Influence of crustal lithology and the thermal state on microseismicity in the Wakayama region, southern Honshu, Japan

Sumire Maeda, Shinji Toda, Toru Matsuzawa, Makoto Otsubo, Takumi Matsumoto

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)

Abstract

Here we investigate the influence of the lithology and thermal state of the upper crust on earthquake distributions beneath the Wakayama region, southern Honshu, Japan, to better understand the influence of crustal conditions on regional seismogenesis. The earthquakes are concentrated in the deeper sections of mafic belts and shallower sections of pelitic belts, based on a comparison of relocated hypocenters and estimated subsurface geological structures. We compare the frictional properties of pelitic rocks and basalt, as obtained from petrological experiments, with the hypocenter depth distributions in pelitic and mafic belts to assess the control of crustal lithology on the depth extent of regional seismicity. The earthquake distributions are consistent with the temperature ranges over which the respective rock types are expected to exhibit a velocity-weakening behavior, based on the petrological experiments. The results suggest that the occurrence of shallow intraplate earthquakes is controlled by the temperature- and lithology-dependent friction of the upper crust. [Figure not available: see fulltext.]

Original languageEnglish
Article number173
Journalearth, planets and space
Volume73
Issue number1
DOIs
Publication statusPublished - 2021 Dec

Keywords

  • Geological structure
  • Kii Peninsula
  • Lithological heterogeneity
  • Lithospheric thermal structure
  • Seismicity
  • Seismogenic depth

ASJC Scopus subject areas

  • Geology
  • Space and Planetary Science

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