New eruptive fissure opens 1 km northeast of current eruption site
Mon, 5 Apr 2021, 22:1122:11 PM | BY: T
A new eruptive fissure opened today approx. 1 km northeast of the so-far active eruption site. The seismic network detected at 11:37 local time a sharp peak in tremor at 1 km depth, which announced its formation shortly after as magma broke through the surface along a new section further upslope on top of the active magma intrusion underneath.
The new eruptive fissure that opened today in Iceland (image: Almannavarnir / facebook)
According to the Icelandic Met Office (IMO), the new eruptive fissure is about 500 m long. It actually seems to consist of two close-by fractures, a larger and a smaller one, both erupting small lava fountains and feeding a new lava flow towards the east.
A few spatter cones have already been forming from lava fountaining along the fissure. Fortunately, the main RÚV webcamera zoomed on the beginning of the event at the right time as can be seen in the video below.
According to the University of Iceland, the new lava flow continues at extremely high discharge rate as a viscosity of the flow is about 10^2 Pa. The lava flow has been traveling east and continues to fill up the Meradalir valley, adjacent to Geldingadalir valley (the site of the previous phase of activity) and is about to pool into a new lava flow field.
What caused the opening of the new fissure?
There are two possibilities:
a) The rising magma flux that continues to feed the ongoing eruption was about to be blocked and likely found a new weak spot.
b) The dike was slowly closing as the magma inside was cooling and this squeezed out the remaining liquid.
The immediate area was evacuated. There was no imminent danger to life due to the site's distance form the known hiking paths.
The Aviation Color Code remains at Orange.
The ongoing eruption in Geldingadalir shows no signs of weakening and the activity has been building a slowly growing cone around the two active vents in the center.
The beginning of the new eruptive fissure:
Fri, 2 Apr 2021, 09:51
The eruption in Geldingadalir, now soon two weeks old, shows no signs of weakening. Activity has been building a slowly growing cone around the two active vents in the center, which undergoes constant modifications by accumulating spatter and smaller and larger collapses. ... Read all
Fri, 26 Mar 2021, 06:53
The eruption is now almost a week old and shows little signs of stopping anytime soon. Activity is now concentrated at two adjacent vents of a growing cone in the central part of the original eruptive fissure. They are filled with spectacularly boiling (degassing) lava that flows away to form thin flows that overlap on a growing lava field, that slowly but surely is filling the Geldingadalur valley. ... Read all