Analysis of Thermal Anomalies in Volcanic Areas Using Multiscale and Multitemporal Monitoring: Vulcano Island Test Case

Malvina Silvestri,Antonino Pisciotta,Federico Rabuffi,Iole Diliberto,Claudia Spinetti,Maria Buongiorno,Valerio Lombardo,Laura Colini,Massimo Musacchio

doi:10.3390/rs11020134

Abstract

Surface temperatures derived by 208 ASTER and L8 satellite imagery were analysed to test multiscale and multitemporal capability through available sets of thermal data to support the volcanic monitoring of Vulcano Island in Italy. The analysis of thermal historical series derived by ASTER and L8 shows that two are the main thermally active areas: La Fossa crater and the mud pool of Fangaia. In this work we aimed to assess the correlation between the satellite-retrieved temperatures with those measured during the daytime ground field campaign conducted within the same time period and, in particular cases, simultaneously. Moreover, nighttime data acquired by an airborne and field campaign were processed with the same methodology applied to satellite data for a multiscale approach verification. Historical meteorological data acquired from a weather station were also considered. Statistically significant correlations were observed between nighttime acquisitions and meteorological data. Correlations were also significant for temperature measured during the airborne campaign, while differences up to 50% with daytime acquisition during the ground field campaigns were observed. The analysis of the results suggests that within nighttime data acquisition, differences between satellite-derived temperatures and ground temperature measurements are considerably reduced; therefore nighttime data acquisition is recommended to detect thermal anomalies.

Highlights

The aim of volcanic surveillance is the interpretation of the observed data in order to highlight changes of volcano activity and to define the potential risks for human health and activities
The multitemporal characteristics have been approached by comparing long-term time series and discontinuous measurements
The potential of these new applications could improve the results of direct monitoring systematically performed for volcanic surveillance since 1990 by a network of stations for ground temperature measurements

Summary

Introduction

The aim of volcanic surveillance is the interpretation of the observed data in order to highlight changes of volcano activity and to define the potential risks for human health and activities. During inter-eruptive periods, the thermal emissions by hydrothermal fluids, the emission of steam through the fumaroles and even the diffuse heat release from the ground are a significant part of the total energy released by the volcano This slow and restless energy release is, in the long term, comparable to the seismic release of volcano-tectonic origin [6,7,8,9,10,11]. The volcanic system is very dynamic and it is affected by volcano tectonic processes which could change the areal distribution and intensity of thermal anomalies This process requires an accurate thermal mapping of the ground, which needs to be extended beyond the area where there is major evidence of fumarole release. The InfraRed (IR) optical sensors promise good results for extended thermal mapping, once detection limits are ascertained and correlated with ground measurements

Objectives

Results

Conclusion