The Duration Amplitude Distribution of Volcanic Tremor Recorded at Ijen Volcano, Indonesia

Abstract

This research was conducted with the aim of explaining the physical processes that occur at the source. The duration-amplitude distribution is an amplitude scaling method that can describe the process of sustained earthquake sources such as volcanic tremors. The data used in this study are seismic data from Mount Ijen for the period from January to March 2012 and January to March 2014. Scaling the duration amplitude distribution is done by converting the amplitude to reduced displacement (DR). The cumulative duration is calculated with a range of 3-12 cm2 which is the lowest and highest reduced displacement values. The cumulative duration plot results are then adjusted to the power law model and the exponential model. a correlation coefficient (R2) was calculated to evaluate the fit for each of these models. The results showed that the R2 exponential model was higher than the R2 power law model for all events in both 2012 and 2014 and there was no transition between the two models. This indicates that the source process of the Ijen volcano volcanic tremor is related to the scale-bound source process and there was no source change in either 2012 or 2014. However, differences in amplitude characteristics were found in 2012 and 2014. The volcanic tremors in 2012 were stronger than those in 2014, according with the reality of changing the condition of the crater lake which is stronger in 2012. Volcanic tremors and changes in the Ijen crater lake are important for forecasting the eruption of the Ijen volcano.