Bubble dynamics during volcanic eruptions: in situ measurements and modelling of physical processes of a rising and exploding gas slug

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During the initial two years funding of this research we collected a 16 days long multidisciplinary data set at Yasur volcano, Vanuatu, that includes seismological and acoustic data, infrared video footage, as well as Doppler radar measurements to quantify eruption dynamics, and DOAS measurements for SO2 flux estimation. During this time a total of about 26000 eruptions were observed and initial data processing indicated a transition in eruption style from explosive nearly ash free eruptions to very ash rich plumes and back to nearly ash free eruptions. In the frame of this proposal we will explore the physics behind this change in eruption style using our multidisciplinary data set. In particular we will combine the processed seismic and acoustic data with the radar data to verify which vent of Yasur volcano was active and determine at what depth below the vent exit the magma level in the conduit is located. Exploiting the radar data we will determine the kinetic energy released during each single explosion and from that determine either bubble overpressure or gas slug volume, while the acoustic and seismic data will give us evidences for the seismic and acoustic energy release. This will lead to a more complete understanding of the energy budget at an active volcano. The radar data will also allow us to define different eruption types and using a neuronal network we will then classify all recorded events. These different processing steps will help to improve current models for eruption dynamics.