Upsweep (unidentified sound)

As Upsweep a noise is called, which is recorded by hydrophones of the National Oceanic and Atmospheric Administration with the help of the Equatorial Pacific Ocean autonomous hydrophone array of the U.S. Navy in the Pacific Ocean since 1991. The cause of the noise is unknown, the place of origin is given roughly by 54 ° S, 140 ° W -54- 140. In this area, seismic activity of volcanic origin are known.

The noise lasts for a few seconds and is recurrent. Its volume is high enough to be measured in the entire Pacific. The intensity of seasonal variations with maxima in spring and autumn.