Structure And Dynamics Of Hydrothermal Systems In Polar Volcanic Calderas

HYDROCAL project aims at characterizing the structure and dynamics of hydrothermal systems in polar and sub-polar active volcanic calderas, evaluating any particularities due to their location at higher-latitudes and under extreme climate conditions. As case studies, we propose Deception Island (Antarctica) and Torfajökull (Iceland) calderas in order to stablish similarities and differences among both examples to provide, at the end, a full conceptual and evolutionary model of caldera-hosted hydrothermal systems in polar and sub-polar areas. Obtained results will be compared to the most documented and well-known active caldera hosting an hydrothermal system and located in a temperate climate: Campi Flegrei (Italy).

Active volcanic areas are commonly related to the presence of hydrothermal systems. Particularly prone to host these are volcanic collapse calderas, depressions resulting from the sinking of the chamber roof into the magmatic reservoir due to the rapid withdrawal of magma during the course of an eruption. Following the caldera collapse, water infiltrates through the ring fractures and caldera-crossing faults, which form zones of fracture permeability. Once at depth, this water is heated up by the remnant, or newly intruded, magma and raises again to the surface generating fumaroles and hot springs, altering rocks, etc. During the last years, it has been evidenced that characterizing the structure and dynamics of hydrothermal systems of active volcanic calderas is fundamental for:

1. advancing in our understanding of volcanic processes occurring after the caldera collapse;
2. improving volcanic hazard assessment by assessing the future occurrence of phreatic and phreatomagmatic eruptions and their related hazards and hence;
3. understanding the processes behind caldera unrest and improving our capacity to correctly interpret monitoring signals,
4. more effective knowledge-based exploitation of mineral and energetic resources.

Many research studies have been done to understand the dynamics of hydrothermal systems in worldwide volcanic calderas (e.g., Campi Flegrei, Italy). However, the current knowledge on hydrothermal systems in polar and sub-polar calderas is scarce and mostly concentrated on individual Icelandic calderas.