5:15 PM - 7:15 PM
[MTT39-P02] Array Observation and Microbaroms Analysis at Atsugi and Kawaguchiko Using a New Microbarometer
Keywords:Microbaroms, Infrasound, Microbarometer, Volcano
Abstract
Microbarometers are used to observe infrasound generated by geophysical-scale phenomena such as volcanic eruptions, tsunamis, and earthquakes. Recently, our team at Krone Corporation developed a new microbarometer with a resolution of 10 mPa. We have confirmed that this new microbarometer was capable of detecting microbaroms with amplitudes of 100-200 mPa in a test room. In this study, as a next step, we investigate the performance of this microbarometer for practical deployment in the field. Specifically, we aimed to identify the waveform of microbaroms and apply array processing to estimate the direction of arrival of the microbarom propagation. Through this study, we discuss the effectiveness of this microbarometer as an infrasound observation instrument and its potential application for disaster prevention.
With the advice and support of JAMSTEC and Mount Fuji Research Institute, Yamanashi Prefectural Government (MFRI), we installed two microbarometer arrays, each consisting of three new microbarometers, with an aperture of 2 km. One array was installed in Atsugi and Isehara City (Atsugi Array), while the other was deployed around Lake Kawaguchi (Kawaguchiko Array). Each microbarometer is equipped with a GPS antenna for time synchronization. Observation data are stored on an external SSD and collected regularly. Because microbaroms are known to have a characteristic frequency of approximately 0.2 Hz, we performed spectral analysis to identify their occurrence times. Then, we examined the waveforms to determine the time lags between coherent signals, and estimated the direction of arrival based on the distances and time lags between observation points in the array.
Spectral analysis of the observed data from October 10, 2024, to January 20, 2025, showed a peak at 0.2 Hz on several dates. This suggests that strong microbaroms occurred during the observation period and were successfully detected by the new microbarometer. We primarily analyzed two prominent waveforms. Array analysis revealed that both waveforms arrived at approximately acoustic velocity, indicating that they were microbaroms. However, the directions of arrival were opposite between the Atsugi Array and the Kawaguchiko Array. Additionally, these directions deviated slightly from the direction of the high coastal wave region (the costal wave map, the Japan Meteorological Agency), which was expected to be a source of microbaroms. We are now investigating the cause of these direction differences. Although consistent results were not obtained in Atsugi Array and Kawaguchiko Array in this study, the successful detection of microbaroms suggests that this new microbarometer has the potential to detect infrasound from various natural phenomena.
Acknowledgment
We appliciate Yoshio Fukao and Taewoon Kim of the Japan Agency for Marine-Earth Science and Technology for their guidance on microbaroms and their observation methods. We also thank Toshiaki Kitajima and Kouta Imai of Mitomi Giken co., ltd. for their valuable advice on the configuration and installation of the observation equipment. We are grateful to Kansenji Soto Mission, Jishukan Secondary School, and Mitomi Giken co., ltd. in Atsugi Array, as well as Fujikawaguchiko-machi Kodachi Elementary School, Fujikawaguchiko-machi Oishi Elementary School, and Fujikawaguchiko-machi Kawaguchiko Kita Junior High School in Kawaguchiko in Kawaguchiko Array for their support in installing the observation stations. The observation points in Fujikawaguchiko-machi were made available through the cooperation of Tomohiro Kubo of Mount Fuji Research Institute, Yamanashi Prefectural Government and the Fujikawaguchiko-machi Board of Education. Kawaguchiko Array was selected for the 2024 Yamanashi-Volcano Disaster Prevention Innovation Pitch Contest, and the observation activities were subsidized by the contest.
Microbarometers are used to observe infrasound generated by geophysical-scale phenomena such as volcanic eruptions, tsunamis, and earthquakes. Recently, our team at Krone Corporation developed a new microbarometer with a resolution of 10 mPa. We have confirmed that this new microbarometer was capable of detecting microbaroms with amplitudes of 100-200 mPa in a test room. In this study, as a next step, we investigate the performance of this microbarometer for practical deployment in the field. Specifically, we aimed to identify the waveform of microbaroms and apply array processing to estimate the direction of arrival of the microbarom propagation. Through this study, we discuss the effectiveness of this microbarometer as an infrasound observation instrument and its potential application for disaster prevention.
With the advice and support of JAMSTEC and Mount Fuji Research Institute, Yamanashi Prefectural Government (MFRI), we installed two microbarometer arrays, each consisting of three new microbarometers, with an aperture of 2 km. One array was installed in Atsugi and Isehara City (Atsugi Array), while the other was deployed around Lake Kawaguchi (Kawaguchiko Array). Each microbarometer is equipped with a GPS antenna for time synchronization. Observation data are stored on an external SSD and collected regularly. Because microbaroms are known to have a characteristic frequency of approximately 0.2 Hz, we performed spectral analysis to identify their occurrence times. Then, we examined the waveforms to determine the time lags between coherent signals, and estimated the direction of arrival based on the distances and time lags between observation points in the array.
Spectral analysis of the observed data from October 10, 2024, to January 20, 2025, showed a peak at 0.2 Hz on several dates. This suggests that strong microbaroms occurred during the observation period and were successfully detected by the new microbarometer. We primarily analyzed two prominent waveforms. Array analysis revealed that both waveforms arrived at approximately acoustic velocity, indicating that they were microbaroms. However, the directions of arrival were opposite between the Atsugi Array and the Kawaguchiko Array. Additionally, these directions deviated slightly from the direction of the high coastal wave region (the costal wave map, the Japan Meteorological Agency), which was expected to be a source of microbaroms. We are now investigating the cause of these direction differences. Although consistent results were not obtained in Atsugi Array and Kawaguchiko Array in this study, the successful detection of microbaroms suggests that this new microbarometer has the potential to detect infrasound from various natural phenomena.
Acknowledgment
We appliciate Yoshio Fukao and Taewoon Kim of the Japan Agency for Marine-Earth Science and Technology for their guidance on microbaroms and their observation methods. We also thank Toshiaki Kitajima and Kouta Imai of Mitomi Giken co., ltd. for their valuable advice on the configuration and installation of the observation equipment. We are grateful to Kansenji Soto Mission, Jishukan Secondary School, and Mitomi Giken co., ltd. in Atsugi Array, as well as Fujikawaguchiko-machi Kodachi Elementary School, Fujikawaguchiko-machi Oishi Elementary School, and Fujikawaguchiko-machi Kawaguchiko Kita Junior High School in Kawaguchiko in Kawaguchiko Array for their support in installing the observation stations. The observation points in Fujikawaguchiko-machi were made available through the cooperation of Tomohiro Kubo of Mount Fuji Research Institute, Yamanashi Prefectural Government and the Fujikawaguchiko-machi Board of Education. Kawaguchiko Array was selected for the 2024 Yamanashi-Volcano Disaster Prevention Innovation Pitch Contest, and the observation activities were subsidized by the contest.