakes have been small and none have reached magnitude 2,0 far as I know.
Askja volcano is the volcano most south on this image (the volcano on the end). Copyright of this image belongs to Icelandic Met Office.
There is nothing suggesting that current earthquake swarms are due to magma movements at shallow depths. This is rather hydrothermal activity changes in the volcano due the it being warmed up by new magma entering it and warming up groundwater inside the volcano. That has happened before in earlier eruptions and is documented, the time scale of such changes is not documented far as I know.
Askja volcano started for prepare for an eruption phase in 2010, so far nothing suggest that an eruption is imminent, but it remains a question if the push from Bárðarbunga volcano has changed anything in Askja volcano.
Article updated at 18:56 UTC.
Yesterday (01-May-2015) a minor dyke intrusion took place in Katla volcano. This dyke had depth down to 26,9 km and up to 18,5 km. This is the second dyke intrusion in this are in short space of time. Largest earthquake in the following earthquake swarm had the magnitude of 2,0.
Dyke intrusion in Katla volcano (dense cluster of earthquakes). Copyright of this image belongs to Icelandic Met Office.
While this doesn’t signal imminent eruption in Katla volcano this activity does have me concerned due to past experience with activity in Katla volcano. This might die out, but there is no way to know for sure. All that can be done is to wait and see what happens next in Katla volcano.
Notice on Grímsfjall volcano
There has been a slight increase in earthquakes in Grímsfjall volcano. This suggest that the volcano is about to be ready for its next eruption. Earlier eruptions took place 2011, 2004, 1998 … etc. It is impossible to know when or how big next eruption in Grímsfjall volcano is going to be.