Seismological and geological characterization of the crust in the southern part of northern Fossa Magna, central Japan

Hiroshi Sato, Takaya Iwasaki, Yasutaka Ikeda, Tetsuya Takeda, Nobuhisa Matsuta, Tomoko Imai, Eiji Kurashimo, Naoshi Hirata, Sin'ichi Sakai, Driss Elouai, Taku Kawanaka, Shinji Kawasaki, Susumu Abe, Takeshi Kozawa, Takeshi Ikawa, Yoshimasa Arai, Naoko Kato

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

The northern Fossa Magna (NMF) is a Miocene rift basin formed in the final stages of the opening of the Sea of Japan. The northern part of Itoigawa-Shizuoka Tectonic Line (ISTL) bounds the western part of the NMF and forms an active fault system that displays one of the largest slip rates in the Japanese islands. Reflection and refraction/wide-angle reflection profiling and earthquake observations by a dense array were undertaken across the northern part of ISTL in order to delineate structures in the crust, and deep geometry of the active fault systems. The ISTL active fault system at depth (ca. 2 km) shows east-dipping low-angle in Omachi and Matsumoto and is extended beneath the Central Uplift Zone and Komoro basin keeping the same dip-angle down to ca. 15 km. The upper part of the crust beneath the Central Uplift Zone is marked by the high Vp and high resistivity zone. Beneath the folded zone of the NMF, the middle to lower crust shows low Vp, low resistivity and more reflective features. The balanced geologic cross-section based on the reflection profiles suggests that the shortening deformation since the late Neogene was produced by the basin inversion of the Miocene low-angle normal fault.

Original languageEnglish
Pages (from-to)1253-1259
Number of pages7
JournalEarth, Planets and Space
Volume56
Issue number12
Publication statusPublished - 2004
Externally publishedYes

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Keywords

  • Active fault
  • Central Japan
  • Crustal structure
  • Geologic structure
  • Itoigawa-Shizuoka tectonic line
  • Northern Fossa Magna
  • Seismic reflection profile
  • Seismic refraction profile

ASJC Scopus subject areas

  • Earth and Planetary Sciences (miscellaneous)

Cite this

Sato, H., Iwasaki, T., Ikeda, Y., Takeda, T., Matsuta, N., Imai, T., Kurashimo, E., Hirata, N., Sakai, S., Elouai, D., Kawanaka, T., Kawasaki, S., Abe, S., Kozawa, T., Ikawa, T., Arai, Y., & Kato, N. (2004). Seismological and geological characterization of the crust in the southern part of northern Fossa Magna, central Japan. Earth, Planets and Space, 56(12), 1253-1259.