Fig. 6

Example of a 1-min waveform record from each station, taken during the volcanic tremor. Black traces indicate the vertical components of velocity waveforms for the period 2:32:20–2:33:20 on July 1, 2015, to which a band-pass filter between 2 and 6 Hz has been applied. Red traces indicate three-component RMS envelopes for the band-passed signals