We often think of volcanoes as skyscraping marvels, but these portals to the geologic underworld also reside underwater. Unfortunately, submarine volcanoes are trickier to study than their terrestrial siblings. But you would be hard-pressed to find anyone more enchanted by them — and more stubbornly determined to study them — than Jackie Caplan-Auerbach.

A volcanologist at Western Washington University, Caplan-Auerbach is also a seismologist, someone who uses the jiggles of earthquakes to understand geophysics. And it just so happens that active volcanoes are prodigious earthquake producers; they make as much seismic noise as they can muster. For Caplan-Auerbach, that noise is music to her scientific ears — data that can be used to learn about the internal workings of our planet.

Listening to these volcanic songs isn’t just about satiating an isolated scientific curiosity. When a submarine volcano in the South Pacific named Hunga Tonga-Hunga Ha‘apai catastrophically exploded in January 2022, it produced a devastating regional tsunami, caused the atmosphere to thrum like the surface of a drum, and buried the Kingdom of Tonga’s main island in ash. Caplan-Auerbach and her colleagues hope that by studying the soundtrack of such violent eruptions, they can learn enough about the physics behind the paroxysms to ease the impacts of future volcanic disasters.

Quanta Magazine caught up with Caplan-Auerbach to discuss her journey into geophysics and what it’s like to study the melodies of these magmatic mountains. The interview has been condensed and edited for clarity.

How do you describe what you do?

I study the earthquakes that take place in volcanic systems, which I describe as the songs of the volcano. I’ve always loved sound. And I’ve always loved resonance and standing waves. A classic example of standing waves is when you take a beer and blow over the top of the bottle, and it hums — or it’s when you run your finger on the top of your wineglass, which is more to my boozy tastes, and the glass sings. Everything has a hum that is associated with its shape and its material properties, and volcanoes are no different. Their conduits have hums.

I don’t know why, but that science has always really appealed to me. That was exactly the thing that I loved, and I get to do it on volcanoes.