Seismo-acoustic detection and localization of iceberg collapse in Atka Bay, Antarctica

On 12 January 2022, an iceberg collapsed at the edge of frozen Atka Bay, Antarctica. The event generated seismic, hydroacoustic, and atmospheric infrasound waves recorded by a local network comprising land- and ice-based seismometers, an underwater hydrophone, and an on-ice infrasound array. Analysis of the seismic and hydroacoustic data shows that the collapse occurred in at least three stages separated by 16 and 10 s. The first stage produced a head wave, a P body-wave, and a Rayleigh wave, while later stages were dominated by surface waves. Infrasound data reveal multiple overlapping arrivals likely caused by direct propagation and partial atmospheric reflections. Two localization techniques were benchmarked: azimuthal cross-bearing and a Bayesian joint inversion using time differences of arrival. Both approaches accurately located the iceberg within a few hundred meters of its geo-location. These unique observations underscore the value of continuous seismo-acoustic monitoring for investigating local cryopheric dynamics.