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Fig. 8 | Earth, Planets and Space

Fig. 8

From: Monitoring the instrument response of the high-sensitivity seismograph network in Japan (Hi-net): effects of response changes on seismic interferometry analysis

Fig. 8

Time series of interferometry and instrument response. a Time delay between the reference ACF and the ACFs on (a1) 30 October 2010 and (a2) 30 October 2011. Error bars indicate the 95 % confidence interval calculated by the bootstrap method using ACFs spanning 1 week. b Fractional velocity change (dv/v %) at the N.KMIH station obtained from ACFs with lag times from 4 to 15 s. The gray zone indicates apparent velocity changes within ±0.1 %, which may be caused by the changes in instrument response caused by the 2011 Tohoku-Oki earthquake. c Monitoring results of the Hi-net vertical seismogram at the N.KMIH station from 2008 to 2013. The blue and green inverted triangles are the natural frequency f and the damping constant h, respectively

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