Fig. 4

Spatial distribution and crack orientation dependence of the residuals between observed and synthetic waveforms. The residuals E are calculated by Eq. (2). Results of the three grid searches are overlain. The second and third search domains are represented by the solid outlines. The crack orientation dependence is plotted against the crack normal direction projected onto the upper hemisphere. Triangles and stars are the station locations and the best-fit solution of the final search, respectively. Gray lines are the topographic contours (interval 200 m)