Today (29-October-2014) marks the two months since the second eruption in Holuhraun started. Currently the eruption is ongoing with no signs of stopping, it is erupting about the same power since Monday, the eruption power is less than it was when it started two months ago and that is normal. The lava field has now covers area of 64,6 square kilometres in size. This is now largest lava in Iceland since Laki eruption of 1783 – 1784.
Earthquake activity in Bárðarbunga volcano for the past 48 hours. Copyright of this image belongs to Icelandic Met Office.
Earthquake activity remains strong in Bárðarbunga volcano. There is one to two magnitude five or stronger earthquake every 20 – 35 hours at present time. The caldera continues to drop around 40cm/day, most of the drop happens without any earthquake activity at all. So far no major eruption has happened under the glacier, only minor eruptions have happened that have only lasted for few hours.
I also want to point out there is only basalt lava in this eruption. This magma is up to 1600C warm when it comes up from its deep source at +20km depth. If there was any other type of magma in this eruption it would have been detected by now in the current eruption in Holuhraun. Most of Iceland eruptions are basalt only eruption, since Iceland is both on hotspot and the mid-Atlantic ridge. There are other melts and types of eruptions, but such eruptions don’t happen as frequently as normal basalt eruptions. The reason for ash cloud eruptions in volcano like Grímsfjall is due the fact that there is a glacier on top of the volcano. Same rule applies to Katla volcano, it is all basalt most of the time, but since there is a lot of glacier on top of the volcano the eruptions that happen are explosive due to that fact.
I don’t think there is anything else new about the eruption and activity in Bárðarbunga volcano since Monday.