Seismicity associated with eruptive activity at Langila volcano, Papua New Guinea

Abstract

Abstract During periods of eruptive activity at Langila Volcano, various combinations of low-frequency earthquakes and high-frequency air waves have been recorded, ranging from earthquakes alone to air waves alone. It is shown that these different types of events are part of a continuous range of events which are all interpreted to be explosions at or near the summit. Continuous tremor is also often recorded for durations of several minutes to hours and is classified into two types: “harmonic” and “non-harmonic”. Spectral analysis shows that the “non-harmonic” tremor resembles a string of low-frequency events. In contrast, the spectra of “harmonic” tremor show simple modal characteristics which indicate some type of resonating source. This source is thought to include a gas-filled cavity above the magma body within the volcano.