In early November, seismologists noted a significant uptick in earthquake activity in the fishing town of Grindavik, so they began to study the Reykjanes Peninsula in southern Iceland.
Seismic activity has decreased in the last several weeks, but on December 18th, just before the magma exploded through the earth’s crust, a cacophony of seismic activity was heard. As a lengthy fissure opened and lava spurted forth, witnesses saw smoke pouring into the sky and a reddish glow in the sky. Reykjavik, the capital of Iceland, is located around 42 kilometers (26 miles) away, yet the eruption could still be seen from Grindavik, which forced the evacuation of almost 4,000 people in November.
Approximately 4,800 kilometers apart, Suzan van der Lee had a very different experience with the eruption. Sitting in her Northwester University office in Evanston, Illinois, she heard sharp cracking sounds, like a hailstorm on a tin roof, followed by an even louder crack. Earthtunes is an app that lets users listen to the crushing and grinding of our globe by converting seismic impulses that echo through it into audible sound. Van der Lee is spearheading this project.
After an intensive surge of earthquakes in early November, the activity under Reykjanes seemed to have subsided a little. Seismographic signals recorded north of Reykjavik were used to create audio snippets that sounded like ice cube splitting, someone pounding on a door, and the odd slam. Magma continued to build up at deeper depths, speeding up the pace of deformation of the terrain around Svartsengi volcano.
Lava was spewing out at a pace of hundreds of cubic meters per second from a quickly expanding fissure that tore over the terrain to the northeast of Grindavik on the 18th of December when a series of earthquakes began around 9 pm Icelandic time. On December 19th, around 3 o’clock, the fissure expanded to about 4 kilometers (2.5 miles), going southwesterly towards the outskirts of Grindavik.