CW: references to death, religion 

The year is 1783, and it seems that the end is nigh – at least, that is the impression of Icelandic priest Jón Steingrímsson. His diary offers a striking firsthand account of a fissure eruption which would last around eight months and claim the lives of approximately 9,000 people. These events are characterised by the emergence of molten magma through a crack in the Earth’s crust; and though they might lack the dramatic, Vesuvian spectacle of a typical volcanic eruption, they can be no less devastating (Witt et al., 2018).

Steingrímsson recounts how “the ground swelled up with tremendous howling” before “flames and fire erupted” and sent “great blocks of rock and pieces of grass…high into the air”. There could only be one explanation for such apocalyptic scenes: these were surely “the signs of an angry god” (Bressan, 2013). In a last-ditch effort to save the local populace from this act of divine wrath, Steingrímsson held a church service in the town of Kirkjubæjarklaustur – which the relentless magma threatened to engulf – in which he urged repentance and led feverish prayers for mercy. It has gone down in Icelandic folklore as the Eldmessa, or ‘fire mass’ (Andrews, 2018).

Since October 2023, Iceland’s Reykjanes Peninsula has been beset with an intense new wave of seismic activity and fissure eruptions (Andrews, 2024). In these ‘rift zones,’ magma can seep upwards through splits in the Earth’s crust towards the surface, forming large dikes and potentially creating multiple vents from which lava fountains can occur (Witt et al., 2018). At the time of writing, the situation has been declared stable by the Icelandic Met Office. But after centuries of dormancy, it has made the extraordinary power residing beneath the surface of our planet abundantly clear to local and international observers alike. It might seem that people are helpless in the face of such raw, elemental forces; all we can do is hope and pray. Yet, thanks to the tireless work of local authorities and dedicated scientists, it has become possible to decode the previously ineffable language of the fiery interior – and save lives in the process (Andrews, 2024).

At the heart of this effort lies the Interferometric Synthetic Aperture Radar (InSAR), which enables scientists to map surface deformations and, hence, to infer magma movements (Tolpekin, 2023). This imaging technique records the backscatter of microwave signals as they ‘bounce’ off the surface (European Space Agency, n.d.). When two images are taken of the same location at different times – and then aligned pixel by pixel – the level of deformation can be represented with an interferogram, which functions like a brightly coloured topographic map (NASA, n.d.). 

This technology has major implications for planning authorities (Ducrocq et al., 2024). The increased frequency and intensity of tremors that began late last year, for instance, heralded the possibility of an imminent eruption. In conjunction with Iceland’s network of over 50 seismographs – ground-based devices which detect movement in all directions – InSAR provided the early warning on November 10 (Icelandic Met Office, n.d.). Beyond measuring the deformation magnitude (around 50 centimetres), scans also showed the localised area that was most likely to be affected, around the town of Grindavik. A state of emergency was declared by the Icelandic government on November 12, and the town was subsequently evacuated. The Reykjanes fissure first erupted in December and has done so three more times since then, as of 19th March 2024 (Baker, 2024). 

Having lain dormant for centuries, the peninsula could now face decades, even centuries, of heightened volcanic activity (Andrews, 2024). Situated on the ridge between the North American and Eurasian tectonic plates, Iceland has long been a hotbed for geologists and other scientists; the most recent eruptions will continue to foster a deeper knowledge of the primordial forces at work beneath the crust. Even technology such as InSAR cannot flawlessly predict where the next fissure will occur, with the systems at work simply too complex and subject to unpredictable changes, nor does it offer the opportunity to tame these forces. But forewarned is forearmed: the lives that have already been saved illuminate the role of scientific understanding as a force for overcoming our powerlessness in the face of the elements. The fury of heaven, as Steingrímsson would surely have it.

References

Andrews, R.G. (2024, February 20). Inside Scientists’ Life-Saving Prediction of the Iceland Eruption. Quanta Magazine. https://www.quantamagazine.org/inside-scientists-life-saving-prediction-of-the-iceland-eruption-20240220/

Andrews, R.G. (2018, April 4). The Legend of The Icelandic Pastor Who Appeared To Stop A Lava Flow. Forbes. https://www.forbes.com/sites/robinandrews/2018/04/24/the-legend-of-the-icelandic-pastor-who-appeared-to-stop-a-lava-flow/?sh=703ae4301798

Baker, H. (2024, March 19). Iceland volcano: 'Most powerful' eruption yet narrowly misses Grindavik but could still trigger life-threatening toxic gas plume. Live Science. https://www.livescience.com/planet-earth/volcanos/iceland-volcano-most-powerful-eruption-yet-narrowly-misses-grindavik-but-could-still-trigger-life-threatening-toxic-gas-plume

Bressan, D. (2013, June 8). June 8, 1783: How the “Laki-eruptions” changed History. Scientific American. https://www.scientificamerican.com/blog/history-of-geology/8-june-1783-how-the-laki-eruptions-changed-history/

Ducrocq, C., Arnadottir, T., Einarsson, P., Jonsson, s., Drouin, V., Geirsson, H., & Hjartadottir, A.R. (2024). Widespread fracture movements during a volcano-tectonic unrest: the Reykjanes Peninsula, Iceland, from 2019-2021 TerraSAR-X intereferometry. Bulletin of Volcanology, 86 (14). https://doi.org/10.1007/s00445-023-01699-0

European Space Agency (n.d.). How does interferometry work?https://www.esa.int/Applications/Observing_the_Earth/How_does_interferometry_work

Icelandic Met Office (n.d.). 100 Years of Seismic Observations. https://en.vedur.is/earthquakes-and-volcanism/conferences/jsr-2009/100_years/

NASA (n.d.). Interferometry. https://nisar.jpl.nasa.gov/mission/get-to-know-sar/interferometry/#:~:text=Interferometry%20is%20an%20imaging%20technique,reveal%20surface%20motion%20and%20change.

Tolpekin, V. (2023, November 17). ICEYE Interferometric Analysis: Monitoring Potential Volcanic Eruption in Iceland. ICEYE. https://www.iceye.com/blog/iceye-interferometric-analysis-monitoring-potential-volcanic-eruption-in-iceland  

Witt, T., Walter, R.T., Muller, D., Gudmundsson, M.T., & Schopa, A. (2018). The relationship between lava fountaing and vent morphology for the 2014-2015 Holuhraun eruption, Iceland, analysed by video monitoring and topographic mapping. Frontiers in Earth Science, 6. https://doi.org/10.3389/feart.2018.00235