Temperature and conductivity anomalies as a proxy for volcanic activity at the Tagoro submarine volcano

Abstract

Temperature and conductivity fluctuations due to the hydrothermal emissions released during the degasification stage of the Tagoro submarine volcano, off El Hierro Island in the Canary Archipelago, may provide robust indicators for characterising and predicting the activity of the system. 21 CTD time series along a regular high-resolution grid were gathered in the VULCANO 1 O 16 cruise with the rosette sampler directly over the main seafloor crater (Santana-Casiano et al., 2016; Fraile-Nuez et al., 2018). Temperature and conductivity data compiled are analysed as manifestations of stochastic processes in terms of the Generalized Moments Method (GMM) (Bakalis et al., 2017; Bakalis et al., 2018). GMM provides the statistical moments of the underlying processes and delivers their structure functions being their shape an indicator of the stochastic mechanism/s goveming such a stochastic process. Our findings point to an active submarine volcano, which conveys energy to the surrounding ecosystem. Y et, both temperature and conductivity fluctuations present long tails depict to strong sub-normal processes, which change very slowly in the long time limit. Temperature and conductivity fluctuations are classified as multifractal processes whose structure functions show a crossover in two distinct regimes. Multifractality suggests the multiplicative action of at least two random processes, which can be attributed to the volcano and to the aquatic environment. From the physical view point the Tagoro submarine volcano can be defined as an open system given the variations over time of temperature moments.