Distribution of quaternary volcanoes in the Northeast Japan arc: Geologic and geophysical evidence of hot fingers in the mantle wedge

Yoshihiko Tamura, Yoshiyuki Tatsumi, Dapeng Zhao, Yukari Kido, Hiroshi Shukuno

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)

Abstract

Clustering of volcanic centers, low-velocity regions in the mantle wedge and local negative Bouguer gravity anomalies along the rear of the volcanic arc are closely correlated in Northeast Japan. These observations may be best explained by the presence of inclined, finger-like, hot regions in the mantle wedge of the subduction zone. These fingers, perpendicular to the arc-trench system in the Northeast Japan arc, have an average separation of ∼80 km and an average width of 50 km. Each of ten fingers extends from the deep mantle (>150 km) below the back-arc region toward the shallower mantle (∼50 km) beneath the volcanic front. Quaternary volcanoes are built immediately above the hot mantle fingers. Volcanic basements are uplifted by repeated injection of magmas into the crust, accompanied by Quaternary volcanic activity on the surface. Although volcanic activity is rare along the Japan Sea coast, the hot mantle fingers exist within the mantle wedge as evidenced by tomographic results. The negative Bouguer anomalies at the rear of the volcanic arc could be caused by magmas supplied from the hot mantle fingers, which have not yet been erupted, but may have accumulated at the Moho discontinuity.

Original languageEnglish
Pages (from-to)135-139
Number of pages5
JournalProceedings of the Japan Academy Series B: Physical and Biological Sciences
Volume77
Issue number7
DOIs
Publication statusPublished - 2001 Sep
Externally publishedYes

Keywords

  • Mantle wedge
  • Quaternary volcano
  • Subduction zone
  • Volcano spacing

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Physics and Astronomy(all)

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