High alert yesterday with evacuations, but then diminished activity

Grindavík.

Grindavík. mbl.is/Eggert Jóhannesson

Dóra Ósk Halldórsdóttir

Yesterday most specialists in volcanology thought that an eruption was pending due to the amount of magma accumulated in the magma channel, which had exceeded the amount that caused the last eruption to occur. Everything went on high alert and both Grindavík and the Blue Lagoon were evacuated. The Icelandic Met Office announced that the likelihood of an eruption was very high, and possibly within hours, if not minutes.

The Blue Lagoon.

The Blue Lagoon. mbl.is/Eggert Jóhannesson

Around 600-800 guests were in the Blue Lagoon and its hotels when the evacuation order was announced and Helga Árnadóttir, managing director of the Blue Lagoon said it took them 40 minutes to complete the evacuation once they received the order.

In Grindavík the evacuation took a little over one hour said Gunnar Schram, senior police officer in the Suðurnes Police, adding that it is not clear how many people were staying in town yesterday.

He says the next step will be the traditional closure phase that people know well, that is the closure of the three main access roads to Grindavík, Grindarvíkurvegur, Nesvegur and Suðurstrandarvegur.

"So some contractor workers are kept there, pushers and excavators, in order to have to fill in holes where roads run through the defenses, like for example Grindavíkurvegur. Otherwise it's just a standby now. Everyone knows that there is an eruption ahead, but whether it will be now or tomorrow or on Monday, it is quite difficult to say," concluded Gunnar Schram.

Seen over Grindavík to the sea.

Seen over Grindavík to the sea. mbl.is/Eggert Jóhannesson

The Coast Guard‘s helicopters were on standby due to the pending eruption, and after 4 in the afternoon, the seismic activity increased, with earthquakes in proximity to Sundhnúkagígar crater row. The plan was to fly immediately as something happened to get a clear picture of the magnitude of the eruption and what to expect.

Intense activity, but then it ceased

At 17:30 the Icelandic Met Office announced that an intense swarm of microseismic activity was occurring east of Sýlingarfell and that a fissure eruption was likely. The seismicity was moving south toward Hagafell but GPS-based measurements showed fewer signs of deformation than before previous eruptions since December 2023.

Later yesterday, the Icelandic Met Office announced that the seismicity had ceased, and it suggested that the magma intrusion had stopped temporarily. Minor deformation continued to be measured in the area, so the Met Office did not want to issue a statement yet that the magma intrusion had ended, although it did not seem like the magma would be propagating to the surface.

New magma channel

What had happened was that a new magma channel had been formed stretching between Sýlingarfell and Hagafell, which had decreased the pressure. Therefore the likelihood of a pending eruption was diminished, at least for now. However, the likelihood of another eruption is still high.

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