Day: March 25, 2011

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False alarm at Grímsfjall volcano [updated]

I really did think that something was going on at Grímsfjall volcano today. There was something going on. But whatever it was. That does not appear to be volcanic or related to any volcanic activity so far. Most likely this was a change to hydrothermal activity in Grímsfjall volcano or some movement of the ice covering Grímsfjall volcano close to the seismometer on top of Grímsfjall volcano.

But so far Grímsfjall volcano remains quiet.


Picture is from the web site of Icelandic Met Office. Copyright of this picture belongs to them. Click on the picture to get full size.

The change in the tremor plot can be seen at the end of this tremor plot from the web site of Icelandic Met Office.

Update: This odd behaviour on Grímsfjall seismometer continues. So I am wondering if the false alarm might not be so false after all. But a eruption is not starting. It lacks the earthquakes of a magma pushing it’s way up the crust. But there is something going on at Grímsfjall volcano. That is for sure.

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Strong earthquake swarm north of Kolbeinsey Island

There seems to be a rather large earthquake swarm taking place north of Kolbeinsey Island. This earthquake swarm started earlier today (24. March 2011). But do to how far it is away from the SIL monitoring network it is hard to know for sure how strong this earthquake swarm actually is. It is also clear from the data that only the largest earthquakes in this swarm are appearing on the Icelandic Met Office web page.

This earthquake swarm might be part of Kolbeiney Island ridge or part of the SPAR fracture zone that is north of Kolbeinsey Island ridge. It is hard to know for sure due to how poorly this earthquake swarm is being recorded by the SIL network. The largest earthquake so far is a ML3.6 at 9.0 km depth (automatic data, not reviewed). But the SIL network can detect earthquakes in this there down to the size ML2.5, but nothing less then that it appears.