Infrasound Laboratory University of Hawaii

Volcano Infrasound

Q: Can infrasound be used to forecast eruptions?

A. For open-vent systems, yes. As demonstrated at Sakurajima Volcano, Japan, long-period events can be recorded with both seismic and infrasonic sensors to observe changes in the recurrence and intensity of an eruption. This information can be used to issue warnings and forecasts.

Q. What about close-vent systems?

A. Infrasound cannot be used for forecasts if there is no baseline acoustic activity. However, it can provide an accurate measure of the explosion onset, intensity, and duration that can be used for aviation warnings and ash transport models.

Q. Would infrasound replace existing monitoring technology.

A. No. Infrasound can reduce false alarm rates from seismic monitoring systems and can provide continuous real-time coverage of atmospheric processes during adverse whether. Infrasound would complement existing optical, seismic, and chemical methods - esentially adding an extension of our sense of hearing to the existing projections of our sense of sight, touch and smell/taste.

Q. Do the acoustic microphones need to be near an active crater?

A. No. Volcanic craters are some of the worst places for long-term deployment of microphones, which are very sensitive to wind noise. Not only are volcanic craters and slopes windy, but they tend to be unstable and to get buried by molten or incandescent rocks, placing instrumentation and lives at risk. Infrasound can be efficiently used for remote sensing of volcanoes at ranges varying from kilometers (low-intensity eruptions) to hundreds of kilometers (intense eruptions).