What does seismic activity actually sound like. One descriptor is “formidable, exciting and scary.” New advances in audio recording enable scientists, and the general public, to listen in and hear sounds that were previously inaudible.
Audio clips from the end of December 2023, presenting the unprecedented intensity of earthquakes across the Reykjanes Peninsula are available. These sounds are also described as being similar to slamming doors and hail violently pelting a tin roof. These were recorded ahead of an expected eruption of a fissure near Iceland’s Fagradalsfjall volcano.
Seismologist Suzan van der Lee co-developed the Earthtunes app. Van der Lee is the Sarah Rebecca Roland Professor of Earth and Planetary Sciences at Northwestern University’s Weinberg College of Arts and Sciences.
The app transforms seismic frequencies into audible pitches. Whereas a classic seismometer records motions in the Earth’s surface as squiggly lines scratched across a page, Earthtunes enables users to hear, rather than see, activity.
The recordings were made at the Global Seismographic Network station (BORG), located to the north-northeast of Reykjavik. The audio presents recorded data with the pitch increased by 10 octaves. Listeners can hear a long, low rumbling sound, punctuated by an occasional sharper bang.
Van der Lee achieved these unusual recording by applying data science to millions of records of seismic waves in order to decode seismic signals. The scientific interest in this is to harness valuable information about the Earth’s interior dynamics.
This reflects the thermal boundary layers (across which the temperature varies continuously) where buoyancy causes instabilities, allowing fluid to leave the boundary layer and rise or fall throughout the system interior, triggering seismic events.
Listen for yourself
Recordings of the eruption of the svartsengi-grindavik fissure in Iceland, can be heard via the Northwestern University’s Earthtunes app. Here you can be immersed in a cacophony of sharp knocking noises. With the recording, 24 hours of data are compressed into approximately 1.5 minutes of audio data.
Tuning in, it is possible to hear noises intensify around the time the eruption begins. As the fissure becomes fully formed, the sounds become quieter. During this quieter period, the Earth’s crust is no longer fracturing, allowing magma to flow freely.
