Fig. 7From: Determination of temporal changes in seismic velocity caused by volcanic activity in and around Hakone volcano, central Japan, using ambient seismic noise recordsDependence of the time shift dt on the lag time t in ACFs. a, b Lag time and time dependence of the relative ACF phase delay at the KOM and OWD stations. Time shifts dt were measured by the cross-correlation of the reference ACF and each ACF with a time window of 1.5 s. If the maximum correlation coefficient was less than 0.6, the time shift value was excluded; these values are shaded gray. Time shift as a function of lag time t c at the KOM station on 26 March 2011 (immediately after the 2011 Tohoku-oki earthquake), d at the KOM station on 20 May 2013, and e at the OWD station on 20 February 2013 (during the 2013 swarm activity). Only dt values with cross-correlation coefficients of 0.6 or greater and standard deviations dt of less than 0.05 s are plottedBack to article page