Saturday, May 11, 2013

More rumblings in Iceland

At the beginning of April there was a burst of earthquake activity just off the northern coast of Iceland, and while it occurred offshore there was no evident major disruption. Now there has been a similar flurry of activity down along the southwest corner. (Ed note This was corrected on May 13, h/t to Steve Golson for catching the error which had east and west mixed up). This contained a number of quakes that ran up to around 4, but it also now seems to be slowing down a little.

Figure 1. Earthquakes in the last 24 hours around Iceland (Icelandic Met Office )

Jón Frímann has written a post pointing out that the activity seems somewhat cyclic, and that the last significant events were in either the 18th or 19th centuries, with no indications of any imminent danger.

Both the current events and the ones at the top of the island lie on the Mid-Atlantic rift that runs through the island, and marks where two of the earth’s plates are slowly drifting apart.

NOTE: This post was updated on Sunday, May 12th.

Figure 2. Map of Iceland showing major volcanoes (The Times of London)

However, you may note on the earthquake map that there is also a little current activity around Katla, which is the volcano that I have been expecting to be the next to erupt, after the pattern of quakes that has occurred there over the past couple of years.

Over at Volcano Café the suggestion has been made that, instead of Katla, it will be the neighbor Hekla that will go next, since there was sufficient activity there to warrant a warning to the public in March. That has since been withdrawn, after the region returned to quiescence. Yet there continues to be some activity in the Katla caldera.

I must continue to remember that imminent in geologic terms does not necessarily mean this month.

Figure 3. Relative positions of Hekla and Katla (which is under Mydralsjokull) (Icelandic Met Office)

UPDATE (Sunday 12th May). While the overall intensity of the quakes it diminishing, I can't help note that they are now extending along the rift line, and taking a straight shot at Hekla.

Figure 4. Earthquakes in Iceland leading up to noon 12th May 2013 (Icelandic Met Office)