Fig. 2

Robustness of the V17 data processing illustrated for two stations of the F-net network. FUK (top) and INN (bottom) are STS1 and STS2 sensors, respectively. For each sensor, the curves show the obtained vertical acceleration signals for different choices of the original time window. These choices can be read in the name given to each curve: the negative number following “OT” gives the starting time (in s) of the window relative to the Tohoku earthquake origin time; the negative number following “TP” gives the ending time (in s) of the window relative to the P-wave arrival time at each station. No differences can be observed in the resulting accelerations in the 0.002–0.03 Hz frequency band