Effusion Rates on Mt. Etna and Their Influence on Lava Flow Hazard Assessment

Francesco Zuccarello,Giuseppe Bilotta,Gaetana Ganci,Annalisa Cappello

doi:10.3390/rs14061366

Francesco Zuccarello, Giuseppe Bilotta + Show 2 more

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https://doi.org/10.3390/rs14061366

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Journal: Remote sensing	Publication Date: Mar 11, 2022
Citations: 9	License type: CC BY 4.0

Affiliation: Istituto Nazionale di Geofisica e Vulcanologia

Abstract

The rate at which lava is discharged plays a key role in controlling the distance covered by lava flows from eruptive vents. We investigate the available time-averaged discharge rates (TADRs) estimated for recent flank eruptions at Mt. Etna volcano (Italy), in order to define a possible generalized effusion rate trend which is consistent with observed real data. Our analysis indicates a rapid waxing phase in which effusion rate peaks occur for between 0.5 and 29% of the total eruption time, followed by a progressive decrease in the waning phase. Three generalized curves are built by calculating the 25th, 50th and 75th percentiles values associated with the occurrence of effusion peaks, and with the slope variations of descending curves in the waning phase. The obtained curves are used as an input for the GPUFLOW model in order to perform numerical simulations of the lava flows paths on inclined planes, and are compared with those generated by using effusion rate curves with a bell-shaped time-distribution. Our tests show how these characteristic curves could impact single-vent scenarios, as well as short- and long-term hazard maps, with maximum variations of up to 40% for a specific category of eruptive events.

Highlights

Lava flows are recurring and widespread hazards affecting areas around active volcanoes, which can cause significant social and economic loss
Greater lengths of lava flows are correlated with high lava effusion rates [11,12], and at basaltic volcanoes lava discharge occurs at high rates during the early phases of eruptions, followed by a slow decrease towards the end [13,14]
The incidence of the effusion rate peaks at the beginning of the eruptions reflects that more than 50% of the lava volume erupts in the first 10–40% of the total duration, followed by an overall decrease in the discharge rates

Summary

Introduction

Lava flows are recurring and widespread hazards affecting areas around active volcanoes, which can cause significant social and economic loss. Advances in the knowledge of the physical parameters controlling the evolution of flowing lava allowed the development of physics-based models of lava flows, which have been proven to be effective to forecast and assess the hazard posed by effusive events (e.g., [1–4]) Such numerical simulations can be adopted for real-time applications by forecasting in a few minutes the expected path that flowing lava could cover in days or weeks during an ongoing eruption [5–8]. Greater lengths of lava flows are correlated with high lava effusion rates [11,12], and at basaltic volcanoes lava discharge occurs at high rates during the early phases of eruptions, followed by a slow decrease towards the end [13,14] Both for the assessment of long-term hazards and for monitoring efforts during on-going eruptions, the effusion rate is assumed to be constant or to have a bell-shaped time-dependent behavior [10,15]

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