Iceland: Four day long earthquake swarm intensifies at Krísuvík volcano

Jón Frímann
jonfr.com
Fri, 25 Feb 2011 11:14 UTC

Picture is from Icelandic Met Office graphic web tool.

While this earthquake swarm in Krísuvík volcano does not appear to be big in size. It is clear that was rather long and might even be ongoing. But it is interesting how long this earthquake swarm did last. So far the time is about 2 days. It is impossible to know if the earthquake swarm is over or not. Current number of earthquakes is about 60 earthquakes so far.

The earthquakes are on North-South fault line according to the visual evidence. Depth of the earthquakes is from 12 km and up to 3 km at the moment. It is hard to know at the moment if this is due to magma inflow under Krísuvík volcano or just normal tectonic activity along the rift zone in Reykjanes.

Icelandic news about this earthquake swarm.

Hrina smáskjálfta í Krýsuvík (Vísir.is, Icelandic)

Update: February 27, 2011

Large earthquake swarm in Krísuvík volcano

After four days of continues earthquake activity it appears that Krísuvík volcano has stepped up it's activity by a order of magnitude. Since midnight there have been over 400 earthquakes in Krísuvík volcano. The activity is continuing when this is written and does not show any signs of slowing down at this moment. Geologist in Iceland are expecting more earthquakes in this area over the next hours and even earthquakes that are larger then ML3.0 in size.

The largest earthquakes where ML3.3 and ML3.7 in size. This is automatic size by the SIL system. The depth of the earthquakes was 4.7 km and 1.1 km according to the automatic SIL system. Due to high number of earthquakes the SIL system is putting earthquakes down all around the Reykjanes Peninsula. While there might be some earthquakes there, the number is not nearly as high as can be seen on the map. The earthquakes can be located by there low quality number.

Given the location and how this earthquake swarm is behaving it is my opinion that this is due to a magma is pushing up the crust in this area. But it remains a question of this is going to start a eruption or not. But the chances are growing for as long as this earthquake pattern holds up in Krísuvík volcano. If a eruption starts in Krísuvík volcano it is going to one of Hawaii type eruption, unless it is under water then it is going to be explosive for as long there is water getting into the crater. Last time there was a eruption in this area a 25 km long eruption fissure did form.

For now however all that can be done is to wait and see what happens. This earthquake swarm is going to continue for the next few hours and even days. The largest earthquakes can be seen on my geophone sensors here.