Intensifying seismic activity these past few weeks along Iceland's southwestern Reykjanes Peninsula—marked by tens of thousands of earthquakes, as many as 1,400 within one 24-hour period—has experts warning of a likely volcanic eruption at any time. While such activity is typically monitored by seismometers, seismologists at Northwestern University are also listening to the data collected by the region's Global Seismographic Network station using an app they developed a few years ago called Earthtunes.
With the app, those earthquakes can sound like slamming doors or hail pelting a window or roof. “The activity is formidable, exciting, and scary,” said Suzan van der Lee, a Northwestern seismologist who co-developed Earthtunes. “Iceland did the right thing by evacuating residents in nearby Grindavik and the nearby Svartsengi geothermal power plant.”
Sonification of scientific data is an area of growing interest in many different fields. For instance, several years ago, a project called LHCSound built a library of the “sounds” of a top quark jet and the Higgs boson, among others. The project hoped to develop sonification as a technique for analyzing the data from particle collisions so that physicists could “detect” subatomic particles by ear. Other scientists have mapped the molecular structure of proteins in spider silk threads onto musical theory to produce the "sound" of silk in hopes of establishing a radical new way to create designer proteins. And there's a free app for Android called the Amino Acid Synthesizer that enables users to create their own protein "compositions" from the sounds of amino acids.
Scientists have sonified a black hole's X-ray echo, in which lower-frequency light corresponds to a lower-pitched sound. Others have turned the sounds of a Martian sunrise (the data was collected by the Mars Opportunity rover) into music and also have composed music based on particle physics data used to discover the Higgs boson, as well as on magnetometer readings from the Voyager mission. And, back in August, astronomers converted data on stars' innate "twinkle"—produced by how gases ripple in waves across their surface—into audible sounds, playing "Twinkle, Twinkle, Little Star" and Gustav Holst's "Jupiter" in the "language" of the stars. So it's not surprising that seismologists have also turned to sonification.
Iceland straddles two tectonic plates, which are divided by an undersea mountain chain that is oozing magma, and when that magma pushes through the plates, earthquakes occur. The Reykjane Peninsula is particularly known for its active volcanism, with a landscape featuring little vegetation and large fields of lava. The local hot springs are a popular tourist attraction, most notably the luxury spa near the geothermal power station known as the "Blue Lagoon." Despite the active nature of its volcanoes, the region has been relatively quiet for nearly 800 years, per geological records, but that changed with the March 2021 eruption of the Fagradalsfjall volcano. It was a small eruption, but many experts believed this event heralded the start of a new period of volcanic activity that could last centuries.
Earthtunes audio of 24 hours of seismic activity recorded from November 10-11.
The recent sharp increase in seismic activity along the peninsula has reinforced those predictions. "It looks like 2021 kicked off a new eruptive phase which might see the several fault zones crossing the [peninsula] firing on and off for centuries," University of Cambridge volcanologist Clive Oppenheimer told Live Science.
The Icelandic Met Office (IMO) has been closely monitoring the seismic activity around the clock. Last Friday, they realized that magma was running into the ground underneath Grindavik and fracturing rock over a distance of nine miles (15 kilometers), cracking roads, damaging homes, and forcing evacuations. The entire town has sunk over three feet (more than one meter) since then, according to BBC News, and is still sinking about 1.6 inches (four centimeters) each day. The anticipated eruption is expected to be low-intensity but still quite dangerous, with lava running from various fissures over the course of several weeks.
“This level of danger is unprecedented for this area of Iceland, but not for Iceland as a whole,” said van der Lee. “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. The residents felt very vulnerable, as the evacuated people of Grindavik feel now. However, partially resulting from that eruption on Vestmannaeyjar, Icelanders are well prepared for the current situation in the Fagradallsfjall-Svartsengi-Grindavik area.”