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JpGU-AGU Joint Meeting 2017

Post-seismic deformation of 2016 Kumamoto Earthquake bycontinuous GNSS network*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
*Shigeru Nakao1, Takeshi Matsushima2, Takao Tabei3, Makoto OKUBO4, Tadashi Yamashina4,Takahiro Ohkura5, Takuya NISHIMURA6, Takuo Shibutani6, Masahiro Teraishi6, Takeo Ito7,Takeshi Sagiya8, Kenjiro Matsuhiro7, Teruyuki Kato9, Jun'ichi Fukuda9, Atsushi Watanabe9,Satoshi Miura10, Yusaku Ohta10, Tomotsugu Demachi10, Hiroaki Takahashi11, Mako Ohzono11,Teruhiro Yamaguchi11, Kazumi Okada11
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. 高知大学理学部応用理学科、4. 高知大学理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
1. Department of Earth and Environmental Sciences, Graduate School of Science and Engineering, Kagoshima
University, 2. Institute of Seismology and Volcanology, Faculty of Sciences, Kyushu University, 3. Department ofApplied Science Department, Faculty of Science, Kochi University, 4. Kochi Earthquake Observatory, Faculty ofScience ,Kochi University, 5. Aso Volcanological Laboratory, Institute for Geothermal Sciences, Graduate School ofScience, Kyoto University, 6. Disaster Prevention Research Institute, Kyoto University, 7. Earthquake and Volcano
Research Center, Graduate School of Environmental Studies, Nagoya University, 8. Disaster Mitigation ResearchCenter, Nagoya University, 9. Earthquake Research Institute, University of Tokyo, 10. Research Center for Predictionof Earthquakes and Volcanic Eruptions, Graduate School of Science, Tohoku University, 11. Institute of Seismology
and Valcanology, Graduate School of Science, Hokkaido University

The 2016 Kumamoto Earthquake (M 7.3) attacked to Kumamoto prefecture in Japan on April 16, 2016.
Seismic intensity 7 was observed twice in the 2016 Kumamoto Earthquake. Post-seismic deformation wasobserved after the large earthquake occurred in land and trench. Twenty-one continuous GNSS
observation sites were occupied after the 2016 Kumamoto Earthquake to observed post-seismicdeformation. Thirteen of our twenty-one sites were near Futagawa and Hinagu fault zones, four of oursites were around Aso Volcano, which is east from Futagawa fault zones and the others were in OhitaPrefecture, which is east of Kumamoto Prefecture
Bernese GNSS Software Ver. 5.2 is used for GNSS data analysis of our newly sites together with GEONETand JMA GNSS sites for volcanoes in Kyushu for the period from April 15 to December 31, 2016. We used
CODE precise ephemerides and CODE Earth rotation parameters. The coordinates of the GNSS sites are
estimated respect to ITRF2008.
Large post-seismic deformation in horizontal component was observed at CGNSS sites near Hinagu andFutagawa fault zone. However, there is almost no observation in vertical component. Largest post-seismic
deformation of 11cm from April to December, 2016 is observed in NS-component at MIFN, which islocated east side of Hinagu fault zone. It seems that post-seismic deformation does not come to stop.
After slip model is assumed for initial post-seismic deformation from April to July, 2016. We assumed twofaults, one is located in Futagawa fault zone and the other is Hinagu fault zone. Fault parameters oflength, width, strike, dip, amount of slip, position are estimated by simulated annealing method. Top and©2017. Japan Geoscience Union. All Right Reserved.

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JpGU-AGU Joint Meeting 2017

bottom of fault plane are 0.1 to 40 km in Hinagu fault and 0.8 to 32 km in Futagawa fault. Two fault
planes extended to mantle. It suggests that there are several phenomena in initial post-seismic
deformation, effect of viscoelastic etc.
キーワード：GNSS連続観測、余効変動
Keywords: Continuous GNSS observation, post-seismic deformation©2017. Japan Geoscience Union. All Right Reserved.

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