Similar tremors have been observed ahead of volcanic eruptions in the past, and the Icelandic Meteorological Office said that magma movements were a likely cause for the continuing activity. The agency has warned that an eruption could occur within days or weeks.
“The two tectonic plates are moving away from each other, and that movement has created the conditions for magma to come to the surface,” said Freysteinn Sigmundsson, a research professor of geophysics at the University of Iceland.
Dr. Einarsson said that out of the five volcanoes in the Reykjanes area, magma movement had been observed near at least three of them since the seismic episode began in December 2019. “We may be entering a new active period in the peninsula,” he added. “There seems to be food for some eruption.”
Iceland has about 30 active volcanoes, but volcanologists say an eruption in Reykjanes won’t threaten inhabited areas on the peninsula. “We’re talking about an effusive eruption, rather than explosive,” said Dr. Sigmundsson, explaining that the lava would likely bubble out with little explosive force.
He added that any activity is unlikely to be as disruptive as the eruption that occurred in 2010, when another volcano in Iceland released a plume of ash so vast that it caused one of the most significant air-traffic interruptions in decades, stranding millions of passengers in Europe, some for weeks.
The meteorological office said the volcanic activity could occur near Fagradalsfjall, 20 miles south of Reykjavik, or near the Keilir mountain close by. Hundreds of volcano enthusiasts have been riveted to live cameras in the area, and a website asking “Has there been an eruption yet?” has kept them up-to-date. (It still read “Nei” — No — as of Thursday afternoon, but a playlist on the website helped with the wait.)
The meteorological office said that among possible scenarios, the ongoing seismic activities could decrease in the coming days or weeks, but the peninsula could also face more earthquakes, up to magnitude 6.5.