low frequency

Islanders in the Outer Hebrides say their lives are being disrupted by a mysterious low frequency humming sound that can be heard day and night.

Volcanic earthquakes have a characteristic signature of low frequency wave forms and these have not been exhibited here.

The challenge, Revel said, is that it relies on a standard that “doesn’t take into account all the frequencies and certainly doesn’t take into account the low frequencies that travel further.”

However, their effects are extremely weak and have been discovered only in relatively low frequency band using the method of interferometry.

On a visit to a Texas ostrich farm, the researchers recorded 11 types of calls, ranging from high frequency peeps and gurgles in baby ostriches to low frequency boos and booms in adult males.