Iceland’s geology is particularly moody at the moment. As Fagradalsfjall volcano gears up for its impending eruption, hundreds of earthquakes are rocking the island’s Reykjanes Peninsula each day. Thanks to Northwestern University’s Earthtunes app, it’s possible to hear the creaking and clattering of deep seismic forces currently working beneath the island.
The latest collection of sounds were recorded last week in early November 2023 by the Global Seismographic Network station (named BORG), located to the north-northeast of the capital Reykjavík.
This seismic activity can’t usually be heard with human ears, but the researchers transform the seismic frequencies into audible pitches. It’s effectively translating the squiggly lines of a seismometer into sonic data.
“What you’re hearing is 24 hours of seismic data — filled with earthquake signals. The vast majority of these quakes are associated with the magma intrusion into the crust of the Fagradallsfjall-Svartsengi-Grindavik area of the Reykjanes Peninsula," Suzan van der Lee, a seismologist at Northwestern University who co-developed Earthtunes, said in a statement.
"Seismic data are not audible; their frequencies are too low. So, the 24 hours of data are compressed into approximately 1.5 minutes of audio data. You can hear an unprecedented intensity of earthquakes during the night from last Friday into Saturday and related to a new magma intrusion into the crust area,” she added.
Iceland is bustling with volcanic and seismic activity because it’s situated on the Mid-Atlantic Ridge, where the North American and Eurasian plates are pulling apart, allowing magma to rise from the mantle. It’s also located on top of a hotspot (that’s the actual scientific term) where magma is especially close to the surface.
Things are particularly hot-tempered at the moment. On November 12, there were 1,000 quakes in Reykjanes Peninsula and many suspect that a volcanic eruption of Fagradalsfjall is imminent. The risk is so high that Icelandic authorities excavated the fishing town of Grindavík after giant cracks formed along its roads.
“The activity is formidable, exciting, and scary,” van der Lee remarked.
After centuries of quiet, eruptions on the Reykjanes Peninsula started again in 2021, ushering in a new era of intense seismic activity. It seems likely that Iceland's southwestern peninsula is now facing decades of volcanic instability ahead.
“This level of danger is unprecedented for this area of Iceland, but not for Iceland as a whole. While most Icelandic volcanoes erupt away from towns and other infrastructure, Icelanders share the terrible memory of an eruption 50 years ago on the island Vestmannaeyjar, during which lava covered part of that island's town, Heimaey,” van der Lee explained.
“The residents felt very vulnerable, as the evacuated people of Grindavík feel now. In a few days or weeks, they might no longer have their jobs, homes, and most possessions, while still having to feed their families and pay their mortgages. However, partially resulting from that eruption on Vestmannaeyjar, Icelanders are well prepared for the current situation in the Fagradallsfjall-Svartsengi-Grindavík area,” she added.