Campi Flegrei volcanic surveillance by thermal IR continuous monitoring

Abstract

Solfatara and Pisciarelli areas are the most impressive example of hydrothermal activity at Campi Flegrei caldera (Southern Italy). In these areas INGV-Osservatorio Vesuviano has been handling since 2004 a surveillance network for continuous, long-term volcanological monitoring of fumaroles fields by using thermal IR acquisition stations. In this paper different methodologies of analysis applied to time series of IR scenes are introduced and discussed. In spite of substantially different approaches to data analysis, the results of these methodologies agree with ground deformation data of the same area and likely are a useful tool for volcano monitoring and long-term risk definition.

Surface Temperature Multiscale Monitoring by Thermal Infrared Satellite and Ground Images at Campi Flegrei Volcanic Area (Italy)

“…More than 300,000 people live inside the volcanic area of Campi Flegrei, (Italy; Figure 1) that also includes part of the city of Naples (about 1 million people). Due to the high volcanic risk affecting this area, continuous seismic, geochemical and ground deformation monitoring networks, aimed at volcanic surveillance, operate in the Campi Flegrei [1][2][3]. In particular, the Thermal Infrared surveillance Network (TIRNet) consists of thermal infrared ground stations intended for continuous monitoring of surface temperatures of fumarole fields located inside the Solfatara crater and in the Pisciarelli area ( Figure 1b) [2,4].…”

The automated infrared thermal imaging system for the continuous long-term monitoring of the surface temperature of the Vesuvius crater

“…The methodology is aimed to remove or reduce most of the influences on IR radiation related to external factors (e.g. emissivity and surface roughness of target, viewing angle, atmospheric effects, path length, presence of volcanic gas, etc) detected by the thermal camera [Chiodini et al 2007, Sansivero et al 2012]. This methodology has been performed by taking into account, as first step, the quality (i.e.…”

“…As second step, to build up time series, only maximum temperature values of the IR scenes belonging to 2v and 1v interval has been taken in account. Then, a background correction was chosen among different methodologies of IR time series filtering of influence of environmental factors [Chiodini et al 2007, Sansivero et al 2012.…”

“…The background filtering procedure is a simple effective method in removing the seasonal pattern from the time series of IR temperature [Sansivero et al 2012]. The correction that we applied is based on the high linear correlation observed between the maximum temperatures of the scene (T S ) and the maximum temperature value of the background area of the same image (T BKG ) (Figure 8).…”

“…emissivity and surface roughness of target, viewing angle, atmospheric effects, path length, presence of volcanic gas, etc) on the radiation detected by the thermal camera [Chiodini et al 2007]. A long period IR images time series analysis allows to quantify the influence of seasonal temperature variations on the thermal heat released from fumarole areas and to perform the seasonal trend removal in order to highlight any long and short-term subtle temperature variations of the source [Chiodini et al 2007, Sansivero et al 2011, Sansivero et al 2012.…”