Grindavik is located on the Reykjanes peninsula in southwestern Iceland. In the past month, earthquakes have occurred frequently on the Reykjanes Peninsula. Although most earthquakes are relatively small in magnitude, there have also been several slightly larger earthquakes, with the largest magnitude reaching 5.2. During this swarm of earthquakes, the once prosperous Grindavik now looked like a scene from a disaster movie. Houses were damaged, roads were broken, the land collapsed, and the cracked ground was steaming upwards.
It has been half a month since the evacuation, and everyone still doesn’t know when the volcano will erupt, whether their homes will be destroyed by the lava, and when they can go home…
Magma surges and the ground bulges
A month ago, frequent earthquakes began to occur near the Fagradalsfjall volcano on the Reykjanes Peninsula. In some areas, more than 1,000 earthquakes occurred in just a few hours.
Over the next few days, seismic activity continued and some areas of the ground rose rapidly. The ongoing ground deformation is most likely caused by magma flowing into the veins. Frequent earthquakes and uplifted ground mean magma is accumulating underground.
On November 11, data from the Icelandic Meteorological Office showed that a “magma tunnel” of about 15 kilometers started from Sundhnúk in the north, extended southwest to Grindavik, and flowed into the sea. A volcanic eruption can occur anywhere along a magma tunnel. At that time, the magma was about 800 meters underground, and as a series of earthquakes, the magma continued to slowly approach the surface.
The researchers estimate that if magma continues to flow into the vein at a constant rate, it could reach the surface in the coming days or weeks. At that time, the erupted lava will soon reach the geothermal power plant, the Blue Lake and the town of Grindavik.
Currently, there is significant uplift in the ground around the geothermal power plant and the Blue Lagoon Resort. However, it is difficult to predict whether magma will definitely erupt, as well as the time, location, intensity and duration of the eruption. Researchers could only say that “the likelihood of a volcanic eruption remains high.”
The huge uncertainty has also triggered a discussion – can we drill into the rock veins under the earth’s surface, artificially divert the underground magma in advance to allow the volcano to erupt, and then control the location of the lava outflow?
In this regard, some geologists believe that this may not work because the magma in the vein is very viscous and cannot flow through the narrow opening. To allow the magma to flow through, a very large hole needs to be drilled! Moreover, the temperature of magma can reach more than 1,000 degrees Celsius, and any drilling equipment may be destroyed by the magma.
What will happen if a volcano erupts?
In 2010, Iceland’s Eyjafjallajökull volcano erupted and released large amounts of ash. Sustained northerly winds blew huge amounts of volcanic ash over the European continent, and within weeks, more than 100,000 flights were canceled. If too much volcanic ash is inhaled, the aircraft’s engines may malfunction, seriously threatening flight safety. Approximately 7 million passenger trips were affected, costing the global economy approximately US$4.7 billion.
The air quality also dropped sharply, but fortunately no one died in the eruption. The alarm system was put in place in time and residents in the area were evacuated in advance.
Scientists predict that if the volcano erupts this time, it should not cause as much damage as it did in 2010.
Because the magma beneath the Reykjanes Peninsula has a relatively low viscosity, it flows easily, allowing gas to escape and reducing the possibility of an explosion.
Moreover, this volcanic activity did not occur under the glacier, so the magma did not interact with large amounts of ice and melt water, avoiding explosive eruptions caused by instantaneous heating and vaporization.
Because of this, in Iceland, you can sometimes see some tourists stopping near erupting volcanoes to watch the red lava flows rushing on the dark surface.
In 2021, a volcano on the Reykjanes Peninsula that had been dormant for 800 years began to become active. Researchers also recorded tens of thousands of earthquakes in the weeks leading up to the eruption. In the following three years, three volcanic eruptions occurred here. All three occurred in relatively remote areas, and lava flowed into uninhabited valleys. None of them caused harm to people or disrupted air traffic.
During this time, there have been cases where magma rose in underground veins but did not eventually erupt to the surface. During its ascent, the magma may have become stuck, cooled or solidified, and ended up remaining underground. The risk of an eruption will only decrease if activity in the magma system ceases, which is not the case currently.
This volcanic activity may be the most dangerous on the Reykjanes Peninsula in years because it occurs so close to people’s living areas. Moreover, this time the dyke is larger in scale and developing faster. If an eruption occurred, some areas of the town of Grindavík would be destroyed.
If lava flows into the sea, the lava flow at about 1,000 degrees Celsius will instantly turn into steam when it encounters water, triggering an explosion and producing a large amount of volcanic ash. In addition, volcanic eruptions may also release some toxic gases.
Why are there so many volcanoes in Iceland?
In fact, the people of Iceland are no strangers to volcanic eruptions. There are about 130 volcanoes in Iceland, about 30 of which are active volcanoes, which experience volcanic activity every five years on average.
This is because Iceland sits above a volcanic hotspot. In geology, a hotspot refers to an area on the Earth’s surface where volcanic activity has been active for a long time. Hot spots, formed when hot mantle material rises from deep within the mantle to the surface of the lithosphere, are the mechanism by which the Earth releases some of its internal heat.
In addition, Iceland is located at the junction of the Eurasian and North American plates. The two plates are separated by an undersea mountain range, the Mid-Atlantic Ridge, most of which lies on the ocean floor. Iceland is the only place on the Atlantic Ridge that rises above sea level. Beneath the ridge lies the mantle plume of the Icelandic Hotspot. When the two plates separate, magma emerges from the depths and erupts on the surface.
The two tectonic plates that Iceland sits on are still pulling apart, creating ideal conditions for volcanic activity. These volcanic activities also make Iceland a country with unique and ever-changing landscapes.
In 1963, during a series of volcanic eruptions, a new island, Surtsey, emerged from the sea in southern Iceland. It is one of the youngest islands in the world, providing a valuable research base for people to understand the formation of the island, the formation and migration of animals and plants, and was selected as a World Heritage Site by UNESCO.
In addition, the magma heat in Iceland’s underground also provides Iceland with a large amount of clean energy. About 30% of the electricity comes from geothermal power generation.
No matter how the volcanic activity develops in the end, there is a high probability that this will be a very ordinary experience in Iceland’s geological history. In the face of a volcanic eruption that may occur at any time, human beings can only prepare for the worst and hope for the best.