Monday, January 3, 2011

Volcanoes in Iceland - an update

Last April air traffic between North America and Europe was stymied because of the eruption of the volcano at Eyjafjallajokul in Iceland, and, based on historic patterns, there was a suggestion at the time that this could lead to the much larger eruption of the adjacent Katla which lies under Myrdalsjokul about 18-months later.

Out of curiosity I have been keeping an intermittent eye on the Icelandic Met Office site that monitors earthquakes in that country, since that time. Iceland gets more than its share of earthquakes since it sits on the edge of plates that are slowly moving apart, and there are, as a result, several dozen small quakes along the rupture lines every day. To get some sense of what has been happening I decided to keep a list of those of magnitude 3 and higher – and these only occur about every 2-3 days so that it has not been as much of a chore. There have been some 78 of these since I first started the list, with the latest (at 3.8) yesterday. (The list is given at the bottom of the cited post, and I amend it as new quakes occur).

The activity down at Eyjafjallajokul has died down considerably, but I did note that the recent activity has been along a couple of planes that take the path to Katla a bit further than earlier quakes. We are still about eight months away from the historic pattern, but it will be interesting to see how the situation develops over that time.

One other thing of interest is that the fissure line runs North-East from Katla, but before it gets to the next major site of quakes, (where the yellow star sits in the plot below) it passes through a region where there has been little activity over the past year. Sometimes it is these quiet zones that lead to the most violent subsequent quakes.

Recent Icelandic quakes, (Icelandic Met Office) only those above 3 get a star, such as the yellow one that shows where the one yesterday occurred. The red arrow shows that zone that has been fairly quiet.

We are travelling at the moment, so the OGPSS post will be delayed a little this week – my apologies.

1 comment:

  1. Have you seen the map from the Met Office today? Lots of activity though not concentrated in a small area.