Fig. 3

Acoustic waveform data for both acoustic stations for the 27 April 2016 eruption on Whakaari. A Non-filtered raw sensor reading for WIZ showing the increasingly larger down pressures from the rarefaction of the eruption pulses as the acoustic wave passes the station. B Filtered acoustic data between 0.5 and 10 Hz, C spectrogram for WIZ, D non-filtered raw sensor reading for WSRZ, E filtered acoustic data between 0.5 and 10 Hz for WSRZ, F eruption spectrogram for WSRZ. A1 and D1 are the spectra for WIZ and WSRZ respectively