The Music of the Earth

By Joe McCool

March 17, 2003

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It's now official: The earth is a musical instrument! Seismic vibrations produced by earth quakes and volcanos are music to the ear. Professor Frank Scherbaum of the University of Potsdam's department of geophysics held an audience enthralled recently at the Institute of Civil Engineers' London HQ. He left us all in no doubt as to the earth's musical prowess.

But why is it so unusual? It is now well known that earthquakes advertise their intentions with audible sounds, quite familiar to those living in New Zealand. These are caused by the preemptive P waves, not by the main S wave of the quake itself. It's in the latter that Scherbaum's interest lies.

In the hands of a child, a tin can constitutes a musical instrument. Car bodies have been used to the same end, as have street railings. Spike Milligan has played tune across the edge of a five pound note! But like all conventional instruments, the tin can and the monetary note need an external agent, the musician, to emit the sound. The earth produces its music spontaneously and continuously, unaided.

Our reaction to "music" as distinct from mere sound or "noise" is a very clearly defined phenomenum. When we pluck a guitar string, say, we may hear the note D. But in effect this will be made up of a fundamental frequency, plus a number of supporting eigen frequencies. The eigen frequencies will be exact integer multiples of the fundamental. The spread of intensity across these affects what we call the "quality" of the sound. If discordant frequencies dominate then the result is noise, often unpleasant.

Scherbaum illustrated this using the guitar music of Brazil's Villa Lobos, composer of the "Bachianas Brasileiras". Villa Lobos made use of peculiar fingering to suppress fundamentals and enhance the harmonics. But what Frank Scherbaum has discovered is that the earth itself is capable of producing relatively high quality music, not just sound, or noise.

He had an initial inkling that this was the case, and installed microphones in Bohemia an area in his native Germany, bordering Chekoslovakia.

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