Articles | Volume 15, issue 3
Research article
27 Mar 2015
Research article |  | 27 Mar 2015

Estimation of three-dimensional crustal movements in the 2011 Tohoku-Oki, Japan, earthquake from TerraSAR-X intensity images

W. Liu, F. Yamazaki, M. Matsuoka, T. Nonaka, and T. Sasagawa

Abstract. The Tohoku-Oki earthquake on 11 March 2011 caused significant widespread crustal movements. In a previous study, we proposed a method for capturing two-dimensional (2-D) surface displacements from a pair of pre- and post-event TerraSAR-X (TSX) intensity images. However, it is impossible to detect three-dimensional (3-D) displacements from one pair of TSX images. In this study, three pairs of pre- and post-event TSX images taken on different paths were used to estimate 3-D crustal movements. The relationship between the actual 3-D displacements and the converted 2-D movements in the synthetic-aperture radar (SAR) images was derived based on the observation model of a SAR sensor. The 3-D movements were then calculated from three sets of detected 2-D movements that occurred within a short time period. Compared with GPS observations, the proposed method was found to be capable of detecting the 3-D crustal movements with sub-pixel accuracy.

Short summary
The method for capturing two-dimensional surface displacements was applied to three pairs of pre- and post-event high-resolution TerraSAR-X intensity images of the 2011 Tohoku-Oki earthquake taken in ascending and descending paths, and the results were used for estimating the actual three-dimensional movements. Compared with the GPS data at three ground-control stations, the estimation errors in the horizontal and vertical directions were less than 0.3 m in spite of the pixels size (1.25 m).
Final-revised paper