Combining Ground‐ and ASTER‐Based Thermal Measurements to Constrain Fumarole Field Heat Budgets: The Case of Vulcano Fossa 2000–2019

Abstract

Vulcano Fossa's fumarole field (Italy) has been active for more than a century and has become a well‐studied benchmark for fumarolic degassing, often being considered the “model” hydrothermal system. Satellite thermal monitoring is increasingly being used to monitor such systems, so we here use Vulcano to test a new method for assessing heat flux at such systems. Our methodology involves converting ground‐based vent temperature measurements to heat fluxes emitted by the fumaroles, with the diffuse heat flux obtained from satellite‐sensor (in our case Advanced Spaceborne Thermal Emission and Reflection Radiometer) data. While diffuse heat losses were typically 9 MW, vent heat losses were 1 MW. The average total flux of 10 MW over the 19‐year period of study places Vulcano in the top 20 most active hydrothermal systems globally. This work highlights the value of high spatial resolution infrared satellite data in building thermal inventories for persistently active hydrothermal systems.

A Hand-Held Sensor System for Exploration and Thermal Mapping of Volcanic Fumarole Fields

“…We may emphasize that this method can augment remote sensing methods, such as in [ 25 ]. Alternatively, airborne systems could be used to gain a broad large-scale model beforehand, which is then used to select interesting spots that are investigated in detail with the hand-held system.…”

“…The infrared data is automatically processed using the software Optris PI Connect [ 26 ] and the processed pixel-wise temperature values are logged. We selected an operating range of 0 to 250 C, which covers most of the fumaroles with an estimated mean vent temperature of 185 C in 2019 [ 25 ]. A Field Programmable Gate Array (FPGA) synchronously triggers both visual cameras and handles the timestamp assignment for all sensor data.…”

“…Mannini et al . [ 25 ] used satellite- and stationary ground-based surveys in conjunction with measurements of a hand-held thermal camera that is used to directly sample vent temperatures. In this context, hand-held thermal cameras allow the investigation of structures in greater detail with georeferenced data using built-in GPS solutions.…”

A multi-decadal view of the heat and mass budget of a volcano in unrest: La Soufrière de Guadeloupe (French West Indies)

“…Gaudin et al, 2015). Our heat balance is thus (Sekioka and Yuhara, 1974;Matsushima et al, 2003;Harris, 2013;Mannini et al, 2019)…”

“…In many cases, this far exceeds the fumarolic output in terms of energy transfer (e.g. Matsushima et al, 2003;Mannini et al, 2019). Due to the high heat capacity of water, direct fumarolic degassing and diffuse small fumarole/soil degassing are generally the two major components of heat loss at hydrothermal volcanic systems (Aubert, 1999;Chiodini et al, 2001).…”