An earthquake of magnitude 4.8 occurred at 3.54am this morning at the Bárðarbunga caldera in Iceland’s Highland. About a dozen aftershocks followed in its wake. The earthquake is the fourth largest in the area since the months-long Bárðarbunga eruption in 2014-2015. Experts say, however, there is no volcanic unrest in the area.
Elísabet Pálmadóttir, a geohazard specialist at the Icelandic Met Office, says it is common for Bárðarbunga to have isolated strong earthquakes like the one this morning. Such an earthquake occurred on January 5, with no follow-up activity. “We sometimes get earthquakes that are over M4, and then nothing else happens. Bárðarbunga often behaves like that.” Elísabet assures there is no sign of volcanic unrest in the area. “Nothing like it.”
Earthquake was larger than initial data suggested
The earthquake was larger than initial measurements showed. “We have an automated system that analyses earthquakes in real time and gives us a magnitude, but it was too low in relation to other data we were seeing, so it was obvious it had been much bigger. So we did the analysis again and got the magnitude 4.8, which makes it the fourth largest earthquake since the 2015 Bárðarbunga eruption. Since then there have been 12 or 13 small aftershocks, maybe around magnitude 1.”
Clear signs are likely if eruption is imminent
Magma is currently accumulating underneath the caldera, part of its regular activity. “When the eruption ended in 2015, then magma started accumulating again, in preparation for the next eruption, whenever that will be,” Elísabet explains. In 2014, seismic activity in the region gave warning of an imminent eruption around two weeks before it occurred. “Hopefully we get a clear sign beforehand like we got last time. We expect a bit of a heads up, maybe a few weeks in advance.”