Volcanic hazard monitoring at the Mount Etna during the eruption on Christmas Eve 2018
Abstract
On 24 December 2018, Mount Etna erupted from a fissure that opened on the high south-eastern flank inside the uninhabited Valle del Bove. The eruption lasted only three days, and was modest both for the volumes of lava erupted (3-4 million m3) and for the area covered by the lava (less than 1 km2), but it was accompanied by strong ash emissions, which had earlier covered nearby villages and Catania airport had to temporarily suspend operations, and an intense seismicity culminated with the earthquake of 26 December (magnitude ML = 4.8) on the south-eastern side of Etna, which damaged buildings in nearby villages. After the end of the eruption, seismic activity continued, albeit gradually decreasing. The last significant earthquake, an event of magnitude ML = 4.1, took place on 8 January 2019 on the north-eastern side of Etna. At the time, the volcanic unrest at Etna and seismic activation along main faults around the volcano were a significant concern for civil authorities. They were worried about risks to populations if an effusive eruption disaster took place, and needed to plan to respond to ensure safety. It was in this context that we evaluated volcanic hazards with the intent to provide scrupulous and timely information such that civil authorities can better decide how to protect life and property. The fact that the typology of an imminent eruption is almost indeterminate and it cannot be predicted by the precursory activity makes any effective risk mitigation action during a volcanic crisis particularly difficult. Thus, accurate eruption forecasting needs to be based on a combination of previously acquired long-term hazard assessment and real-time volcano monitoring data. Here we use a three-step approach to produce different scenarios as eruptive conditions change. We firstly analyze the geophysical monitoring data to establish the more probable area of future vent opening. Successively we use geological and historical records on past activity to classify the expected eruptions. Finally we assess the hazard posed by effusive eruption by modeling the probability of lava flow inundation into affected areas. This approach outlines the way in which the emerging evidence and data about the unrest, which are uncertain and time-varying, can be queried to provide provisional eruption probability estimates for decision support.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.V23I0310D
- Keywords:
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- 3275 Uncertainty quantification;
- MATHEMATICAL GEOPHYSICS;
- 8419 Volcano monitoring;
- VOLCANOLOGY;
- 8488 Volcanic hazards and risks;
- VOLCANOLOGY;
- 8494 Instruments and techniques;
- VOLCANOLOGY