Iceland Volcano: Steady Uplift and Magma Accumulation in Svartsengi

Photo Sept. 5 of the two craters. No activity is visible. (Photo: Public Safety/Björn Oddsson)

Magma accumulation and seismic activity are being closely monitored to evaluate the potential for an upcoming event

ICELAND MET OFFICE

Updated 29. October at 18:00 UTC

• Recent assessments of magma accumulation suggest that the likelihood of a new intrusion, possibly leading to an eruption, may rise by late November
• Seismic activity remains minimal around the Sundhnúkar crater row
• The hazard assessment remains unchanged

Uplift and magma accumulation have continued steadily in Svartsengi over the past few weeks. Seismic activity around the Sundhnúkar crater row remains very low, with only a few minor earthquakes recorded each day in recent weeks.

The Icelandic Meteorological Office has evaluated how much magma must accumulate beneath Svartsengi to likely trigger the next event. Using model calculations based on GPS and satellite data, this assessment has been updated. This new evaluation suggests that the likelihood of a new magma intrusion—and possibly an eruption—increases toward late November. This estimate relies on the available deformation data. If the rate of uplift in Svartsengi changes, this assessment will be adjusted accordingly.

GPS measurements at the station SENG near Svartsengi from November 11, 2023, to present, showing shifts in the north, east, and vertical directions (top, middle, bottom). The lowest line shows uplift in millimeters, with the reading from yesterday (October 28) indicated by a green dot. Red lines mark the start of the last six eruptions (December 18, 2023; January 14, February 8, March 16, May 29, and August 22, 2024). Blue lines indicate magma intrusions that did not result in eruptions (November 10, 2023, and March 2, 2024).

Monitoring Magma Accumulation and Increasing Seismic Activity to Evaluate the Timing of the Next Event

In the weeks leading up to the past two eruptions, seismic activity in the area northwest of Grindavík increased. This activity likely indicates that pressure is rising in the magma reservoir, suggesting that the next event may be approaching.

Insights from previous intrusions and eruptions in the region facilitate an estimation of how much magma must accumulate beneath Svartsengi to trigger the next event. The timeframe during which there is an increased likelihood of a magma intrusion and possibly an eruption is framed by lower and upper uncertainty bounds. However, it's also important to monitor how and when seismic activity intensifies in conjunction with magma accumulation.

If a significant increase in seismic activity is recorded when the volume of magma beneath Svartsengi reaches the projected critical thresholds, it's expected that the likelihood of a new intrusion and potential eruption will begin to increase. This probability will gradually rise as more magma accumulates and seismic activity intensifies. It may be necessary to anticipate a heightened likelihood for an eruption for several weeks before the next event will occur.

The Icelandic Meteorological Office's hazard assessment remains unchanged from last week. The current hazard assessment is valid through November 12, unless circumstances change.

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