[S-SS09] 地殻変動

[SSS09-P04] Post-seismic deformation of 2016 Kumamoto Earthquake by continuous GNSS network (2)

*中尾 茂¹、松島 健²、田部井 隆雄³、大久保 慎人⁴、山品 匡史⁴、大倉 敬宏⁵、西村 卓也⁶、澁谷 拓郎⁶、寺石 眞弘⁶、伊藤 武男⁷、鷺谷 威⁸、松廣 健二郎⁷、加藤 照之⁹、福田 淳一⁹、渡邉 篤志⁹、三浦 哲¹⁰、太田 雄策¹⁰、出町 知嗣¹⁰、高橋 浩晃¹¹、大園 真子¹¹、山口 照寛¹¹、岡田 和見¹¹ (1.鹿児島大学大学院理工学研究科地球環境科学専攻、2.九州大学大学院理学研究院附属地震火山観測研究センター、3.高知大学理工学部地球環境防災科学科、4.高知大学理工学部附属高知地震観測所、5.京都大学大学院理学研究科附属地球熱学研究施設火山研究センター、6.京都大学防災研究所、7.名古屋大学大学院環境学研究科附属地震山研究センター、8.名古屋大学減災連携研究センター、9.東京大学地震研究所、10.東北大学大学院理学研究科附属地震・噴火予知研究観測センター、11.北海道大学大学院理学研究院附属地震火山研究観測センター)

キーワード：GNSS連続観測、余効変動、2016年熊本地震

Post-seismic deformation has been observed since April 15, 2016 by extraordinary GNSS observations of 20 sites and cooperative GNSS observations of 15 sites by Kyushu University, Kyoto University and Kagoshima University. Extraordinary GNSS sites started observation in April, 2016 after occurrence of 2016 Kumamoto Earthquake. Cooperative GNSS observations have observed continuously before the earthquake. Bernese GNSS Software V. 5.2 are used for GNSS data analysis with GEONET data, which is operated by GSI and JMA GNSS continuous data in Kyushu. CODE precise ephemerides and Earth rotation pole data are used.
Plate motion in each site should be removed from post-seismic deformation data. Displacement velocities of GNSS sites are estimated by Least Squares method in the period from 2004 to 2013. Displacement velocities of extraordinary GNSS sites are interpolated by velocities around the sites. Post-seismic deformation is derived by extracting the displacement velocity of plate motion.
Post-seismic deformation is observed at sites which are located on the south-east side of Hinagu fault, especially on NS component until December 2017. It seems that clear post-seismic deformation continues until early part of June, 2016 at sites which are located on the north-west side of Hinagu faults. Change in NS component around May, 2017 and in EW component around August, 2017 occurred at sites which are located on both sides of Hinagu fault.