GPS連続観測による長町-利府断層帯およびその周辺 (東北地方中部) の地殻変動

• 西村 卓也

  国土地理院地理地殻活動研究センター

• 鷺谷 威

  名古屋大学大学院環境学研究科地震火山・防災研究センター

• 三浦 哲

  東北大学大学院理学研究科地震・噴火予矢口研究観測センター

書誌事項

タイトル別名

• Crustal Deformation Around the Nagamachi-Rifu Fault Zone and its Vicinity (Central Tohoku), Northeastern Japan, Observed by a Continuous GPS Network
• GPS レンゾク カンソク ニ ヨル ナガマチ リ フ ダンソウタイ オヨビ ソノ シュウヘン トウホク チホウ チュウブ ノ チカク ヘンドウ

抄録

We constructed eight continuous GPS stations across the Nagamachi-Rifu fault zone, northeastern Japan to reveal the detailed spatial pattern of crustal deformation. High strain rate around the fault zone observed by the GEONET and the occurrence of the M_JMA 5.2 Sendai earthquake on September 15, 1998, at the deep edge of the seismogenic part of the fault motivated us to confirm the aseismic sliding of the fault in or below the seismogenic depth from the contemporary deformation. We analyzed the GPS data of new stations as well as existing stations, totaling up to 50 stations in central Tohoku, using GIPSY 2.6.1 software and estimated GPS site velocity and strain rate by a least square method. One component of the principal strain rate shows distinctive compression in the E-W or ESE-WNW direction in the whole region. In the forearc region, the other component of the principal strain rate are almost zero in the south of 38°15′, while NNE-SSW extension in the north of 38°15′. Strain rate distribution is spatially heterogeneous in the region. We found a high strain rate zone west of the Nagamachi-Rifu fault zone and that between Honshu and Awashima in the eastern margin of the Sea of Japan. Low strain rate zones exist in the west of the high strain region of the Nagamachi-Rifu fault zone and in the western half of Yamagata Prefecture. Strain rate distribution pattern on the hanging wall side of the Nagamachi-Rifu fault can be modeled by aseismic sliding of 10mm/yr on a horizontal detachment fault connecting to the Nagamachi-Rifu fault at a depth of about 15km beneath the Ou backbone range. However, it is difficult to constrain a fault model for the strain rate distribution from the present dataset uniquely.

収録刊行物

• 地震　第２輯

  地震　第２輯 56 (4), 497-509, 2004

  公益社団法人 日本地震学会

キーワード

• crustal deformation
• continuous GPS
• the Nagamachi-Rifu fault
• high strain rate region

詳細情報

• CRID: 1390282679282179712
• NII論文ID: 130006787458
• NII論文ID: 10012965633
• NII書誌ID: AN00305741
• DOI: 10.4294/zisin1948.56.4_497
• ISSN: 18839029
• ISSN: 2186599X
• ISSN: 00371114
• NDL書誌ID: 7001036
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I7001036
• Web Site: https://www.jstage.jst.go.jp/article/zisin1948/56/4/56_4_497/_pdf
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