東北地方中部地域の電気伝導度構造

• 藤縄 幸雄

  防災科学技術研究所

• 川上 則明

  地熱技術開発 (株)

• 上嶋 誠

  東京大学地震研究所

• 本蔵 義守

  東京工業大学

書誌事項

タイトル別名

• Georesistivity Structure in the Central Part of North-Eastern Japan Arc
• トウホク チホウ チュウブ チイキ ノ デンキ デンドウド コウゾウ

抄録

Magnetotelluric (MT) measurements on three transects have been obtained in the central Tohoku district of the northeastern Japan, where the Pacific plate subducts beneath the Eurasian plate. In this report observations and analysis of the MT data on the northernmost line (known as Line A) of 33 sites are described. Broadband magnetotelluric sounding data (0.00005-1, 000s period) were collected at the points along the line A of about 140km length running approximately east-west. Measurements at two sites on each transect about 70km apart were conducted simultaneously for the sake of remote-reference data analysis.<br>The impedance- and tipper- strikes show roughly north-south structural direction in spite of variable distributions both in space and frequency suggesting a considerably complex feature of the resistivity structure in the region. We assumed a two-dimensional structure running roughly north-south. Both strike-parallel and strike-perpendicular components of the MT apparent resistivity and phase data of the broadband measurement were subjected to a modified Rapid Relaxation Inversion to obtain an approximate two-dimensional smooth resistivity model for the northernmost transect, which was compared with the one-dimensional model through the coordinate invariant apparent resistivity. The two-dimensional model indicates that there are six conductive anomalies of several ohm·m with different degree of plausibility, for instance, at Japan Sea side of Tohoku, Central Basin Range and Kitakami River region. Those conductive regions are suggested to be Quaternary sediment layers. The resistivity structure is discussed with reference to the seismic velocity distribution, Q-value of the seismic wave attenuation, seismicity, and temperature distribution.

収録刊行物

• 地震　第２輯

  地震　第２輯 50 (4), 357-376, 1998

  公益社団法人 日本地震学会

キーワード

• Resistivity
• Northeastern Japan Arc
• Seismicity
• Seismic velocity
• <i>Q</i>-value

詳細情報

• CRID: 1390001204307311488
• NII論文ID: 10002501418
• NII書誌ID: AN00305741
• DOI: 10.4294/zisin1948.50.4_357
• ISSN: 18839029
• ISSN: 2186599X
• ISSN: 00371114
• NDL書誌ID: 4435004
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I4435004
• Web Site: https://www.jstage.jst.go.jp/article/zisin1948/50/4/50_4_357/_pdf
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