A volcanic fissure on Iceland’s Reykjanes peninsula reawakened in late May 2024. This eruption, the latest in a series that began in December 2023, was notable for its vigorous start. Some of the highest estimated lava flow rates of all the recent eruptions near Grindavík occurred in the first hours of the eruption.
The OLI (Operational Land Imager) on the Landsat 8 satellite captured this image of the ongoing eruption on June 2, 2024. The natural-color scene is overlaid with an infrared signal to help distinguish the lava’s heat signature. By this time, volcanic activity along a fissure extending up to 3.4 kilometers (2.1 miles) long had subsided after its initial burst. The most active areas, emitting the hottest thermal signals (light green), are near one of the craters that erupted in March 2024, according to the Icelandic Met Office (IMO). Much of the black area in the image is cooled lava, but note that dark shadows from clouds are also present.
Models indicated that 18 million cubic meters of magma had accumulated beneath the fissure since the March eruption, the IMO reported. This was the largest volume of magma to build up in the reservoir since the intrusion first formed in autumn 2023. And the lull in aboveground activity between March and May represented the longest period since late 2023 that magma had accumulated without erupting.
When lava did break through to the surface on May 29 at 12:46 p.m. local time, it gushed at an estimated 1,500 cubic meters per second for several hours. For comparison, lava discharged at an estimated 1,100-1,200 cubic meters per second in the early hours of the March eruption and 600 cubic meters per second at the start of the February eruption.
The flows again covered roads and threatened the town of Grindavík, which has largely remained empty since evacuations in late 2023. Human-built defensive walls along the northwest side of town diverted lava away from buildings. Flows also spurred renewed evacuations at the Blue Lagoon, a geothermal spa several kilometers north of Grindavík. When it reopened on June 2, visitors could see molten lava erupting in the distance.
As with previous bursts of activity, this eruption did not disrupt air travel; effusive eruptions such as these tend to emit minimal ash. However, the long daylight hours increased the likelihood for volcanic smog, or vog, to form, and this haze was observed in different parts of the country, the IMO reported. Vog, which consists primarily of very fine sulfate (SO4) particles, forms when sulfur dioxide and other volcanic pollutants mix with oxygen and water vapor in the presence of sunlight.
NASA Earth Observatory image by Lauren Dauphin, using Landsat data from the U.S. Geological Survey. Story by Lindsey Doermann.
