Fig. 3.
From: Spatio-temporal occurrence patterns among the foreshocks preceding the 2007 Noto Hanto earthquake
Time series of cross-correlation coefficients averaged among the three components for the reference events (a) E2, (b) E3, (c) E4, (d) E5, (e) E6, and (f) E8 during the 25-day period leading up to the mainshock. The bottom panel (g) represents a segment of (f) magnified for the last hour prior to the mainshock. The dashed lines denote the correlation threshold of 0.6. Gray circles denote events whose cross-correlation coefficients are higher for other clusters.