Japan Geoscience Union Meeting 2025

Presentation information

[J] Oral

M (Multidisciplinary and Interdisciplinary) » M-TT Technology & Techniques

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

Wed. May 28, 2025 9:00 AM - 10:30 AM 104 (International Conference Hall, Makuhari Messe)

convener:Masa-yuki Yamamoto(Department of systems engineering, Kochi University of Technology), Yasuhiro Nishikawa(Division of Math, Sciences, and Information Technology in Education, Environment and Safety Sciences Course Osaka Kyoiku University), Mie Ichihara(Earthquake Research Institute, University of Tokyo), Takayuki Otsu(Japan Weather Association), Chairperson:Yasuhiro Nishikawa(Kochi University of technology. School of System Engineering.), Hiroaki Saito(Cosmosciences, Hokkaido University)

9:30 AM - 9:45 AM

[MTT39-03] Trial observation to identify environmental noise sources in I30JP

*Makiko Iwakuni1, Nobuo Arai1, Takayuki Otsu1, RYOHEI EMURA1, Takanari Fujii1, Masashi Motohashi1 (1.JAPAN WEATHER ASSOCIATION)

Keywords:Infrasound as environmental noise

Japan Weather Association (JWA) has maintained and managed the infrasound array station (Sensor: MB2000, manufactured by CEA/DASE. Station Code: I30JP) in Chiba Prefecture since 2005, as a component of the International Monitoring System for CTBT's verification scheme. I30JP has 6 elements.
Direction of arrival will be estimated from the time difference between each element using cross-correlation analysis in array observation. To understand the azimuth and dominant frequency and of normally observed signals with I30JP (corresponding to environmental noise) will be useful in identifying signals due to unforeseen events. Following the environmental noise classification method introduced by the Romanian NDC at ITW2022, one year's I30JP cross-correlation analysis results clearly showed different plot dispersion in the frequency and azimuth between artificial sources such as refineries and power plants and natural sources such as microbaroms.
A chemical plant is located 300m southeast of one of the I30JP elements, I30H4. I30JP detected environmental noise from that direction. It is expected that the direction of arrival will change if the element location is changed. To confirm whether the chemical plant is really emitting environmental noise, we attempted observation near the chemical plant in a different direction from I30H4. We will introduce temporary observation and results.