The role of water in volcanism

Water plays an extremely important role in volcanism: it acts as an evacuator of viscous melts in a variety of ways, which is ensured by the presence of relevant properties of its phase states, which successively changing with the fall of the environmental parameters. In this sense, the supercritical (fluid) state of water is especially significant. The paper provides a summary of fluid properties that are unique in many ways. The properties determine the relationship between water fluid and silicate melt, which in turn explains the cause of volcanic phenomena and the course of eruptions: explosions of different power, the emergence of the so-called fluidized mass, scorching clouds, landslides and breakthroughs on the slopes, the formation of ignimbrites, as well as the mechanism of gas transport to the foot of volcanoes. Both by role and quantity, water is the main volcanic substance, which together with the silicate melt constitutes magma.