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

[MTT38-P06] Detected examples of infrasonic waves possibly generated by extreme weather and landslides in the surrounding region

*Masa-yuki Yamamoto¹, Shun Ichino¹ (1.Department of systems engineering, Kochi University of Technology)

Keywords:infrasound, regional observation network, extreme weather, soil erosion disaster

Infrasonic waves can be generated mainly by geophysical events such as earthquakes, tsunamis, volcanic eruptions, typhoons, and thunderstorm. We have observed infrasound with establishing Kochi University of Technology (KUT) infrasound observation network since 2016 in Kochi Pref. and expanded it to be wider network with more than 30 sensors, covering from Hokkaido to Kyushu along the Eastern-Southern coast in Japan. In these years, we have reported several detected examples of infrasonic waves generated by earthquakes, volcanic eruptions, and typhoons, however, smaller scale events of extreme weather as well as landslides, resulting in regional soil erosion disasters, can be understood as possible regional infrasound sources. In this talk, we will introduce several clear infrasound events with having rapid and dramatical changes in infrasound overpressure measurements when experiencing somewhat extreme weather conditions with heavy rain, strong wind (so-called gusts/down-bursts), and/or thunderstorm as well as news-reported level regional landslides. Notable issues to be apparent here are 1) there are some status changes in background noise characteristics before and after passing such extreme weather events through the surrounding region about a few tenth km apart from, 2) clear rapid enhancement of infrasonic waves are usually observed a few tenth minutes before the regional weather condition changes. It shows the importance of establishing regional dense infrasound sensor network for making an alert in the focused region, resulting in possible disaster mitigation. Some recent trial activities of constructing such dense observation network with small/low-cost MEMS/microphone sensors will also be presented.