Geophysical, Geodetic and Geochemical Evidence for Precursory Activity: The 2011–2012 Tagoro Submarine Eruption

Observational data recorded during the reawakening of volcanic activity in El Hierro, which ended with 2011–2012 Tagoro eruption, allow us to study the precursory activity associated with this event. This volcanic activity occurred between 1971 Teneguía eruption and the 2021 eruption in Cumbre Vieja (both in La Palma island) and represents the first such event in the Canary Islands that has been fully recorded from beginning to end by a multi-parameter monitoring network. The lack of previous instrumental data makes these data unique and a case study for a broader understanding of monogenetic volcanism. In this chapter we review previous works to collect the precursors of the historical eruptions in the Canaries, discussing which were most relevant to forecast the evolution of the eruptive processes. We find solid signs of the undergoing magmatic process in El Hierro in the evolution of the seismicity, the surface deformations and gas emissions, the changes in media properties and the appearing of gravity anomalies. Results can contribute to a better interpretation of the observational data and the correct volcanic risk assessment of future events.