Singing Sand Dunes

Various Theories – Singing Sand Dunes

There are various theories regarding the singing sand dunes mechanism and it has been suggested that these sound frequency has been controlled by the cut off rate. Others indicate that the frequency of vibrations could be connected to the thickness of the dry surface layer of the sand.

The sound waves tend to bounce back and forth between the surface of the dunes and the surface of the moist layer. This gives rise to resonance which increases the volume of the sound. The sound could be generated by friction between the grains or it could be due to the compression of air between them. Some other sounds which are produced by sand have been described as roaring or booming.

Certain note which is produced between 60 and 105 hertz by the dune has been controlled by the rate of collision in the cut off band splitting the avalanche from the static area of the dune. For impulsive avalanche, frequency tends to be controlled by gravity as well as by the size of the sand grains and the entire length of the landform is around 185 km.

Sound – Roaring/Squeaking/Song of Dunes

Some sand dunes tend to make strange low frequency humming noise which may sound like a drone of a distant propeller aircraft. This sound could be quite loud and in some incidents, it could be heard from a distance of several kilometres.

Singing sand dunes an example of the phenomenon of singing sand, tends to produce sound which has been described as roaring, squeaking or the `Song of Dunes’. This is a natural occurrence of around 105 decibels which tend to last for several minutes.

It occurs in about 35 desert locations all over the world. It is said that the sound seems similar to a loud, low pitch, rumble and originates from the crescent shaped dunes or barchans. The sound which is produced is accompanied with a slumping or avalanching movement of the sand, generally activated by the wind passing over the dune or by someone probably walking near the crest.

Unusual/Eerie

The sound could be somewhat unusual and eerie significant to a bass musical instrument due to its relative purity and the drone is caused by the synchronised avalanche of the sand grains. The pitch of the note that is produced could be based on the size of the grains and each singing sand dune may have its own typical sound pitch.

One study had discovered that different notes created by the sand depended on the size of the grains as well as the speed at which they whistle through the wind and scientists have no clue as to how the flowing grains of sand tend to sound like music in the first place.

However, the precise reason for the grain synchronization is yet debated among various scientists and more research needs to be done and understood as to why a few of the dunes boom while the others tend to remain silent. Examples of singing sand dunes are in California’s Kelso Dunes, Eureka Dunes, sugar sand beaches and Warren Dunes in South-western Michigan, Sand Mountain in Nevada and much more.