国府津・松田断層の最新活動史と地震テクトニクス The Kozu-Matsuda Fault:Its Recent Behavior and Tectonic Significance in a Plate Convergent Region

この論文にアクセスする

この論文をさがす

著者

抄録

国府津・松田断層の地震テクトニクス上の位置づけに関しては,現在二つの異なる見解が示されている.一つは,相模トラフ内のセグメントとは独立に活動し,丹沢山地や大磯丘陵を持ち上げる大磯型地震を引き起こすというものである.もう一つは,関東地震を200~300年ごとに引き起こすプレート境界断層から分岐した副断層の一つであり,関東地震と連動することなしに大地震を起こすことはないという考えである.これを検証するため,断層崖の麓で5個所のトレンチ発掘調査を行い,最新の断層活動史を復元した.完新統に明瞭な断層変位は認められなかったが,地辷りや崩壊堆積物から3,000年間に4ないし5回のイベントが識別された.このうち,大規模なイベントは約3,000年前の1回だけで,これが同断層の活動を示すと考えられる.ほかの小規模なイベントは,相模トラフで発生した大地震の可能性があるが,その頻度は数百年という短い間隔ではない.

There are two different ideas about the tectonics of earthquakes along the Kozu-Matsuda fault, which is situated on the on-shore extension of the Sagami trough, central Japan. One is derived from geological evidence of the deformed Quaternary deposits in the onshore areas. The idea is that the Kozu-Matsuda fault upheaves the Oiso Hills and the Tanzawa Mountains and causes huge earthquakes with recurrence intervals thousands of years long. The fault moves without any relationship to the mega-thrust beneath the Sagami Trough from which 1923 Kanto earthquake occurred. The other is that the Kozu-Matsuda fault is a subsidiary fault of the plate boundary thrust along which huge earthquakes occur every two or three hundred years. Several seismological interpretations of the 1923 Kanto earthquake support this opinion. Based on this, the Kozu-Matsuda fault would never cause a huge earthquake without any link to the plate boundary fault. To test these competing hypotheses, the authors reconstructed the recent behavior of the Kozu-Matsuda fault based on the trench logs excavated at the foot of the fault scarp. Although no Holocene fault displacement was found from the trench walls, four or five seismic events since 3, 000 years ago were detected from the startigraphy and chronology of the landslide or slope failure deposits inferred to be of seismic origin. Only one event, which is distinct and occurred about 3, 000 years ago, is recognized to be caused by activity of the Kozu-Matsuda fault. As the other faint events include the event caused by the 1923 Kanto earthquake, these events are thought to be related the earthquakes from the Sagami trough. The trench survey seems to confirm the idea that the Kozu-Matsuda fault and the earthquake from the Sagami Trough have long recurrence intervals and that the last event of the Kozu-Matsuda fault occurred 3, 000 years ago.

収録刊行物

  • 第四紀研究  

    第四紀研究 38(6), 447-460, 1999-12-01 

    Japan Association for Quaternary Research

参考文献:  29件

参考文献を見るにはログインが必要です。ユーザIDをお持ちでない方は新規登録してください。

各種コード

  • NII論文ID(NAID)
    10004721276
  • NII書誌ID(NCID)
    AN0034136X
  • 本文言語コード
    JPN
  • 資料種別
    ART
  • ISSN
    04182642
  • NDL 記事登録ID
    4927014
  • NDL 雑誌分類
    ZM49(科学技術--地球科学--地質)
  • NDL 請求記号
    Z15-67
  • データ提供元
    CJP書誌  NDL  J-STAGE 
ページトップへ