Orientations of best-fit σ 1 and σ 3 axes. (a) A uniform stress field across the entire study area and (b) 20 subareas divided along and across the fault strike, shown by black lines. σ 1 and σ 3 axes are indicated by red and blue arrows, respectively, at the centroid of events used for the inversions. The length of the arrows indicates the relative plunge of the axes. P-axis orientations are also shown by bars. The length and color (scale is shown at the right) of a bar corresponds to the plunge and azimuth of the P-axes, respectively.