Acceleration of regional plate subduction beneath Kanto, Japan, after the 2011 Tohoku-oki earthquake

Naoki Uchida, Youichi Asano, Akira Hasegawa

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)

Abstract

Two oceanic plates (the Pacific (PA) and Philippine Sea (PH)) subduct beneath the land plate, and they forms deeper (PH-PA) and shallower (land-PH) plate boundaries beneath Kanto. Remarkably enhanced seismicity was observed in the densely populated area after the 2011 Tohoku-oki earthquake, which cannot simply be explained by the southern expansion of the postseismic slip of the earthquake. We examine interplate repeating earthquakes to constrain the relative plate motion across aseismically slipping faults. The repeater slip rates show creep rates in the deeper and shallower boundaries, respectively, increased to 2.4–6.6 times and 1.3–6.2 times the pre-Tohoku-oki rates. In addition, the repeater slip directions show no change larger than 4° in the deeper boundary. The interplate creep rates and slip directions suggest that regional movements of both the two plates had accelerated. They probably caused the seismicity increase, frequent slow slips on the shallower boundary, and enhanced probability of larger earthquakes.

Original languageEnglish
Pages (from-to)9002-9008
Number of pages7
JournalGeophysical Research Letters
Volume43
Issue number17
DOIs
Publication statusPublished - 2016 Sep 16

Keywords

  • Kanto earthquake
  • Philippine Sea plate
  • Tohoku-oki earthquake
  • aseismic slip
  • plate motion
  • repeating earthquake

ASJC Scopus subject areas

  • Geophysics
  • Earth and Planetary Sciences(all)

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