Thermal surveys of the Vulcano Fossa fumarole field 1994–1999: evidence for fumarole migration and sealing

The ring-shaped thermal field of Stefanos crater, Nisyros Island: a conceptual model

“…While the present study introduced additional complexities to be considered when inferring deeper geological settings from thermographic data, repeated surveys can witness the evolution of the fumarole field. The thermal field of some volcanoes, e.g., Vulcano Island, Iwodake, and Colima (Harris and Maciejewski, 2000;Matsushima et al, 2003;Stevenson and Varley, 2008) have experienced temporal and spatial changes. Such changes are common in active volcanic and geothermal settings and our results suggest that the observation and monitoring of lithologies, fault and fractures, and stresses can improve the understanding of those changes.…”

“…These may be, for instance, the stress field, the presence of faults and fractures, or the lithology (Mongillo and Wood, 1995;Dobson et al, 2003;Finizola et al, 2003;Revil et al, 2008;Schöpa et al, 2011;Peltier et al, 2012). Thermal anomalies can be detected at the surface by direct measurements and by satellite-based or hand-held infrared camera measurements (Bukumirovic et al, 1997;Harris and Maciejewski, 2000;Chiodini et al, 2007;Harris et al, 2009). These measurements alone cannot however explain which factors control the permeability complexities and the thermal expression.…”

“…Faults and fractures, in particular, control the permeability of the rock masses according to Darcy's cubic law (Caine et al, 1996;Faulkner et al, 2010), whereas the permeability of soils relates to the grain-size distribution as well as compaction, cementation and alteration (Shepherd, 1989;Benson et al, 1995); consequently they all accomplish convective heat flow (Hardee, 1982). Variations in volcanic and geothermal activity have been frequently observed at sites such as Vulcano Island, Italy (Bukumirovic et al, 1997;Harris and Maciejewski, 2000), at Iwodake Volcano, Japan (Matsushima et al, 2003), at the Solfatara of Pozzuoli, Italy (Chiodini et al, 2007), and at Colima, Mexico (Stevenson and Varley;, but they were alternatively attributed to changes in the magmatic or hydrothermal source (Stevenson, 1993), to permeability changes due to conduit sealing by deposition or tectonic activity (Harris and Maciejewski, 2000), or a combination thereof. Examples of chemical and thermal changes were also recently documented for the 2011-2012 unrest episode at Santorini (Parks et al, 2013;Tassi et al, 2013).…”

Remote Sensing and Geodetic Measurements for Volcanic Slope Monitoring: Surface Variations Measured at Northern Flank of La Fossa Cone (Vulcano Island, Italy)

“…Increased fumarolic activity and temperature and ground fracturing resulted in enhanced slope instability, causing part of the northeastern sector (a volume of ~2 × 10 5 m 3 ) to slide into the sea on 20 April 1988 [30]. Although vent temperatures have generally been declining since the mid-1990s, the fumarolic system is still active and undergoes changes in vent temperature, location and gas output [31][32][33][34]. The ground deformation at Vulcano is currently monitored by GPS, electro-optical distance measurements (EDM) and leveling campaigns and by continuous tilt and GPS.…”

Thermal and geochemical signature of Poás Volcano, Costa Rica (MARCH 2009)

“…To make a first-order compensation of the detected radiance for atmospheric attenuation, the measured air temperature (Tamb), relative humidity (RH) and path length, were entered together with an estimate of surface emissivity of the target into the camera software for internal modelling. Following Harris and Maciejewski (2000), we used emissivity of 0.97 to track temperature variations at the dome fumaroles, and, in agreement with Salisbury & D'Aria (1992) and Hernández et al (2007), emissivity of 0.96 for imaging of the lake surface. Tamb and RH were measured using a portable atmospheric parameter sensor at the start and end of the acquisition.…”