地震時の跳び石と活断層

  • 宇田 進一
    技術士事務所ネットワーク・地球/(財)地震予知総合研究振興会

書誌事項

タイトル別名
  • Active faults and the upthrow of boulders in earthquakes

説明

A boulder on the excavated trench wall just upper part of the Makigahora active fault, a part of the Takayama Oppara active fault zone, in Gifu Prefecture, Japan, is observed. The existence of boulders just upper part of, or several meters apart from, lateral active faults is sometimes observed on the wall of trench. When the sediments are composed of terrace deposit or fan deposit or debris flow, boulders are naturally found. In case of swamp deposit how boulders are derived?<BR>The author hypothesize that boulders a re concentrated by uprhrow in near field strong ground motion in earthquakes. The field survey is conducted along the part of the Makigahora active fault.<BR>As a result of the field survey, boulders are not accidentally concentrated n e a r the fault line, especially several tens meters near the fault line.<BR>Many surveys along surfacer uptures of earthquakes clarified that the distribution of upthrow of boulders corresponds to the area of near field strong ground motion.<BR>When boulders appear just upper part of, or s e v eral meters from, the active fault, especially within swamp deposit, we should treat them carefully as an evidence of the occurrence of strong earthquake. Plants under the boulders show the time of the strong earthquake. The distribution of boulders along active faults might show the strong ground motion area.

収録刊行物

  • Active Fault Research

    Active Fault Research 2002 (22), 33-44, 2002

    Japanese Society for Active Fault Studies

詳細情報 詳細情報について

  • CRID
    1390001204428737408
  • NII論文ID
    130003355621
  • DOI
    10.11462/afr1985.2002.22_33
  • ISSN
    09181024
  • 本文言語コード
    ja
  • データソース種別
    • JaLC
    • CiNii Articles
  • 抄録ライセンスフラグ
    使用不可

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