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Seismic Velocity Changes in the Backarc Continental Crust After the 2011 M w 9.0 Tohoku‐Oki Megathrust Earthquake
Author(s) -
Hong TaeKyung,
Lee Junhyung,
Chi Donggeun,
Park Seongjun
Publication year - 2017
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2017gl075447
Subject(s) - geology , seismology , rayleigh wave , crust , intraplate earthquake , seismic wave , epicenter , geophysics , surface wave , tectonics , telecommunications , computer science
The 2011 M w 9.0 Tohoku‐Oki megathrust earthquake accompanied coseismic and postseismic displacements around the eastern Eurasian continental plate. Noise cross correlations produced transient seismic waveforms along interstation paths in the Korean Peninsula. We measured the traveltime changes of the fundamental mode Rayleigh waves over the range of 0.03–0.08 Hz after the megathrust earthquake. The temporal seismic velocity changes in the lower crust were assessed from the traveltime changes. The traveltimes increased instantly after the megathrust earthquake and were gradually recovered over several hundreds to thousands of days. The instant shear wave velocity decreases ranged between 0.731 (±0.057)% and 4.068 (±0.173)%. The temporal medium perturbation might be caused by the transient uniaxial tensional stress due to the coseismic and postseismic displacements. The medium properties may be recovered by progressive stress field reconstruction.