Booming Dunes

The Secret of the Booming Dunes

A team of researchers constructs an experimental apparatus to explore the intonation of sand dune avalanches.

by Mason Inman • Posted July 26, 2006 @ Seed Magazine

Credit: Stéphane Douady

The bone-shakingly low bass notes that bellow during sand dune avalanches have captured the attention of explorers from Marco Polo to Darwin.

Likewise, people playing in sand dunes have found that pushing sand in different ways gives various notes: Scooting on your rump down a dune, pushing the sand downhill with your feet, triggers a low booming noise around 50 to 300 hertz (the low end of a piano scale). Pushing the sand around by hand or walking on so-called "squeaking beaches" yields higher-pitched squeals reminiscent of birds chirping or balloons rubbing together.

The causes of these sounds have eluded scientiests for more than a century.