The Icelandic authorities declared on Monday night the level of Civil Defense emergency in the country, after a volcanic eruption occurred on the Reykjanes peninsula, just 3 kilometers from the fishing town of Grindavík, whose more than 3,500 inhabitants have been evacuated since November. . The entire region is currently closed to traffic.
The eruption has come after two months of tremors in the area. Although seismic activity had been significantly reduced in recent days, scientists from the Icelandic Meteorological Organization (IMO) noticed an uptick in both the quantity and intensity of earthquakes an hour before the start of the event. This is the fourth eruption in four years in the area.
“Now we wait to see what the forces of nature have in store for us. We are prepared and remain vigilant,” the president of Iceland, Gudni Johannesson, has published on his X account, formerly Twitter.
The event began at 10:17 p.m. local time on Monday night (11:17 p.m. Spanish time). It is a fissure eruption, typical Icelandic, low explosive and producing little ash. The fissure, located northeast of Grindavík, has a length of about 4 kilometers, longer than in previous eruptions, according to the IMO, and has expelled between 100 and 200 cubic meters of lava per second during the first hours.
The intensity of the eruption, which generated lava fountains tens of meters high, has subsequently reduced, something typical of recent events on the Reykjanes Peninsula, and which should not be interpreted as a sign that the event is coming. to its end. The lower seismic activity and ground deformation simply indicate that “the eruption is reaching a state of equilibrium,” says the IMO.
The Ministry of Foreign Affairs has assured in a statement that the eruption “does not present a mortal threat”, and has ruled out the possibility of canceling flights, both international and local. The southern end of the fissure, the closest to Grindavík, is about three kilometers from the town, and authorities are assessing the risk of the magma affecting infrastructure, including the Svartsengi geothermal power plant. , and the Blue Lagoon spa, closed to the public.
In the absence of an official assessment, “the eruption is taking place to the north of the basin, so the lava does not flow towards Grindavík,” geologist Bjorn Oddson told RUV, local public television. That is to say, according to the expert, the profile of the eruption area separates the lava from the fishing town. However, by night the fissure was expanding southward, according to the IMO.
“The greatest dangers of this eruption could be the lava flows that can affect infrastructure, buildings and houses, as well as the emission of SO2 that, depending on the winds, can affect other inhabited areas,” explains Itahiza Domínguez, seismologist. of the National Geographic Institute (IGN), in statements to Science Media Center. The expert details, however, that it is still too early to make such an evaluation. “It is not an eruption that is going to generate large amounts of ash,” he concludes.
There was a possibility that the lava would come out directly through a fissure within the town of Grindavík, something that has been avoided for now. The other main concern of the authorities was that the eruption would occur in the sea, in a shallow area. If this had been the case, this would have favored the formation of a very high ash column, which could have disrupted air traffic.
There is no exact forecast for how long the eruption may last. The event will most likely last from weeks to months, which is most common, according to the IMO, in effusive volcanoes like the current one. In the case of Fagradalsfjall, the volcanic system that has led to the latest Icelandic eruptions, also located on the Reykjanes peninsula, no event has lasted more than half a year.
Iceland has 34 volcanic systems that have been active during the Holocene, in the last 11,500 years, according to the official catalog of the IMO, the University of Iceland and the Civil Protection Department of the local police. “It is a completely volcanic island, it is all volcanoes,” says Rubén López, volcanologist at the National Geographic Institute (IGN), in conversation with La Vanguardia. In the last 50 years, more than 20 eruptions have occurred in the country.
The country is located in an area that combines two particularities that make it especially predisposed to volcanism, according to the British Met Office. On the one hand, it is located on the Mid-Atlantic Ridge, an area in which the Eurasian and North American tectonic plates separate a few centimeters each year. This separation causes fissures, that is, the rupture of the Earth’s crust, through which magma rises, producing volcanic eruptions.
In addition, it is believed that the island is above a mantle plume, an area in which the magma has a higher temperature than usual. So much so that it melts and thins the Earth’s crust. This leads to higher volcanism, which would help explain the frequency of eruptions in the country.
The island combines special geological and climatological conditions, which make it have an unusual volcanic diversity, as stated in a summary article from 2004. Virtually all types of volcanoes and eruptions known on Earth have been recorded. Iceland is home to polygenetic volcanoes, formed over many eruptions, and monogenetic ones, the result of a single event. There are flatter and more vertical ones, formed by the accumulation of lava and layers of ash, and which appear on the ground of the island, but also under water (underwater) and under frozen areas (subglacial).
In Iceland there are effusive eruptions – in which lava is basically emitted -, explosive eruptions – in which tephra, solidified fragments of magma are mainly produced – and a mixture of both. And, throughout history, there have been very intense ones and weaker ones.
“The volcanic origin is very different,” describes the IGN volcanologist. “Iceland is in a ridge, an area where the plates separate and magma shoots upward, while the Canary Islands is an area called a hot spot, and magmatic intrusions come from there,” he continues. Furthermore, “in Iceland there are many fissures with eruptions with very little gas, which is why the Icelandic eruptions are very low intensity”, while the Canary Islands, such as the one in La Palma, tend to be more explosive. “The lava is similar, it is a very basaltic lava, very black,” he concludes.
The variable that provides information about the magnitude of an eruption is the explosive activity index. “It is measured by several factors, such as the ash column, the duration of the volcano, the magma that is ejected…” says López. From there “a fairly complex analysis is carried out, sometimes quite subjective, and it is valued from 0 to 8 on an exponential scale.” The expert describes that the eruptions seen in recent years in Iceland tend to be monogenetic, with low explosive activity rates.