Late Quaternary Activity of the Kiotoshi Fault at the South-Eastern Side of the Ono Basin, Fukui Prefecture, Central Japan and its Tectonic Significance

• YAMAMOTO Hirofumi

  Faculty of Education and Regional Studies, Fukui University

Bibliographic Information

Other Title

• 福井県大野盆地南東縁の木落断層の活動度とその意義
• フクイケン オオノ ボンチ ナントウエン ノ キオトシダンソウ ノ カツドウド ト ソノ イギ

Abstract

The Kiotoshi fault is a NNW-trending reverse active fault of a length of 3km in south-eastern side of the Ono basin, Fukui Prefecture. This reverse fault connects NE-trending right-lateral left-stepping faults, and forms a linear boundary between mountainous land and the basin. To make clear the paleoseismic activity of the fault, the fault morphology, the feature of a fault outcrop in a quarry site, and the ¹⁴C dating of buried soil and charcoal samples from the outcrop were examined.<br>The fault displaced the basement rock and overlying fluvial and fan sediments, and makes a gentle step 0.8m high on the fan surface. The amount of vertical displacement of the basement rock is more than 15m. The displacements of the overlying sediments are from 0.5 to 7m or more along the main fault. Buried soil layers, presumably formed by rapid accumulation of fan deposits after faulting events, are present at three horizons in the fan sediments. The calibrated ¹⁴C ages of the buried soils are 2, 850-1, 280 cal yBP, 5, 590-4, 620 cal yBP, 11, 100-8, 810 cal yBP, and the net slips calculated from the vertical displacement of the undeformed buried soil layers are 3.6m, 6.9m and 19 to 20m from the upper layer. The average slip rate of the fault, calculated from the age and the net slip of the lowermost buried soil layer, is 1.7-2.3m/1000 yrs, i. e. the activity of the fault is classified into A class.<br>The Kiotoshi fault is a reverse fault accompanying the NE-trending right-lateral left-stepping faults, but the activities (average slip rate) of these strike-slip faults were considered to be low (class B to C). We need, therefore, to investigate the activities of the surrounding strike-slip faults in order to clarify the late Quaternary tectonic activities of this area.

Journal

• Zisin (Journal of the Seismological Society of Japan. 2nd ser.)

  Zisin (Journal of the Seismological Society of Japan. 2nd ser.) 57 (2), 199-208, 2004

  SEISMOLOGICAL SOCIETY OF JAPAN

Keywords

• Kiotoshi fault
• Sabiraki fault
• Paleoseismology
• Fukui
• Ono basin

Details

• CRID: 1390282679282149504
• NII Article ID: 10014066877
• NII Book ID: AN00305741
• DOI: 10.4294/zisin1948.57.2_199
• ISSN: 18839029
• ISSN: 2186599X
• ISSN: 00371114
• NDL BIB ID: 7208080
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I7208080
• Web Site: https://www.jstage.jst.go.jp/article/zisin1948/57/2/57_2_199/_pdf
• Data Source:
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  • CiNii Articles
  • KAKEN
• Abstract License Flag: Disallowed