An earthquake of magnitude 4.1 was detected on the Reykjanes peninsula at 11.05pm last night. It is the largest earthquake that has been detected on the peninsula since the eruption in nearby Geldingadalir began on March 19. The earthquake is likely due to “stress movements in the earth’s crust due to the eruption,” according to the Icelandic Met Office.
For several weeks leading up to the eruption, a strong earthquake swarm originating on the Reykjanes peninsula shook South and West Iceland with quakes as strong as M5.7. The earthquakes died down as soon as magma broke the surface on March 19, indicating that a build-up of tension was being released. Last night’s earthquake was felt in the Reykjavík capital area as far away as Hella and Grundarfjörður in South and West Iceland respectively.
Eruption Shows No Signs of Stopping
It has been just over a month since the eruption began and it shows no signs of stopping. While the eruption began at one location on March 19, additional vents have since opened up along the same fissure. Lava from the eruption has filled the Reykjanes peninsula’s Geldingadalir valley completely and is now flowing into surrounding lowlands.
Though the site’s northernmost vent (which opened on Easter weekend) stopped erupting around April 18, the eruption’s lava flow has not diminished overall – in fact, it appears to have increased. “Since the eruption began about 30 days ago, it has been constantly changing,” stated Sara Barsotti, the Met Office’s Volcanic Hazards Co-ordinator. “Now there is no magma flowing out of the first crater that opened outside Geldingadalir, that for example reflects this constant change and it is not certain that the crater has gone to sleep permanently,” says Sara. “Therefore, it cannot be confirmed that these are the first signs that the eruption is subsiding. On the contrary, the latest summary of our colleagues at the University [of Iceland] shows that lava flow has not decreased and has even increased in recent days.”