New ground-based lidar enables volcanic CO2 flux measurements.

Alessandro Aiuppa,Luca Fiorani,Giancarlo Tamburello,Stefano Parracino,Simone Santoro,Giovanni Chiodini,Carmine Minopoli,Marcello Nuvoli

doi:10.1038/srep13614

Abstract

There have been substantial advances in the ability to monitor the activity of hazardous volcanoes in recent decades. However, obtaining early warning of eruptions remains challenging, because the patterns and consequences of volcanic unrests are both complex and nonlinear. Measuring volcanic gases has long been a key aspect of volcano monitoring since these mobile fluids should reach the surface long before the magma. There has been considerable progress in methods for remote and in-situ gas sensing, but measuring the flux of volcanic CO2—the most reliable gas precursor to an eruption—has remained a challenge. Here we report on the first direct quantitative measurements of the volcanic CO2 flux using a newly designed differential absorption lidar (DIAL), which were performed at the restless Campi Flegrei volcano. We show that DIAL makes it possible to remotely obtain volcanic CO2 flux time series with a high temporal resolution (tens of minutes) and accuracy (<30%). The ability of this lidar to remotely sense volcanic CO2 represents a major step forward in volcano monitoring, and will contribute improved volcanic CO2 flux inventories. Our results also demonstrate the unusually strong degassing behavior of Campi Flegrei fumaroles in the current ongoing state of unrest.

Highlights

Ratio via direct sampling[21,22], infrared-red spectrometers[23,24], or gas analyzers[25,26]
Given the prospects offered by data on the volcanic CO2 flux for forecasting eruptions, the ability to remote measure this flux with a high temporal resolution would represent a major advance in modern volcanology
We report on the results of an experiment in which a novel, ad-hoc-designed prototype of a differential absorption lidar (DIAL)[28] was used to remotely measure the volcanic CO2 flux from an active volcano for the first time

Summary

Introduction

Ratio via direct sampling[21,22], infrared-red spectrometers[23,24], or gas analyzers[25,26]. Soil-gas surveys of hydrothermal volcanoes in a quiescent condition have quantified diffuse CO2 emissions[27], but much less information has been obtained on fumarolic CO2 emissions Because of these difficulties, the volcanic CO2 flux inventory remains sparse and incomplete for most of the active volcanoes on Earth[27]. Neither crisis evolved into an eruption, each of them illustrated to scientists and stakeholders the potentially severe risk-mitigation issues and the associated required actions[35] These problems have become even more urgent given that ground uplift resumed in 201236,37 accompanied by a visible intensification of degassing activity at the main surface hydrothermal manifestations of Solfatara and Pisciarelli, in the caldera center (Fig. 1). Quantifying the CO2 output from the volcanic system is vital to interpreting—and possibly predicting—the future evolution of the volcanic system

Methods

Results

Conclusion