Liquefaction-lateral flow features and minor faults in Pleistocene in the southeastern area of Ibaraki Prefecture, Japan

DOI Web Site 32 References

Bibliographic Information

Other Title
  • 茨城県南東部の更新統で確認された液状化-側方流動の痕跡と小断層群の形成
  • イバラキケン ナントウブ ノ コウシントウ デ カクニン サレタ エキジョウカ ソクホウ リュウドウ ノ コンセキ ト ショウダンソウグン ノ ケイセイ

Search this article

Abstract

An outcrop showing paleoseismic liquefaction evidence was found in the middle-upper Pleistocene in the southeastern area of Ibaraki Prefecture. Liquefaction-lateral flow features (2m thick) are seen at the lower part of this outcrop. Normal faults develop in a non-liquidized layer (more than 8m thick) lying above them. The lowest limits of those faults all disappear at the liquidized layer, and liquidized materials intrude along the fault planes. This indicates that both the liquefaction and faults occurred simultaneously. In the surrounding of this outcrop, soft-sediment deformation structures are seen at the upper Pleistocene. These deformation structures are assumed to have been induced by an earthquake about 120,000 years ago. The event of above-mentioned liquefaction-faults is supposed to have been induced by the same earthquake. Therefore it is supposed that about 120,000 years ago an earthquake caused the liquefaction in the layer of 220,000-230,000 years old, which was lying 10-12m deep from the ground surface. Lateral flow induced the failure of the upper layer.

Journal

References(32)*help

See more

Keywords

Details 詳細情報について

Report a problem

Back to top