Detection of infrasound sources using three-years array data in 2019-2021 deployed at the Lützow-Holm Bay region, Antarctica

Time-space variations of infrasound source locations for three years, 2019-2021, were studied byusing a combination of two local arrays in the Lützow-Holm Bay region (LHB), Antarctica. The local arrays deployed at two coastal outcrops clearly detected temporal variations in signal frequency content as well as propagating directions during the three years. A large number of infrasound sources were detected with many located to the north and north-west directions from the arrays. These events were generated within the Southern Indian Ocean and the northern part of LHB with frequency-content of a few seconds; these “microbaroms” are believed to originate from oceanic swells. From austral summer to fall additional infrasound sources are determined to be located to the north-east. These sources might be related to the effects of katabatic winds across the continental coastal area. Furthermore, several impulsive infrasound events during the winter had higher predominant frequencies of a few Hz, higher than the microbaroms. On the basis of a comparison of source locations with sea-ice and glacier distribution form MODIS satellite images, these high-frequency sporadic sources may be cryo-seismic signals associated with cryosphere dynamics near the local arrays. These results suggest that infrasound waves can be used to monitor surface environments in the coastal area of Antarctica.