Early this morning, a magnitude 4.0 earthquake was detected 30 km east-southeast of Grímsey, an island off the north coast of Iceland. The quake and its aftershocks were detected in Akureyri.
Additionally, an earthquake swarm was detected at Herðubreið, in the Vatnajökull highland, the largest quakes measuring up to magnitude 3.0.
Since October 22, some 3,600 earthquakes have been registered near Herðubreið. The most powerful so far has been a magnitude 4.1, the most significant activity since measuring began near Herðubreið in 1991.
Though some several hundred kilometers apart, the Grímsey quakes, a part of the Tjörnes fracture zone, and the latest earthquake swarm near Herðubreið are a part of the same system, resting along the plate boundary in North Iceland. Herðubreið is also significant for its proximity to Askja, a major volcano system in Iceland whose 1875 eruption caused significant damage to agriculture.
Herðubreið mountain is situated within the Ódáðahraun lava field, Iceland’s largest contiguous lava field totaling 4,400 km² (1,699 mi²). Notably, Herðubreið, meaning “Broad Shoulders,” was chosen as the national mountain of Iceland in 2002. Formed by volcanic activity under a glacier, it is considered to be Iceland’s most beautiful mountain.