Tracking the sounds buried in sand dunes.

• Position: Death Valley - Brief article

In the dark hours of early morning, before the scorching heat arrives, Melany Hunt, professor of mechanical engineering at the California Institute of Technology, Pasadena, and her research team climb massive sand dunes in the Mojave Desert's Death Valley.

With heavy equipment in tow, they listen for sounds beneath the billions of granules--an acoustic stirring that has been noted for centuries. The team investigated the characteristics of waves emitted during what are known as burping and booming emissions. Their findings are detailed in Physics of Fluids.

Booming sand dunes produce a persistent, low-frequency sound that resembles a pure note from a musical instrument. Prior to the onset of booming, the emission...