Complementary Use of DAS and Seismometers for Seismo-Volcanic Event Classification at Mt.Etna

Seismic monitoring in volcanic environments is crucial for hazard assessment and eruption forecasting. In this context, the use of Distributed Acoustic Sensing (DAS) as a complementary acquisition system to conventional seismometers represents a promising approach for seismo-volcanic event analysis and classification.

During the summer of 2019, Etna exhibited a variety of seismo-volcanic signals that were simultaneously recorded by two different acquisition systems: a broadband array of 26 sensors deployed at Piano delle Concazze and a 1.5 km-long fiber-optic cable interrogated by a DAS device installed in the Pizzi Deneri Observatory. The recorded dataset includes different types of events, such as volcano-tectonic (VT) earthquakes, as well as long-period (LP), very-long-period (VLP) events, and volcanic explosions.

In this study, we present a comparative analysis between conventional seismic data and DAS recordings, with the aim of evaluating the consistency and reliability of event classification between the two systems. While traditional seismometers offer greater accuracy in signal fidelity, DAS measurements provide high spatial resolution, allowing for detailed observation of signal variability along the fiber.

The analysis focuses on the comparison of waveform characteristics and frequency content across the two datasets.

Event classification provides key insights into underlying physical processes, such as rock fracturing and fluid migration within the volcano edifice, and enables tracking of the temporal evolution of volcanic activity, basically contributing to improved hazard assessment and monitoring strategies.