Subsurface velocity structure and site amplification characteristics in Mashiki Town, Kumamoto Prefecture, Japan, inferred from microtremor and aftershock recordings of the 2016 Kumamoto earthquakes

• Material Type: 記事
• Title: Subsurface velocity structure and site amplification characteristics in Mashiki Town, Kumamoto Prefecture, Japan, inferred from microtremor and aftershock recordings of the 2016 Kumamoto earthquakes
• Author/Editor: Takumi Hayashida; Masumi Yamada; Masayuki Yamada
• Publication, Distribution, etc.: 日本 : Springer Nature
• Publication Date: 2018-07-11
• Publication Date (W3CDTF): 2018-07-11
• Periodical title: EPS : Earth, Planets and Space
• No. or year of volume/issue: 70(116)
• Volume: 70(116)
• ISSN (Periodical Title): 1880-5981
• ISSN-L (Periodical Title): 1343-8832
• Text Language Code: eng
• DOI: 10.1186/s40623-018-0889-2; https://doi.org/10.1186/s40623-018-0889-2
• Persistent ID (NDL): info:ndljp/pid/11125884; https://dl.ndl.go.jp/pid/11125884
• Collection: 障害者向け資料
• Collection (Materials For Handicapped People:1): テキストデータ
• Collection (particular): 国立国会図書館デジタルコレクション > 電子書籍・電子雑誌 > その他; https://dl.ndl.go.jp/collections/B00035
• Acquisition Basis: オンライン資料収集制度
• Date Accepted (W3CDTF): 2018-08-10T20:26:03+09:00
• Date Captured (W3CDTF): 2018-08-10
• Format (IMT): application/pdf
• Access Restrictions: 国立国会図書館内限定公開
• Service for the Digitized Contents Transmission Service: 図書館・個人送信対象外
• Availability of remote photoduplication service: 可
• Periodical Title (URI): https://earth-planets-space.springeropen.com/articles
• Periodical Title (Persistent ID (NDL)): info:ndljp/pid/11067456; https://dl.ndl.go.jp/pid/11067456
• Data Provider (Database): 国立国会図書館 : 国立国会図書館デジタルコレクション; https://dl.ndl.go.jp

• Summary, etc.: In order to investigate the seismic velocity structure in the region of concentrated severe damage during the 2016 Kumamoto earthquake sequence, we conducted continuous seismic observations in the central area of Mashiki Town, Kumamoto Prefecture. During 4 days of observations at eight temporary sites, 2 months after the mainshock, recordings from 30 aftershocks (1.7 ≤ Mj ≤ 4.3, 1.9 km ≤ depth ≤ 13.5 km) were obtained. The aftershock data showed that site amplifications at approximately 1 Hz are dominant in a zone where almost no buildings were damaged along the Akitsu riverside, whereas site amplifications at higher than 3 Hz are observed in the heavily damaged zones. Our data also showed that the peak acceleration and velocity amplitudes, as well as seismic intensities for the small events in the less damaged zone, are clearly larger than those in the damaged zones, implying that the damage distribution is inconsistent with site response based on linear site amplifications. The estimated phase velocities of Rayleigh waves using the aftershock and microtremor data show dispersive characteristics in the lower frequency range (0.26 ≤ f ≤ 1.27 Hz), but the values are substantially smaller than those derived from the P–S logging model at the nearest KiK-net strong-motion observation station KMMH16. The derived microtremor horizontal-to-vertical spectral ratios and earthquake radial-to-vertical (R/V) spectral ratios show common distinct peaks at around 0.4 Hz, which are possibly related to the response of deep sedimentary layers beneath the area. The refined velocity structure model that better accounts for both the phase velocity and common dominant peak indicates that the values of S wave velocity (Vs) above the bedrock layer (Vs = 2700 m/s) are smaller than those inferred from the logging model and the depth to the bedrock layer could be much deeper (about 600 m) in comparison with the logging model (234 m). The derived R/V spectral ratio at station KMMH16 also shows a distinct peak at 0.4 Hz, suggesting that there is no large difference of deep sedimentary structure between the observation area and station KMMH16.
• DOI: 10.1186/s40623-018-0889-2; https://doi.org/10.1186/s40623-018-0889-2
• Access Restrictions: インターネット公開
• Rights (production): © The Author(s) 2018. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.
• Related Material (URI): http://hdl.handle.net/2433/234085; http://id.ndl.go.jp/digimeta/11125884; https://dl.ndl.go.jp/pid/11125884; http://link.springer.com/content/pdf/10.1186/s40623-018-0889-2.pdf; http://link.springer.com/article/10.1186/s40623-018-0889-2/fulltext.html
• Is Referenced By: 2016年熊本地震におけるKiK-net益城と益城町下陳の地震動と建物被害の違いの原因について; https://cir.nii.ac.jp/crid/1390282752337533696
• Data Provider (Database): 国立情報学研究所 : CiNii Research; https://cir.nii.ac.jp/
• Original Data Provider (Database): 学術機関リポジトリデータベース; https://irdb.nii.ac.jp; 雑誌記事索引データベース; https://ndlsearch.ndl.go.jp; Crossref; https://www.crossref.org; CiNii Articles
• Bibliographic ID (NDL): 11125884; http://id.ndl.go.jp/bib/11125884
• NAID: 120006502580