Heterogeneous stress state of island arc crust in northeastern Japan affected by hot mantle fingers

Bunichiro Shibazaki, Tomomi Okada, Jun Muto, Takumi Matsumoto, Takeyoshi Yoshida, Keisuke Yoshida

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)

Abstract

By considering a thermal structure based on dense geothermal observations, we model the stress state of the crust beneath the northeastern Japan island arc under a compressional tectonic regime using a finite element method with viscoelasticity and elastoplasticity. We consider a three-layer structure (upper crust, lower crust, and uppermost mantle) to define flow properties. Numerical results show that the brittle-viscous transition becomes shallower beneath the Ou Backbone Range compared with areas near the margins of the Pacific Ocean and the Japan Sea. Moreover, several elongate regions with a shallow brittle-viscous transition are oriented transverse to the arc, and these regions correspond to hot fingers (i.e., high-temperature regions in the mantle wedge). The stress level is low in these regions due to viscous deformation. Areas of seismicity roughly correspond to zones of stress accumulation where many intraplate earthquakes occur. Our model produces regions with high uplift rates that largely coincide with regions of high elevation (e.g., the Ou Backbone Range). The stress state, fault development, and uplift around the Ou Backbone Range can all be explained by our model. The results also suggest the existence of low-viscosity regions corresponding to hot fingers in the island arc crust. These low-viscosity regions have possibly affected viscous relaxation processes following the 2011 Tohoku-oki earthquake.

Original languageEnglish
Pages (from-to)3099-3117
Number of pages19
JournalJournal of Geophysical Research: Solid Earth
Volume121
Issue number4
DOIs
Publication statusPublished - 2016 Apr 1

Keywords

  • finite element modeling
  • hot mantle fingers
  • intraplate earthquakes
  • island arc crust of northeastern Japan
  • stress state

ASJC Scopus subject areas

  • Geophysics
  • Geochemistry and Petrology
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science

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