The Kozu-Matsuda Fault: Its Recent Behavior and Tectonic Significance in a Plate Convergent Region.

DOI Web Site 2 Citations 29 References

Bibliographic Information

Other Title
  • 国府津・松田断層の最新活動史と地震テクトニクス
  • コウズ マツダ ダンソウ ノ サイシン カツドウシ ト ジシン テクトニクス
  • Its Recent Behavior and Tectonic Significance in a Plate Convergent Region

Search this article

Abstract

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.

Journal

Citations (2)*help

See more

References(29)*help

See more

Keywords

Details 詳細情報について

Report a problem

Back to top