Identification of Far-Field Long-Period Ground Motions Using Phase Derivatives

Figure 9

Five samples of false positive records; the red dashed lines shown in velocity-time histories mark the truncated waves, which are determined on the basis of envelope delays. The former three records (a)–(c) were recorded from Tohuku aftershock, M7.7, and the latter two records (d, e) were from Tohuku, M9.

(a)

(b)

(c)

(d)

(e)