1984年長野県西部地震の破壊域におけるS波偏向異方性

• 佐伯 龍男

  京都大学理学部地震予知観測地域センター 現所属: 石油公団

• 梅田 康弘

  京都大学理学部阿武山地震観測所

書誌事項

タイトル別名

• Shear-wave Polarizations in the Rupture Region of the 1984 Western Nagano Prefecture Earthquake
• 1984ネン ナガノケン セイブ ジシン ノ ハカイイキ ニ オケル Sハ ヘ

抄録

The high accelerations exceeding the earth's gravity were observed on the small area near the main shock of the 1984 Western Nagano Prefecture Earthquake (M=6.8). Few aftershocks occurred in this small high acceleration spot of main fault. It is inferred that great destruction producing the high accelerations occurred within this small spot. For detecting the evidence of great destruction, we tried to investigate the crack orientation and density by using Shear-wave polarization method.<br>We have identified that directions of polarization in and out of the high acceleration spot are N40-70°W. These directions are consistent with the axis of maximum compression obtained from earthquake fault mechanisms and geodetic surveys. There are no difference in polarizations between in- and out of the high acceleration spot. It suggests that open-cracks had been made before the main shock. Great destructions of the main shock seems to have little influences on S-wave polarization. The average time-lag between arrival of leading and slower shear-wave is 0.02^S. It indicates that present open-cracks are distributed in a shallow depth.

収録刊行物

• 地震　第２輯

  地震　第２輯 41 (2), 163-171, 1988

  公益社団法人 日本地震学会

詳細情報

• CRID: 1390001204306209536
• NII論文ID: 130006788022
• NII書誌ID: AN00305741
• DOI: 10.4294/zisin1948.41.2_163
• ISSN: 18839029
• ISSN: 2186599X
• ISSN: 00371114
• NDL書誌ID: 3203615
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I3203615
• Web Site: https://www.jstage.jst.go.jp/article/zisin1948/41/2/41_2_163/_pdf
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