Iceland has been evacuating its residents in the shadow of the volcanic eruption for days and is casting its watchful eyes towards the mountain Fagradalsfjall. If the eruption takes place, the Blue Lagoon resort, the Svartsenge geothermal power plant and the town of Grindavík with a population of 4,000 will also be at risk, which is why the residents of the latter have already been evacuated from their homes for the first time since 1973 (due to the lava flow of the Eldfell volcano).
The 15-kilometer volcanic magma, or dike, is a vertical fracture filled with lava, the highest point of which can be 1 km from the surface. If enough pressure develops here, the magma reaches the surface and breaks through the crust.
Dangerous past, exciting present
The population of the island is prepared for everything, caution is already in their blood, for centuries they have lived in the neighborhood of 140 volcanoes, of which 33 are still active today. Fortunately, almost 100 percent of Icelanders surf the Internet (the 2nd highest usage in the world), so information is accessible to everyone.
Its most famous volcano is the 1,491-meter-high Hekla, but there are also many geysers, the term itself got its name from the island’s Geysir, which means eruption. The Icelandic Meteorological Office is constantly monitoring the magma, the swelling of the ground is already 15-20 centimeters, the edge has solidified, which is good news, but the danger has not yet passed. Volcanologists observed that magma seeped into the cracks, swelling the volcanic cone. The sign of an eruption can be when, due to the high pressure, the gases previously dissolved in the liquid are released into the air in the form of bubbles. A change in the amount of gas and a change in the composition of the fumes, which mainly consist of water vapor, can also be warning signs that prevent an eruption.
Minor foreshocks have been keeping residents on edge for a week now, and although the number and intensity of these movements are decreasing, this does not mean that the island has escaped the eruption. Its exact location cannot be located, it is most likely to occur north of Grindavík.
As a researcher from the Institute of Earth Sciences at the University of Iceland pointed out, at the beginning of the process, a huge amount of magma was suddenly pushed towards the surface, but it has since stabilized and is filling at a constant rate. The dam is now growing and cracking, deforming the surface. If this continues, a surface eruption will be inevitable, the only question is its intensity and when.
As one expert, Jacques-Marie Bardintzeff, professor of volcanology at Paris-Saclay University, says, it could happen today or tomorrow, maybe in a few months, or never. If it does, the pressure of the gas bubbles pushes the magma toward the surface, which tears the Earth’s crust. It may flow into the town of Grindavík and destroy the houses, or it may flow north into the uninhabited countryside, or it may flow south into the sea, causing an aquatic volcanic eruption – this would perhaps be the luckiest, if we do not count the fish dying of heart attacks.
Preventive actions
The intensity of the molten rock material depends on the location of the outflow, the rate of magma emission and the duration of the eruption. The most likely scenario is that the lava erupts at high speed and then overwhelms the Blue Lagoon resort and the power plant, but in the event of an eruption in the southern part of the fissure, the town of Grindavík cannot escape either. Therefore barriers were erected and trenches were dug with a giant bulldozer to divert the lava flows. Bardintzeff called the situation in Iceland a seismic crisis.
It happened that 900 earthquakes were detected in the region in 12 hours.
A big question is whether the incident of 2010, when the eruption of the Eyjafjöll volcano paralyzed air traffic in a part of Europe, could be repeated. However, seismologists are not surprised, as the Icelandic eruption cycle has been going on for three years now. The magma definitely moves under the surface, they know all this from observing the instability of the molten rock material.
Tremors and tremors were also registered by domestic instruments
– says Erzsébet Győri, seismologist, scientific associate of the Research Institute for Earth Physics and Space Sciences. Adds:
In Iceland, the sensor network is very dense, as the level of seismicity increases, the chance of volcanic eruptions also increases.
Precision measurements
The inhabitants of the island country are therefore on alert, but despite the magma rising, disturbing the balance of the earth’s crust, and despite the frequency of seismic tremors indicating instability, these earthquakes of less than three magnitudes, which people do not even notice, do not automatically lead to eruptions. However, Iceland’s seismographs monitor volcanoes 24 hours a day. Before the eruption, the strong turbulence of the magma causes tremors, this low-frequency vibration (1-5 Hz) is also detected by the instruments.
According to Edward W. Marshall, a researcher at the University of Iceland’s Northern Center for Volcanology, if there is no eruption for three weeks, the danger is greatly reduced, as cooling begins. So there is hope.
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