JpGU-AGU Joint Meeting 2017

講演情報

[EJ] 口頭発表

セッション記号 S (固体地球科学) » S-SS 地震学

[S-SS10] [EJ] 地殻変動

2017年5月22日(月) 09:00 〜 10:30 コンベンションホールB (国際会議場 2F)

コンビーナ:道家 涼介(神奈川県温泉地学研究所)、落 唯史(国立研究開発法人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)、座長:西村 卓也(京都大学防災研究所)、座長:中尾 茂(鹿児島大学大学院理工学研究科地球環境科学専攻)

10:00 〜 10:15

[SSS10-05] Post-seismic deformation of 2016 Kumamoto Earthquake by continuous 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 (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)

キーワード:GNSS連続観測、余効変動

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 was observed 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-seismic deformation. Thirteen of our twenty-one sites were near Futagawa and Hinagu fault zones, four of our sites were around Aso Volcano, which is east from Futagawa fault zones and the others were in Ohita Prefecture, which is east of Kumamoto Prefecture

Bernese GNSS Software Ver. 5.2 is used for GNSS data analysis of our newly sites together with GEONET and 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 and Futagawa 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 is located 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 two faults, one is located in Futagawa fault zone and the other is Hinagu fault zone. Fault parameters of length, width, strike, dip, amount of slip, position are estimated by simulated annealing method. Top and 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.