JpGU-AGU Joint Meeting 2020

講演情報

[E] 口頭発表

セッション記号 M (領域外・複数領域) » M-AG 応用地球科学

[M-AG42] CTBT IMS Technologies for Detecting Nuclear Explosion and Their Applications to Earth Science

コンビーナ:Ozel Nurcan Meral(Comprehensive Nuclear-Test-Ban Treaty Organization)、松本 浩幸(国立研究開発法人海洋研究開発機構)、鎌谷 紀子(東京大学地震研究所)、直井 洋介(国立研究開発法人日本原子力研究開発機構)

[MAG42-03] Beyond the antipode: Hydroacoustic detection of earthquake activity along the Middle America Trench

*Dirk Metz1Julien Vergoz2 (1.Japan Agency for Marine-Earth Science and Technology、2.French Alternative Energies and Atomic Energy Commission)

キーワード:CTBT, IMS, Hydroacoustics, Earthquake, Indian Ocean, Diego Garcia

Earthquakes occur regularly along the northern Middle America Trench, a major subduction zone located offshore the Pacific coast of Mexico. Results from phased array beamforming suggest that low-frequency acoustic phases generated by these events couple into the Sound Fixing and Ranging (SOFAR) channel and can be recorded as far as Diego Garcia, Indian Ocean, where a hydrophone triplet station is operated as part of the International Monitoring System (IMS). At more than ~21,300 km, source-receiver ranges exceed antipodal distances (‘suprapodal propagation’), marking the furthest hydroacoustic transmissions to have ever been observed on Earth. Transmission loss modeling indicates that hydroacoustic propagation between the epicenter region and the IMS station is feasible and matches observed travel times. Implications for test-ban monitoring and the potential of the Diego Garcia station for further studying seismic activity along the Middle America subduction system will be discussed.