Edge wave observation using remote seismoacoustic sensing of ice events in the Arctic

Abstract

As part of the Office of Naval Research Sea Ice Mechanics Initiative, a real‐time monitoring and processing program for acoustic emission from ice fracture and ridge‐building events was established. A wide‐aperture, horizontal hydrophone array was used in combination with a vertical line array to record the acoustic signals, which were then passed through a focused beam former for real‐time generation of ice seismicity maps. A number of rapidly deployable geophone arrays were used in active zones to measure the acoustic emissions in the near field for detailed seismic event analysis. During one such deployment, a highly regular transient arrival structure was recorded on all sensors located near a major lead, with a transient appearing every 5 s. These data have been processed using frequency‐wavenumber analysis to show that the transients correspond to “edge waves” propagating forth and back along the edges of the lead, with the probable source being a “stick‐slip” mechanical phenomenon toward the ends of the lead.