Katla volcano (Iceland): harmonic tremor could indicate a small eruption
Monday Feb 20, 2012 23:53 PM | BY: T
Volcanic tremor (a low frequency vibration often caused by magma rising to the surface) has been observed under Katla volcano in southern Iceland, Jón Frímann reports on his Iceland volcanoes blog (see below), closely following seismic activity in Iceland recorded both by national instruments and his own private geophone network.
According to Jón, there are 2 possible explanations: one could simply be an increase in hydrothermal activity in the northern part of Katla volcano.
The second could be magma movements at depth although there have been no significant earthquakes that usually would accompany an intrusion or small (sub-glacial) eruption, although this still could occur in the near future as often observed in the past during similar episodes of tremor followed by earthquakes.
The last minor eruption at Katla volcano was on 6 September 2011, and caused a small glacial flood.
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Thursday, Feb 16, 2012
Two of Iceland's most known and active volcanoes are showing signs of unrest. Another seismic swarm (after the last one around 3 Feb) occurred at Katla volcano yesterday, although it was weaker than the previous ones. Most likely, the swarm was caused by another shallow dike injection (magma intrusion) beneath the crater, confirming the ongoing unrest at the volcano. ... [more]
Sunday, Feb 05, 2012
Small seismic swarms have occurred near Katla volcano (S Iceland), Henggil volcano (SW Iceland) and a weaker swarm near Askja (N-Central Iceland) during the past 48 hours. The cause of the swarms is unclear and their intensity is not alarming. They are not necessarily volcanic, but could related to tectonic stress release around the main Icelandic rift zones. [more]
Monday, Jan 30, 2012
Friday, Oct 28, 2011
Signs of unrest beneath Katla, one of Iceland's most active volcanoes continue. A seismic swarm was recorded under the northern part of Katla volcano's caldera beneath the Mýrdalsjökull glacier in southern Iceland over the past 48 hours. 35 quakes of up to 3.2 magnitude, many at shallow depths, occrred mostly in the afternoon of 27 Oct. [more]
Tuesday, Sep 06, 2011
A mew seismic swarm is occurring at Katla volcano, with over 60 small earthquakes of magnitudes of up to 2.6 at 1-8 km depth beneath the caldera since Sunday. It could be a possibility that this swarm is caused by the injection of magma at depth, but could also be due to structural displacements. It is unclear whether the recent signs of unrest at Katla are the precursors of a new eruption in a near to medium future. [more]