Periodic measurement of in-situ rock stress at shallow depth in the vicinity of the epicenter before and after the 2011 tohoku-oki earthquake

Kiyotoshi Sakaguchi, Motoki Egawa, Tatsuya Yokoyama

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

In-situ rock stress measurement was carried out in the Kamaishi mine of lwate prefecture to quantify the variation of the shallow crustal stress field associated with the 2011 Tohoku-oki earthquake. Stress measurement was conducted by the Compact Conical-ended Borehole Overcoring (CCBO) technique. Measurement period is from 1991 to 2015. Main results obtained in this study can be summarized as follows. The magnitudes of the three-dimensional principal stresses and the vertical stress at one year after the earthquake were more than double those before the earthquake. The principal stress magnitudes measured at two and three years after the earthquake decreased relative to those at one year after the earthquake. The increasing and decreasing trends in crustal stress in the Kamaishi mine can be interpreted in terms of the effects of coseismic rupture behavior of the Tohoku-oki earthquake mainshock and the occurrence of aftershocks in the Sanriku-oki low-seismicity region (SLSR), where the Kamaishi mine is located. The consistency between the change in measured stress and the change in seismicity in the Kamaishi regions suggests that the results of stress measurements, even those at a much shallower depth than the earthquake source fault, can be useful for understanding rupture propagation behavior.

Original languageEnglish
Title of host publicationISRM International Symposium on In-Situ Rock Stress, ISRS 2016
Editors Raasakka, Erik Johansson
PublisherInternational Society for Rock Mechanics
Pages510-519
Number of pages10
ISBN (Electronic)9789517586061
Publication statusPublished - 2016
EventISRM 7th International Symposium on In-Situ Rock Stress, ISRS 2016 - Tampere, Finland
Duration: 2016 May 102016 May 12

Publication series

NameISRM International Symposium on In-Situ Rock Stress, ISRS 2016
Volume2016-May

Other

OtherISRM 7th International Symposium on In-Situ Rock Stress, ISRS 2016
CountryFinland
CityTampere
Period16/5/1016/5/12

Keywords

  • CCBO technique
  • Earthquake
  • In-situ rock stress
  • Rock stress measurement

ASJC Scopus subject areas

  • Geophysics

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