[M-TT39] Brand-new scope of coupling geophysics being established by infrasound and associated waves

[MTT39-P01] Infrasound migrated sources involving cryosphere dynamics in the Lützow-Holm Bay region, Antarctica

*Masaki Kanao¹, Murayama Takahiko², Masa-yuki Yamamoto³, Yoshiaki Ishihara⁴, Dan Muramatsu⁵, Makiko Iwakuni², Mami Nogami² (1.National Institute of Polar Research, 2.Japan Weather Association, 3.Kochi University of Technoogy, 4.Japan Aerospace Exploration Agency, 5.Earthquake Research Institute, The Univiersity of Tokyo)

Keywords:Infrasound, Lützow-Holm Bay/Antarctica, migrated sources, cryosphere dynamics

Time-space variations of infrasound source locations for three years, 2019-2021, were studied by using 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. Many infrasound sources were detected with many to 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 microbaroms. Based on 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.