Lava overtakes artificial dam near the Fagradalsfjall eruption site, Iceland

Lava has overtaken the artificial dam built near the Fagradalsfjall eruption site in Iceland as of Sunday, May 23, 2021. The lava has entered the valley, leading towards the southern ring road. 

Lava has overflowed from the artificial dam that had been immediately built near Fagradalsfjall volcano in an attempt to prevent lava from entering the Natthagi Valley.

As of Sunday, lava has reached the valley, leading towards the southern ring road. As it descended the northern headwall of the valley, it produced a beautiful lava fall and formed a new flow along the bottom of the valley.

The lava is now following and covering the hiking path leading from the parking at the ring road northwards to the eruption site.

Its front is now nearing the road at 2 km (1.2 miles) away and may actually reach it if the eruption continues at its steady and gradually increasing rate.

Geological summary

The Krýsuvík-Trölladyngja volcanic system is described by the Catalogue of Icelandic Volcanoes as an approximately 50 km (31 miles) long composite fissure swarm trending about N38°E, including a 30 km (18 miles) long swarm of fissures, with no central volcano.

It is one of the volcanic systems arranged en-echelon along the Reykjanes Peninsula west of Kleifarvatn lake.

The Fagradalsfjall and Krýsuvík fissure swarms are considered splits or secondary swarms of the Krýsuvík–Trölladyngja volcanic system. 

Small shield volcanoes have produced a large portion of the erupted volume within the system.

Several eruptions have taken place since the settlement of Iceland, including the eruption of a large basaltic lava flow from the Ogmundargigar crater row around the 12th century.

The latest eruption, identified through tephrochronology, took place during the 14th century.

Featured image credit: Saul Loeb