Spectral analysis for precise estimation of seismic attenuation

中島 淳一

講演情報

[E] 口頭発表

セッション記号 S (固体地球科学) » S-SS 地震学

[S-SS04] Seismic Spectra for Source, Subsurface Structure, and Strong-motion Studies

2022年5月23日(月) 10:45 〜 12:15 103 (幕張メッセ国際会議場)

コンビーナ:内出崇彦(産業技術総合研究所地質調査総合センター活断層・火山研究部門)、コンビーナ:Abercrombie Rachel E(Boston University)、Ma Kuo-Fong(Institute of Geophysics, National Central University, Taiwan, ROC)、コンビーナ:染井一寛(一般財団法人地域地盤環境研究所)、座長:内出崇彦(産業技術総合研究所地質調査総合センター活断層・火山研究部門)、Rachel E Abercrombie(Boston University)、Ma Kuo-Fong(Institute of Geophysics, National Central University, Taiwan, ROC)、染井一寛(一般財団法人地域地盤環境研究所)

11:45 〜 12:00

[SSS04-11] Spectral analysis for precise estimation of seismic attenuation

*中島淳一¹ (1.東京工業大学理学院地球惑星科学系)

Spectral analyses of seismic waveforms have been used to estimate source parameters of earthquakes (corner frequency and stress drop) and medium heterogeneity (direct and coda attenuation). However, we often have a strong tradeoff, for example, between corner frequency and attenuation because both parameters control the high-frequency fall-off of each spectrum. We developed a new method to avoid the trade-off using two-step approaches and was able to estimate seismic attenuation with high resolution in space and time (Nakajima et al., JGR, 2013; Nakajima and Uchida, Nature Geoscience, 2018). In this talk, we will present two spectral analysis methods and show that they were able to reveal high-resolution 3D seismic attenuation model and temporal variation in attenuation. The former method will improve our understanding sub-surface attenuation structures associated with magmatism and fault heterogeneity, while the latter one will highlight the migration of fluids along the megathrust boundary and immediately below active volcanoes.