Investigation on the postseismic deformation associated with the 2011 tohoku earthquake based on terrestrial and seafloor geodetic observations: To evaluate the further seismic hazard potential on the plate interface beneath the northeastern Japanese islands

Takeshi Iinuma, Ryota Hino, Motoyuki Kido, Yukihito Osada, Daisuke Inazu, Yoshihiro Ito, Syuichi Suzuki, Yusaku Ohta, Hiromi Fujimoto

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

5 Citations (Scopus)

Abstract

The 2011 Tohoku Earthquake (M9.0), which occurred on the plate boundary between the subducting Pacific plate and continental plate has been associated with postseismic deformation, including aseismic slip at the plate interface (postseismic slip). In order to evaluate the potential for further seismic activity, we investigated the spatial and temporal evolution of the postseismic slip based not only on terrestrial GPS data but also on seafloor geodetic data. We estimated the displacements due to the postseismic slip by subtracting the displacements due to large aftershocks and viscoelastic relaxation from the original displacement time series data and used a time-dependent inversion method to estimate the postseismic slip distributions. The resultant postseismic slip distributions depend strongly on the assumed value of the viscosity. However, the following two features are independent of the viscosity assumption: (1) large postseismic slip has been occurring at a very shallow (≤ 20km in depth) portion of the plate interface south of the area of huge coseismic slip and (2) significant postseismic slip has occurred at a deep (approximately 50 km in depth) portion of the plate interface. The results suggest that the elastic strain and the stress concentrated at the plate interface at a depth of approximately 30 km in the segment off the Boso Peninsula have not yet been released and continue to generate large aftershocks.

Original languageEnglish
Title of host publicationIAG 150 Years - Proceedings of the 2013 IAG Scientific Assembly
EditorsChris Rizos, Pascal Willis
PublisherSpringer Verlag
Pages459-466
Number of pages8
ISBN (Print)9783319246031
DOIs
Publication statusPublished - 2016
Event150th Anniversary with a Scientific Assembly, IAG 2013 - Potsdam, Germany
Duration: 2013 Sep 22013 Sep 6

Publication series

NameInternational Association of Geodesy Symposia
Volume0
ISSN (Print)0939-9585

Other

Other150th Anniversary with a Scientific Assembly, IAG 2013
Country/TerritoryGermany
CityPotsdam
Period13/9/213/9/6

Keywords

  • GPS
  • Interplate coupling
  • Postseismic deformation
  • Postseismic slip
  • Seafloor geodesy
  • Viscoelastic relaxation

ASJC Scopus subject areas

  • Computers in Earth Sciences
  • Geophysics

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