Phys.org   November 16, 2021 Earthquakes, volcanic eruptions, and even severe weather events produce a medley of low-frequency infrasound waves below the range of human hearing. Infrasound waveforms generated by natural and anthropogenic phenomena contain important clues about the size and nature of the event. A team of researchers in the US (Sandia National Laboratory, Caltech) has shown that sensors on balloons in the lower stratosphere can record faithful representations of the near-source acoustic wave field at unprecedented range. The acoustic signature of a buried chemical explosion recorded at a range of 56 km and an altitude of 21.8 km was […]