Magma may start flowing into the dike underneath the town of Grindavík again days or months from now. The Icelandic town remains evacuated and experts say it is not clear when it will be safe for its residents to return to their homes. While an eruption near the town, located on the Reykjanes peninsula, is now considered less likely in the short term, a new phase of seismic activity may be beginning.
In late October, an earthquake swarm and uplift began on the Reykjanes peninsula near the town of Grindavík indicating magma collecting underground. The magma intrusion grew and filled a dike stretching beneath the town, leading authorities to issue an evacuation order on November 10 due to the risk of eruption.
A new chapter of activity
Magma inflow to the dike has likely stopped, according to a notice from the Met Office, and the chances of an eruption happening along the dike at this time have decreased. However, magma continues to accumulate just north of Grindavík, beneath Svartsengi, where a geothermal power plant and the Blue Lagoon are located. “The ongoing activity at Svartsengi, which began in October, is not yet over and a new chapter may have begun with an increased chance of a new magma propagation and, subsequently, increased likelihood of an eruption,” the Met Office notice states.
“[T]he dike beneath Grindavík was fed by magma accumulating beneath Svartsengi. It is likely that this sequence of events will repeat,” the notice continues. A new magma propagation would provide a warning in the form of earthquakes and ground deformation, which would be detected by equipment “several hours before the magma propagation is likely to pose a threat to Svartsengi or Grindavík.”
Timeline impossible to estimate
According to the Met Office, this pattern of magma accumulating beneath Svartsengi and flowing into the dike that stretches below Grindavík is likely to happen again, even repeatedly. However, it is impossible to estimate whether that will be “in the next few days or possibly after several months.”
Kristín Jónsdóttir, Head of the Volcanos, Earthquakes, and Deformation Department at the Icelandic Met Office, told RÚV it was not clear when it would be safe for Grindavík residents to return to their homes.