How do temporal patterns in volcanic seismicity relate to the dynamics between volcanic processes at Mt Etna?

Volcanic seismicity is a powerful indicator of activity at volcanoes worldwide, providing information on volcanic structures and subsurface processes such as magmatic fluid transport. Volcanic systems produce a range of eruptive styles and durations; determining whether future eruptions will be explosive or effusive is key for reducing the hazards faced by local communities. Mt. Etna is the largest volcano in Europe and is continuously monitored by a substantial seismic network providing an ideal location to quantitatively constrain links between eruptive styles and seismicity.

During periods of intense volcanic activity, many seismic events will go undetected. A matched filter search identifies repeats of template events, including those which are hidden behind the noise, and can increase a seismic catalogue by a factor of 10. Additionally, it categorises seismic events into families of similar waveforms, implying shared source characteristics and locations. This establishes a framework for investigating how seismic sources evolve that can be linked to subsurface processes and structures, providing a quantitative comparison with the vast and complex eruptive history of Mt. Etna.

Here we focus on the December 2018 flank eruption at Mt Etna, using template events from INGV’s seismic catalogue for a matched filter search across four years of continuous data. We investigate spatial, temporal and waveform trends of individual families, to track how the seismic signal evolves over time - providing a quantitative framework to interpret subsurface processes and eruptive styles at Mt. Etna. Initial results highlight several families that are triggered during different stages of the eruption, coincident with variations seen in GPS and gas emissions during this time frame. This categorisation of seismicity allows finer details to be unveiled that were previously not seen in the original seismic catalogue.