3D Lava flow mapping of the 17–25 May 2016 Etna eruption using tri-stereo optical satellite data

Gaetana Ganci,Giuseppe Bilotta,Vito Zago,Ciro Del Negro,Annalisa Cappello,Alexis Herault

doi:10.4401/ag-7875

Gaetana Ganci, Giuseppe Bilotta + Show 4 more

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https://doi.org/10.4401/ag-7875

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Abstract

During basaltic eruptions, the average rate at which lava is erupted (effusion rate) is one of the most important factor controlling the evolution, growth and extent of the flow field. This has implication both for forecasting purposes as input parameter into physics-based numerical models, and for advancing knowledge on the shallow feeder system by constraining the mass supplied. Satellite remote sensing provides a means to estimate the average effusion rate by applying a direct conversion from the measured radiant heat loss by an active lava flow. This conversion relies on a set of parameters of lava (e.g. rock density, heat capacity, vesicularity, emissivity, etc.) and suffers of multiple sources of uncertainties and measurements errors, whose quantification is still an open problem. Here we constrain the lava volume emitted at Mt Etna on 17-25 May 2016, by using pre-eruptive and post eruptive digital elevation models (DEMs) obtained processing satellite images acquired by the Pleiades constellation, which provides images at 50 cm resolution in stereo and tri-stereo mode. The 3D processing of the tri-stereo Pleiades imagery (acquired on 24 December 2015 and 18 July 2016), performed using the free and open source MicMac photogrammetric library provides estimations of the distribution of thickness and the bulk volume emitted. The integration of multi-platform remote sensing products represents a new potential of merging capabilities to enable a more comprehensive response to effusive crises.

Highlights

Mount Etna is one of the most active and hazardous volcanoes in the world, well known for the persistent activity from the summit craters and frequent lava flow-forming eruptions from vents situated on the flanks of the volcano [Cappello et al, 2013; Acocella et al, 2016]
We estimated the distribution of thickness, areas and volumes (Table 1) in correspondence of the flows emplaced during the 18-19 and 22-25 May eruptive episodes occurred at BN and VOR, and the flow emitted on 18-19 May by the eruptive vent opened at the eastern base of the North-East Crater (NEC), near the JulyAugust 2014 cones
We found that the thickness distribution of flow b is in good agreement with typical field measurements related to the small lava flows emplaced on Valle del Bove [Behncke et al, 2014]

Summary

Introduction

Mount Etna is one of the most active and hazardous volcanoes in the world, well known for the persistent activity from the summit craters and frequent lava flow-forming eruptions from vents situated on the flanks of the volcano [Cappello et al, 2013; Acocella et al, 2016]. On the evening of May 17, 2016 an intense Strombolian activity started at the North-East Crater (NEC), followed by the emission of volcanic ash This eruptive activity ended the following day, when the Voragine (VOR) began to erupt, producing a pulsating lava fountain and a small lava flow from the western rim of the Voragine-Bocca Nuova depression (Figure 1). On 18 May, a new eruptive vent opened at the eastern base of the NEC, near the two cones that formed during the July-August 2014 activity, which fed a lava flow that expanded towards the northern wall of Valle del Bove. This lava flow remained active until the early

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