Temperatures recorded from January 2019 to February 2023 in the high-temperature fumaroles of the active cone of La Fossa Caldera

Abstract

The thermal monitoring of high-temperature fumaroles (HTF) located at the summit of La Fossa cone (Island of Vulcano, Italy), is based on the acquisition of high temporal resolution data. The HTF stations are part of a multi-parameter surveillance network. The longest time series of HTF temperatures has tracked the thermal effects of many exhaling crises that have affected the active volcanic system under la Fossa caldera, for over 40 years. The HTF records always showed a medium term period (from weeks to several months) of increasing heat flow before of the following impulsive onset. The last impulsive onset occurred in 2021, and reached the acme of the exhaling crisis in early November. The INGV surveillance network, detected different anomalous signals, allowing the scientific community to closely follow the surface effects of processes originated at depth. The very first signals detected during unrests were the increases in outlet temperatures and steam output from fumaroles, correlated to an enhanced concentration of acidic gas species. The episodes of unrest have been generally accompanied by an increase in seismo-volcanic events with, sometimes negligible, ground deformation. On this close conduit volcano, we are facing the upgrading of thermal monitoring at the ground level. Starting from these long-term monitoring datasets, used as ground control data, we are also testing the most advanced technical facilities supplied by the optical sensors (either ground, air or space based) to define the time variations of the thermal release over large surfaces.