When the Fagradalsfjall volcano in Iceland began to erupt in 2021, experts banded together to create defensive barriers with dirt to protect civilians in the surrounding areas. 

Crews from the Icelandic Department of Civil Protection and Emergency Management worked around the clock to build barriers to curtail the lava flow. A field study, led by Norwegian University of Science and Technology (NTNU) Professor Fjola Gudrun Sigtryggsdottir, analyzed how effective these prevention methods were and if they could be used in the future. 

“The main lesson we learned from that field experiment was that it is possible to control lava flows – to some extent. And it is certainly worth trying when it comes to protecting civil society and critical infrastructure,” said Sigtryggsdottir in a press release. 

A Field Study on an Active Volcano 

The Fagradalsfjall volcano hadn’t erupted in almost 800 years. However, that all recently changed as the volcano began showing signs of seismic activity, and eventually erupted in March of 2021. 

To protect civilian life and the infrastructure, construction crews used bulldozers and excavators to build earthen barriers and rock dams. During this time, Sigtryggsdottir’s conducted a field study to measure the barrier’s effectiveness. 

According to the study, published in Bulletin of Volcanology, during an eruption that may impact civilian life, delaying lava flow and preserving time is the ultimate goal. In this case, the study found the crews delayed the lava flow for 16 days. The barriers and dams also diverted the lava flow towards a safe direction. 

Read More: How to Stay Safe Before, During, and After a Volcano Eruption

Building Volcanic Protection 

Before the eruption occurred, the Icelandic Department of Civil Protection and Emergency Management (DCPEM) was already discussing mitigation plans. Before the Fagradalsfjall volcano erupted, the area was already experiencing seismic activity, including 40,000 earthquakes. 

Officials from the DCPEM, along with Sigtryggsdottir, researchers from the University of Iceland and the Icelandic Meteorological Office, and engineers from Verkis and Efla consulting firms, mapped out areas that lava flows could impact and brainstormed protection methods to keep the region safe. 

The volcano continued to erupt for several months, but slowed in September 2021. From there, researchers tested different methods, including temporary versus long-term measures.

In total, the crews constructed three embankment dams made of dirt and stone, the highest of which was about 26 feet tall. The crew also built two 1100-foot-long barriers that helped divert the lava flow in a different direction.   

Protecting the Future

The information gained from this field study would prove useful as the volcano began to erupt again at the end of 2023. Officials, using a guide put together by Sigtryggsdottir, put proper protections in place and protected Grindavík along with a geothermal power plant outside of the town. 

Without these protections, lava may have impacted the town. 

“If the barriers had not been built, several of the houses there would now be under lava,” Sigtryggsdottir said in a press release.

However, the landscape around the volcano continues to change. Recently, a new fissure has opened near Grindavík. Though the eruption didn’t last long, nothing was destroyed. In the meantime, monitoring is still taking place as things shift, but there are now better safety measures in place. 

“Although there’s a lot of uncertainty regarding the development of the eruption itself, it is fully possible to delay and divert lava flows. There are many challenges, but civil society and infrastructure can be protected, and when we can, we must seize the opportunity and believe it will work,” Sigtryggsdottir said in a press release.

Read More: Volcanic Eruption Warnings Are Now Possible With Fiber-Optic Cables

Article Sources

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A graduate of UW-Whitewater, Monica Cull wrote for several organizations, including one that focused on bees and the natural world, before coming to Discover Magazine. Her current work also appears on her travel blog and Common State Magazine. Her love of science came from watching PBS shows as a kid with her mom and spending too much time binging Doctor Who.