The volcanic system of Ischia is characterized by an intense hydrothermal activity, documented
since the early 16th century by the study of Iasolino [1588], which represents the first systematic
analysis of the thermal springs of the island for therapeutic purposes. Later studies partially
contributed to the enhancement of knowledge on the volcanic, hydrogeological and
hydrothermal features of the island, highlighting the strong interaction between hydrothermal
flowpaths and volcanotectonic
processes. The reconstruction of the hydrothermal system
becomes, therefore, a fundamental element for territorial planning, not only in terms of
management of the huge water and geothermal resource, but also and above all in a perspective
of prevention and mitigation of volcanic risk. Thermal springs, fumaroles and clay deposits due
to the hydrothermal alteration of volcanic products testifies for the existence of an active deep
hydrothermal system. However at Ischia the geochemical characterization of fluids and
groundwater, performed through sampling and analysis of a discrete number of scattered
springs, wells and fumaroles, has been used for the definition of the origin and structure of
hydrothermal systems as a whole, as the hydrogeological information is incomplete. Moreover,
volcanic hydrothermal systems, such as that characterizes the island of Ischia, are particularly
difficult to analyze and outline, as the groundwater resources are the result of an articulated
and dynamic interaction among meteoric water, sea water and fluids of deep origin. In such
cases, the need for an interdisciplinary approach is evident, involving knowledge and research
methods ranging from geology to volcanology, geophysics, geochemistry, mineralogy and
hydrogeology. With particular reference to the functional and structural representation of the
geothermal system of the island of Ischia and the resulting correlations with the volcanotectonic
processes, the examination of previous information highlights the need to update and improve
the knowledge on groundwater hydrodynamics and mineralization processes.
Therefore, the present work represents a strong interdisciplinary action that, starting from the
design and implementation of a database on the existing geological/volcanological and
hydrogeological information, contributes to highlight the critical issues, define an operating
scheme of the hydrogeothermal
system of the island of Ischia, and upgrade its hydrogeological,
geochemical and volcanic monitoring system, in order to contribute to the mitigation of volcanic
and related risks. The knowledge of groundwater dynamics and pathways, in fact, is of
fundamental importance for understanding the water/magma interaction processes in case of
realimentation
of the shallow magmatic system, and the assessment of the possibility of
phreatic explosions occurrence. Moreover, the knowledge of the thermal fluids’ circulation and
the related rock alteration processes is of paramount importance in the definition of the
mechanic characteristics of rock masses and their proneness to failure