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S wave attenuation structure on the western side of the Nankai subduction zone: Implications for fluid distribution and dynamics
https://nied-repo.bosai.go.jp/records/4014
https://nied-repo.bosai.go.jp/records/4014692a1af8-29c8-488e-b3be-546226f963e7
| Item type | researchmap(1) | |||||||||||||||||
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| 公開日 | 2023-03-30 | |||||||||||||||||
| タイトル | ||||||||||||||||||
| 言語 | en | |||||||||||||||||
| タイトル | S wave attenuation structure on the western side of the Nankai subduction zone: Implications for fluid distribution and dynamics | |||||||||||||||||
| 言語 | ||||||||||||||||||
| 言語 | eng | |||||||||||||||||
| 著者 |
Tsutomu Takahashi
× Tsutomu Takahashi
× Koichiro Obana
× Yojiro Yamamoto
× Ayako Nakanishi
× Shuichi Kodaira
× Yoshiyuki Kaneda
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| 抄録 | ||||||||||||||||||
| 内容記述タイプ | Other | |||||||||||||||||
| 内容記述 | We estimated the S wave attenuation structure in southwestern Japan and the western Nankai Trough by analyzing maximum S wave amplitudes at 4-8, 8-16, and 16-32Hz with a correction term for apparent amplitude attenuation due to multiple forward scattering. Because the estimated attenuation (Q(-1)) in our tomographic study was much larger than Q(-1) due to wide-angle scattering, our estimated Q(-1) was composed mainly of intrinsic attenuation. High-attenuation areas (Q(-1)>1/300 at 4-8Hz) were imaged beneath Quaternary volcanoes and south off Shikoku. Low (<1/1500 at 4-8Hz) or moderate Q(-1) (1/500-1/1000 at 4-8Hz) was imaged beneath Shikoku and nonvolcanic areas of Chugoku. High and moderate Q(-1) in and around Shikoku are located near the top of subducting Philippine Sea Plate. This correspondence implies that these high and moderate Q(-1) reflect fluid in the subducting slab. By applying a theoretical model of attenuation in water-saturated porous random media, we examined wave-induced fluid flow induced by lower frequency (<1Hz) seismic waves that may be related with triggering of nonvolcanic tremor by surface waves. Even though Q(-1) structure in this study cannot fully explain the tremor triggering by wave-induced fluid flow, large uncertainties of Q(-1) in tremor zone suggest that high resolution imaging of Q(-1) and random inhomogeneities would give some constraints for the spatial variation of permeability and other medium properties. Key Points <list list-type="bulleted" id="jgrb50863-list-0001"><list-item id="jgrb50863-li-0001">Attenuation structure is estimated by removing scattering attenuation<list-item id="jgrb50863-li-0002">A rift zone shows a peculiar combination of random inhomogeneity and 1/Q<list-item id="jgrb50863-li-0003">1/Q in subducting slab is examined in terms of fluid distribution and dynamics |
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| 言語 | en | |||||||||||||||||
| 書誌情報 |
en : JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH 巻 119, 号 10, p. 7805-7822 |
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| 出版者 | ||||||||||||||||||
| 言語 | en | |||||||||||||||||
| 出版者 | AMER GEOPHYSICAL UNION | |||||||||||||||||
| ISSN | ||||||||||||||||||
| 収録物識別子タイプ | EISSN | |||||||||||||||||
| 収録物識別子 | 2169-9356 | |||||||||||||||||
| DOI | ||||||||||||||||||
| 関連識別子 | 10.1002/2014JB011103 | |||||||||||||||||
