AGU: Geophysical Research Letters

 

Editors' Highlight

Atmospheric boundary layers muffle signals of volcanic tremor

Acoustic monitoring of volcanic tremor allows scientists to observe changes in eruptive activity, particularly during periods of poor visibility. It complements seismic monitoring by helping scientists differentiate between pressure release near the surface and deeper subsurface activity. To monitor the propagation of low-frequency sound waves (infrasound) from Hawaii's Kilauea volcano, Fee and Garcés (2007) analyzed data from an infrasound array about 12.5 km from the active vent that continuously emits volcanic tremor at a relatively steady rate. Noting that the propagation of infrasound can be masked and muffled by winds and temperature changes at all altitudes, the authors sought to identify how interfaces in the atmosphere bend infrasonic signals. They found that the array hears more volcanic tremor at night, due likely to a nocturnal atmospheric boundary layer refracting sound back down to the array. Thus correct interpretation of volcanic eruptions through infrasonic data requires a thorough knowledge of the regional atmospheric patterns that might disrupt the signal.

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