[SVC38-P33] Relationship between duration of eruption tremor and eruption volume
We calculated the envelope width (p) using the estimated values of As and Is and investigated the relation between p and Is. p is defined as Is/As and can be used as a parameter of duration (T) of a seismic envelope waveform (Kumagai et al., JGR, 2018). We found that p is proportional to 0.4 power of Is. We also found that envelope waveforms of eruption tremors in 5–10 Hz have the following features; the amplitudes of envelope waveforms gradually increase, remain roughly constant during a certain period, and gradually decrease to the noise level. Moreover, p tends to increase with As. These envelope waveforms can be approximated as trapezoids, where As and T correspond to their height and lower base, respectively. We found that the ratios of upper to lower bases for these envelope waveforms are roughly constant. In this case, the proportionality between p and T holds. Based on the relation between eruption rate and As, eruption volume (V) is proportional to Is. Therefore, the relation between p and Is as shown above indicates that T is proportional to 0.4 power of V. We found that this proportional relation is consistent with the estimates of T and V for various Plinian eruptions compiled by Mastin et al. (JVGR, 2009). This indicates that the scaling relation between duration of eruption tremor and eruption volume in Plinian eruptions holds over a wide range of eruption size.