High level of volcanic gases measured close to the eruption site at Fagradalsfjall, Iceland

A volcanic eruption in Geldingadalur​ near Fagradalsfjall on Iceland's Reykjanes Peninsula continues since March 19, 2021. Lava fountain activity is still low and mapping of the lava flow is in progress. While no volcanic ash has been detected, a high level of volcanic gases has been measured close to the eruption site. The public is advised to stay away from the area.

The Aviation Color Code for the Reykjanes Peninsula remains at Red, signifying an eruption in progress.

Specialists went yesterday to perform gas measurements at the eruption site. There are indications that gas emission is slightly lower than the day before, however, gas concentrations close to the lava flow were measured above the danger threshold.

SO₂ concentration close to the volcano can surpass over 9 000 µg/m³, and CO₂ can also gather in valleys in the landscape, the Icelandic Met Office (IMO) said on March 23.

The health protection limit is 350 µg/m³.

IMO is advising residents and visitors to leave the area before 17:00, keeping away from valleys and following the marked path.

Image credit: Icelandic Civil Protection and Emergency Management. Acquired March 21, 2021

The eruption fissure is about 500 – 700 m (1 640 – 2 300 feet) long.

A lot of people visited the eruption area, taking amazing images and videos but on March 22 the police closed the eruption area due to a significant increase in SO₂ gas emissions and bad weather.

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Due to the ongoing seismic activity, people are advised to avoid steep terrain as rocks and boulders can fall and chances of landslides are increased.

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 12^th century.

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

Featured image credit: Icelandic Civil Protection and Emergency Management. Acquired March 21, 2021.