After the jökulhlaup: all quiet at Katla

Following the short sharp glacial meltwater flood at Mýrdalsjökull, which was significant enough to breach the main highway, wash away a bridge and cause local evacuations, things seem to have settled down somewhat around Katla volcano. There have been no further floods and tremor under Katla has declined, although there has been a small earthquake swarm under the southern part of Katla caldera this evening (which is nothing unusual). The alert and access restrictions which were imposed by the civil protection authorities this morning have been eased except for Mýrdalsjökull itself which remains off-limits.

At the moment it is still not clear whether or not eruptive activity from Katla was responsible for the flooding, but there is certainly no evidence of eruptive products such as ash at the surface, and there has been no seismic evidence of eruption. IMO seismologist Bryndis Brandsdottir is quoted in IceNews as describing the seismicity at Katla last night as ‘small … not unusual in any way’. This morning’s glacial outburst may have very well have nothing to do with any eruptive activity at Katla at all; and if it does, it may be an isolated event; or it may be a sign that a large-scale eruption is indeed on the way. There are no signs that this is the case at the moment. Leave the last, expert, word on today’s event to volcanologist Dr Erik Klemetti: ‘When Katla does decide to not hide its eruptive activity, we are likely to expect something fairly large, in the VEI 3-5 scale. However, at this point, this is no indication that Katla is headed towards a major eruption’.

Only it’s not quite the last word in this post, because it’s time to bash the media again. Agence France Press (AFP), which did not exactly cover itself with glory in its coverage of last week’s Hekla non-event, has produced another over-excited report on the subject of Katla, in which a clear tension is discernible between the journalistic bias towards the urgent, the dramatic and the scary, and the factual and low-key comments of officials and scientists quoted. Thus while for AFP the glacial burst is a ‘massive flood of meltwater’ and a ‘giant flood’ which ‘sparked fears of an eruption at Katla’, IMO volcanologist Evgenia Ilyinskaya describes it as an entirely normal case of ‘glacial meltwater runoff from underneath the glacier’, probably produced by geothermal heating, with no evidence so far that an eruption was responsible: ‘While we can’t say for sure there was not a small subglacial eruption that caused it, we don’t see any signs of it coming up to the surface’. Having thus used expert assessments to put a lid on their own speculation about a Katla eruption, AFP blow it right off again by using our old friend overdue: ‘according to experts, the volcano, which is also located to the southeast of Grimsvoetn which was behind Iceland’s latest eruption in May, is overdue for a powerful blast’. Volcanoes, we are given to understand, run to a timetable, and this one is late.

If you’d like to see what an overdue volcano looks like, try the RÚV Katla webcam.

News
Flood video, only danger on glacier, people return home – Iceland Review, 9 July 2011
Another Iceland volcano stirs, causing flooding: official – AFP, 9 July 2011
Katla volcano in Iceland remains dormant – IceNews, 9 July 2011

Information
Global Volcanism Program: Katla – summary information for Katla (1702-03=)