Singing Dunes In Kazakhstan is the important Landscape.The Singing Dunes are in the Altyn-Emel State National Park, Kazakhstan's largest national park. The crescent-shaped sand dunes, called barchans, produce a sound described as roaring, booming, squeaking, or simply as the "Song of the Dunes." This low-pitch rumble, a natural sound phenomenon, can be as loud as 105 decibels and can last several minutes. The sound accompanies a slumping or avalanching movement of the sand, usually triggered by wind passing over the dune. Collisions between grains of sand emit surface elastic waves that, in turn, cause the motions of the grains to become synchronized. The surface of the sand acts as a loudspeaker, transmitting it through the air.