Fig. 3

An example of the impulse response of Proc. V. a Impulsive time series \(\varvec{\delta}^{j} = \left( {\delta_{i}^{j} } \right)_{i = 1\sim N}\) (black) and deconvolved impulse \(\varvec{h}^{j} = \left( {h_{i}^{j} } \right)_{i = 1\sim N}\) (red). Here, the instrument response of the FUK broadband seismometer was deconvolved using the “transfer” command of SAC. b Impulsive time series \(\varvec{\delta}^{j} = \left( {\delta_{i}^{j} } \right)_{i = 1\sim N}\) (black) and deconvolved and 0.002–0.03-Hz band-pass-filtered impulse \(\varvec{g}^{j} = \left( {g_{i}^{j} } \right)_{i = 1\sim N}\) (red)