Editorial for Special Issue “Present and Past Submarine Volcanic Activity (1)”

Over 1 million volcanoes on the Earth surface occur in marine and submarine environments
in different geodynamic contexts. Most of this volcanic activity remains almost
unexplored due to the extreme conditions of deep underwater observations of the eruptive
processes. Despite this, the link between volcanism, tectonics, and seabed morphology
represents a key aspect for developing new interpretative geological models and verifying
or refining older interpretations. Tectonics often drives volcanism, and they both shape
the seafloor morphology. Therefore, new observational capacities and multidisciplinary
data integration increase our possibility to reach and interpret deep-seated geological structures.
As an example, the advances in exploration geophysics allowed to illuminate the
submerged portion of volcanic islands and deep volcanic seamounts. A number of 2–3D
geological models about seafloor volcanic structures, their feeding systems, hydrothermal
system extension and depth are now available using seismic, multibeam swath bathymetry
and potential field methods, as well as their detailed digital elevation models. Therefore,
the multidisciplinary approach becomes an essential tool to investigate deep marine environments
which would otherwise be unreachable, and to unravel what is going on below
sea level in remote and almost completely unreachable environments. On the other hand,
coastal volcanism and volcanic islands are better known than deep edifices; however, their
study is essential to better understand their growth, their dismantling mechanism and their
activity, which directly influences the safety and security of manufacts, engineering operas
and human lives. The target of the Special Issue volume was decided by the five published papers
which crosscut different and complementary aspects of submarine volcanism, useful for the
understanding of past and present activity of the proposed case studies.

1. Cocchi, L.; Caratori Tontini, F.; Muccini, F.; de Ronde, C.E.J. Magnetic Expression of Hydrothermal Systems Hosted by Submarine
Calderas in Subduction Settings: Examples from the Palinuro and Brothers Volcanoes. Geosciences 2021, 11, 504. [CrossRef]
2. Olivé Abelló, A.; Vinha, B.; Machín, F.; Zerbetto, F.; Bakalis, E.; Fraile-Nuez, E. Analysis of Volcanic Thermohaline Fluctuations of
Tagoro Submarine Volcano (El Hierro Island, Canary Islands, Spain). Geosciences 2021, 11, 374. [CrossRef]
3. Dura, A.; Mertzimekis, T.J.; Nomikou, P.; Gondikas, A.; Gómez Míguez, M.M.; Bakalis, E.; Zerbetto, F. The Hydrothermal Vent
Field at the Eastern Edge of the Hellenic Volcanic Arc: The Avyssos Caldera (Nisyros). Geosciences 2021, 11, 290. [CrossRef]
Geosciences 2022, 12, 458 3 of 3
4. Ninomiya, T.; Shimoyama, S.; Taniguchi, S.; Takahashi, T.; Danhara, T.; Iwano, H. Age of Initial Submarine Volcanism in the
Paleo-Tsushima Basin and Implications for Submarine Volcanism in the Opening Stage of the Japan Sea in Northern Kyushu.
Geosciences 2021, 11, 363. [CrossRef]
5. Verolino, A.; White, J.D.L.; Baxter, R.J.M.; Schipper, C.I.; Thordarson, T. Characteristics of Sub-Aerially Emplaced Pyroclasts