Infrasound is sound of low frequency, below that which we can hear. Volcanoes produce a lot of infrasound when they explode. Recently it has become a valuable monitoring technique at various volcanoes around the world. The signal produced is less complex that a seismic signal since it passes though the air which has a far less complex structure than the ground. The data can be used to investigate the source mechanism of explosions, pinpoint its origin within a multiple vent system (like Volcán de Colima), and determine depths.
Three stations have been installed, each combining infrasound monitoring with thermal. The stations are located at a distance of 1.5, 2.5 and 6 km from the summit.
Sensors used are the following:
A great source of information is run by our collaborator Jeff Johnson.