Analyses of explosion earthquakes at Sinabung Volcano: characteristics of waveform, spectra, and energy

Abstract

Abstract The characteristic of explosion earthquakes associated with lava avalanche at Sinabung volcano from October to December 2014 is investigated. The 1-component short-period seismometers which are Sukanalu (SKN), Laukawar (KWR), and Kebayaken (KBY) are used. All stations are located about 3-9 km away from the summit. The result shows the characteristics of these waveforms as follows; the amplitude increases rapidly to maximum for about 2-5 s, then the amplitude is almost constant for about 30-40 s followed by the gradual decrease of amplitude for about 40-50 s. Most of explosion earthquakes have a dominant frequency at about 1-4 Hz. The result also observed that the energy of explosion earthquake changes with lapse time and much stable for longer duration compared with explosion earthquake study at different volcano. Our result suggests that the explosion earthquake at Sinabung volcano may have a different waveform generation and/or mechanism to the general explosion earthquake at different volcano.