Terrestrial Sonar

I found this thing in my desk again last night, and, as you can tell from the date in the image, below, it’s been following me around since 1998 (!). However, after seventeen years of carrying random clippings like this around in files, folders, drawers, and envelopes—after all, this is only one of many dozens—I decided it was time to get rid of it.

But not before writing a quick post.

[Image: From Scientific American, September 1998].

The original article actually appeared in Scientific American way back in their 1898 issue, making the fragment, scanned above, just a snippet published 100 years later.

The original was called “A Brazilian Indian Telephone,” and you can read it over at Archive.org. Here’s the bulk of the story:

Mr. Jose Bach, in a narrative of his travels among the Indians of the regions of the Amazon, describes in L’lllustration an instrument by means of which these people communicate with each other at a distance.

These natives live in groups of from one hundred to two hundred persons, and in dwellings called “maloccas,” which are usually situated at a distance of half a mile or a mile apart. In each malocca there is an instrument called a “cambarisa,” which consists essentially of a sort of wooden drum that is buried for half of its height in sand mixed with fragments of wood, bone, and mica, and is closed with a triple diaphragm of leather, wood, and India rubber.

When this drum is struck with a wooden mallet, the sound is transmitted to a long distance, and is distinctly heard in the other drums situated in the neighboring maloccas. It is certain that the transmission of the sound takes place through the earth, since the blows struck are scarcely audible outside of the houses in which the instruments are placed.

After the attention of the neighboring maloccas has been attracted by a call blow, a conversation may be carried on between the cambarisas designated.

According to Mr. Bach, the communication is facilitated by the nature of the ground, the drums doubtless resting upon one and the same stratum of rock, since transmission through ordinary alluvial earth could not be depended upon.

While, in and of itself, this is pretty awesome, there are at least two quick things that really captivate me here:

1) One is the simple idea that the geology of the forest itself can be instrumentalized and turned into a “telephone” network, in the most literal, etymological sense of that word (voices [-phone] at a distance [tele-]). The landscape itself becomes a percussive grid of underground communication, pounding out messages and warnings from home to home, like submarine captains pinging Morse code to one another in the deep.

It’s fascinating and, in fact, deeply strange to imagine that little rumblings or booms in the soil are actually homes corresponding to one another—and that, given the context, they might actually be talking about you.

2) The other thing is how this could be updated or, as it were, urbanized for today. You go down into the basement to get away from your family, bored of your life, trapped in a house you want to leave, wondering if you’ll ever meet true friends, and you start randomly tapping away on the sump pump, when—lo!—someone actually answers back, skittling out a little rhythm for you from another cellar just up the street. A whole suburb of feral children, drumming messages to each other in the dark, hammering on their basement floors.

It’s like those scenes in old prison flicks, where two men tap back and forth all night on their cell walls, only, here, it’s people banging on cellar floors in New York City high rises or hitting sump pumps with mallets in the wilds of suburbia, speaking back and forth through their own “Brazilian Indian Telephone,” a kind of terrestrial sonar.

(See also: using barbed-wire fences as rural telephones).


There was a short article in the August 2004 issue of The Wire about sound artist Mark Bain. “Equipped with seismometers,” The Wire writes, Bain “can turn architectural structures into giant musical instruments and demolish buildings with sound alone.” His installations have included “sensing devices, oscillators and the occasional sculptural element” – such as the “six metre high inflatable speaker” featured below.

This is the Sonusphere, formerly installed in the Edith Russ Haus, Germany. The Sonusphere musicalizes the effects of plate tectonics: “Modified seismic sensors pick up the normally unheard movements of the earth and are channeled through the entire building until reaching a ‘crescendo’ in Bain’s sonusphere. Unique in its purpose and design, the sonusphere is essentially a wired, inflatable ball that fills the entire upper floor and takes signals generated from an acoustic network running through the entire architecture. It acts as a low frequency, 360 degree, acoustic radiator translating the sound to its curved walls as physically pulsating sound pressure.”
Bain’s work, The Wire explains, references “the ideas of maverick engineer Nikola Tesla.” Tesla’s prolific output and avant-garde electrical ideas inspired Bain to develop “a system for resonating buildings that allowed him to ‘play’ structures. ‘The multi-resonator system I designed could drive waveforms into buildings,’ Bain comments, ‘like giant additive synthesis where you get different beatings of frequencies and shifted harmonics. I was basically designing systems that turned a structure into a musical instrument.'”
Elsewhere, we’re told, “the portable earthquake machines [that Bain] showed in Holland in 2001 produced severe tremors that spread through the surrounding area. Then there was Het Paard, a large music venue in The Hague slated for demolition. The oscillators he attached to the building activated the entire structure, inflicting severe damage on parts of the walls and ceilings.”
Of course, Bain has been on BLDGBLOG before, where we discuss a musical composition of his made entirely from seismic data recorded during the collapse of the World Trade Center on 9/11 – the trembling of Manhattan turned into a roar of sound. (Listen to an excerpt here).

(Similar ideas are taken up in this post).

Sound dunes

“Sand dunes in certain parts of the world are notorious for the noises they make,” New Scientist reports, “as sand avalanches down their sides. Some [dunes] emit low powerful booms, others sound like drum rolls or galloping horses, and some are even tuneful. These dune songs have been reported to last for up to 15 minutes and can sound as loud as a low-flying airplane.”

To test for the causes, properties, and other effects of these sand dune booms, “Stéphane Douady of the French national research agency CNRS and his colleagues shipped sand from Moroccan singing dunes back to his lab to investigate.” There, Douady’s team “found that they could play notes by pushing the sand by hand, or with a metal handle.”

The transformation of a sand dune – and, by extension, the entire Sahara desert, indeed any desert – even, by extension, the rust deserts of Mars – into a musical instrument. Music of the spheres, indeed.

“When the sand avalanches, the grains jostle each other at different frequencies, setting up standing waves in the cascading layer, says Douady. These waves reinforce one another, making the layer vibrate like the surface of a loud speaker. ‘What’s funny is that in these massive dunes, only a thin layer of 2 or 3 centimetres is needed to set up the resonance,’ says Douady. ‘Soon all grains begin to vibrate in step.'”

Douady has so perfected his technique of dune resonance that he has now “successfully predicted the notes emitted by dunes in Morocco, Chile and the US simply by measuring the size of the grains they contain.” The music of the dunes, in other words, was determined entirely by the size, shape, and roughness of the sand grains involved, where excessive smoothness dampened the dunes’ sound.

I’m reminded of the coast of Inishowen, a peninsula south of Malin Head in the north of Ireland, where the rocks endlessly grind across one another in the backwash of heaving, metallic, grey Atlantic waves. Under constant pressure of the oceanic, the rocks carve into themselves and each other, chipping down over decades into perfectly polished and rounded spheres, columns, and eggs – as if Archimedean solids or the nested orbits of Kepler could be discovered on the Irish ocean foreshore –

– all glittering. The rocks, I later learned, were actually semi-precious stones, and I had a kind of weird epiphany, standing there above the hush and clatter of bejewelled rocks, rubbing and rubbed one to the other in the depopulated void of a coastal November. It was not a sound easy to forget.

Because the earth itself is already a musical instrument: there is “a deep, low-frequency rumble that is present in the ground even when there are no earthquakes happening. Dubbed the ‘Earth’s hum‘, the signal had gone unnoticed in previous studies because it looked like noise in the data.”

Elsewhere: “Competing with the natural emissions from stars and other celestial objects, our Earth sings like a canary – it drones on in a constant hum of a gazillion notes. If it were several octaves higher, and hence, audible to the human ear,” it could probably get recorded by the unpredictably omnidirectional antennas of ShortWaveMusic and… you could download the sound of the earth. Free Radio Interterrestrial. [Note: the “drones on” link, a sentence or two back, offers a contrary theory (published in 2000) about the origins of these planetary sound waves.]

Which, finally, brings us to Ernst Chladni and his Chladni figures, or: architectonic structures appearing in sand due to patterns of acoustic resonance. The architecture of sand, involving sound—or architecture through sound, involving sand. Silicon assuming structure, humming.

The gist of Chladni’s experiments involved spreading a thin layer of sand across a vibrating plate, changing the frequency at which the plate vibrated, and then watching the sand as it shivered round, forming regular, highly geometric patterns. Those patterns depended upon, and were formed in response to, whatever vibration frequency it was that Chladni chose.

So you’ve got sand, dune music, terrestrial vibration, some Chladni figures – one could be excused for wondering whether the earth, apparently a kind of carbon-ironic bell made of continental plates and oceanic resonators, is really a vast Chladni plate, vibrating every little mineral, every pebble, every grain of sand, perhaps every organic molecule, into complex, three-dimensional, time-persistent patterns for which we have no standard or even technique of measurement. Or maybe William Blake knew how to do it, or Pythagoras, or perhaps even Nikola Tesla, but…

The sound dunes continue to boom and shiver. The deserts roar. The continents hum.