[M-TT38] Brand-new scope of coupling geophysics being established by infrasound and associated waves

[MTT38-P01] Detection of infrasound sources using three-years array data in 2019-2021 deployed at the Lützow-Holm Bay region, Antarctica

★Invited Papers

*Masaki Kanao¹, Murayama Takahiko⁵, Masa-yuki Yamamoto², Yoshiaki Ishihara³, Dan Muramatsu⁴ (1.National Institute of Polar Research, 2.Kochi University of Technology, 3.Japan Aerospace Exploration Agency, 4.Earthquake Research Institute, The University of Tokyo, 5.Japan Weather Association)

Keywords:infrasound, array analysis, Lützow-Holm Bay, Antarctic coast, cryosphere dynamics

Time-space variations of infrasound source locations for three years of 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 frequency content as well as propagating directions during the whole three years. A large number of infrasound sources were detected and many of them revealed to be located between northward and north-westward directions viewed from the arrays. These source events are generated within the Southern Indian Ocean and the northern part of LHB with frequency content of few seconds; that is the “microbaroms” originated from oceanic swells. From austral summer to fall seasons, in contrast, many infrasound sources orientation are determined to be north-eastward direction. These sources might be related to the effects of katabatic winds in the continental coastal area. Furthermore, several sporadic occurring infrasound events during wintering seasons had predominant frequency content of few Hz, which were clearly higher than those of the microbaroms. On the basis of a comparison with sea-ice and glacier distribution form MODIS satellite images, these high-frequency sporadic sources were considered to be cryo-seismic signals associated with cryosphere dynamics near the local arrays. In these regards, infrasound wave could be an useful tool for monitoring surface environment involving meteorological variations in the coastal area of Antarctica.