Gjalp subglacial eruption (3 October, 1996). Photo taken by Oddur Sigurdsson, Iceland Geological Survey. See an airplane in the photo for scale. Photograph and text from http://rses.anu.edu.au/~hrvoje/Bardarbunga.html

Bárdarbunga, Gjálp and Onwards

Lately Iceland has suffered a long series of earthquake swarms that have ambled all over the island. Earthquake swarms are common in Iceland, that is not the issue, the problem is that they this time came in a swarm of swarms, all of them containing at least one earthquake above M3. Before we take a…

View from Askja towards Herðubreið with Herðubreiðartögl to the right. Notice the youngish lava field in the forefront. Photographer unknown, click on the image for details.

Update on Herðubreið

The earthquake swarm at Herðubreiðartögl has now continued unabated for four days without a letup, during the first two days there were 4 earthquakes above M3 with the largest earthquake at M3.9 and by now the count of earthquakes has passed 1 000. As such this is not the largest earthquake swarm to hit this volcano,…

Picture taken over the Blue Lagoon towards the Svartsengi Powerplant. On the other side is the Svartsengi volcano.

Magmatic or Tectonic Earthquake?

I get this question often about Iceland, especially when there is an earthquake swarm. The problem is that it is rarely clear cut if it is magmatic or tectonic when it happens in Iceland. First of all you have all of the rift zones being tectonic, but they are also subject to rift and hotspot…