The Monitoring of CO2 Soil Degassing as Indicator of Increasing Volcanic Activity: The Paroxysmal Activity at Stromboli Volcano in 2019–2021

Lorenzo Calderone,Marianna Cangemi,Claudio Inguaggiato,Fabio Vita,Salvatore Inguaggiato

doi:10.3390/geosciences11040169

Abstract

Since 2016, Stromboli volcano has shown an increase of both frequency and energy of the volcanic activity; two strong paroxysms occurred on 3 July and 28 August 2019. The paroxysms were followed by a series of major explosions, which culminated on January 2021 with magma overflows and lava flows along the Sciara del Fuoco. This activity was monitored by the soil CO2 flux network of Istituto Nazionale di Geofisica e Vulcanologia (INGV), which highlighted significant changes before the paroxysmal activity. The CO2 flux started to increase in 2006, following a long-lasting positive trend, interrupted by short-lived high amplitude transients in 2016–2018 and 2018–2019. This increasing trend was recorded both in the summit and peripheral degassing areas of Stromboli, indicating that the magmatic gas release affected the whole volcanic edifice. These results suggest that Stromboli volcano is in a new critical phase, characterized by a great amount of volatiles exsolved by the shallow plumbing system, which could generate other energetic paroxysms in the future.

Highlights

The area of Pizzo Sopra La Fossa, in the summit area of Stromboli Island (Figure 1), is characterized by an anomalous soil degassing with areal CO2 fluxes ranging between
The STR02 soil CO2 flux monitoring station was installed at Pizzo Sopra La Fossa in 1999 and produced a large and unique dataset of continuous soil CO2 degassing
The paroxysmal event of 3 July 2019 destroyed the STR02 instrumentation, interrupting the acquisition of CO2 monitoring data from soils after 20 years of hard and productive work [20,24,27], which well supported the geochemical surveillance for the evaluation of the volcanic activity level of Stromboli

Summary

Introduction

Volatiles degassing from volcanic systems is a peculiar and useful tool to monitoring the volcanic activity to the aims of characterizing the geochemistry of shallow plumbing systems and forecasting and individuating the changes of the volcanic activity level. For this reason, many scientists have carried out investigations on shallow volatile degassing to characterize the normal activity level and for identifying the main active degassing structures that are present on the studied volcanic systems [1,2,3,4,5,6,7,8,9,10,11,12].

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Conclusion