Seismo-acoustic characterisation of the 2018 Ambae (Manaro Voui) eruption, Vanuatu

Abstract A new episode of unrest and phreatic/phreatomagmatic/magmatic eruptions occurred at Ambae volcano, Vanuatu, in 2017–2018. We installed a multi-station seismo-acoustic network consisting seven 3-component broadband seismic stations four 3-element (26–62 m maximum inter-element separation) infrasound arrays during the last phase 2018 eruption episode, capturing least six reported major explosions towards end episode. The observed volcanic signals are generally passband 0.5–10 Hz eruptive activity, but corresponding acoustic have relatively low frequencies (< 1 Hz). Apparent very-long-period 0.2 Hz) also we show that they generated as ground-coupled airwaves propagate with atmospheric velocity. observe strongly coherent waves all eruptions. Using waveform similarity signals, detect previously unreported summit vent region based on constant-celerity reverse-time-migration (RTM) analysis. detected bursts temporally related to shallow tremor (frequency content 5–10 Hz), which characterise using simplified amplitude ratio method station pair different distances from vent. increased onset large then decreased, is interpreted source ascent descent. change potentially useful recognise only two quickly. This study reiterates value joint data for improving interpretation activity reducing ambiguity geophysical monitoring.