Editorial: External forcing on volcanoes and volcanic processes: Observations, analysis and implications

Volcanoes are complex systems that evolve in space and time as a result of their internal dynamics. These internal dynamics span both long and short time scales, reflecting the different steps for the magma to form, accumulate and evolve before being eventually erupted. All of these stages may be influenced by processes external to the volcano, although most of the evidence that has been gathered on this has considered influences on the magmatic fluids stored at crustal depths, or emerging at surface.
External forcing acts either through the stress or gravitational fields that may accelerate or slow down the transfer of magma towards the surface. Changing tectonic stresses and Earth tides may induce changes in the dynamical state of volcanoes, ultimately providing the triggers that may lead to eruption. Water, which is ubiquitous on Earth, and present in its different fluid and solid envelopes, appears to play a key role, acting on volcanic systems from pore- to global-scale in various ways (hydrological modulation, ice cap loading), due to its physico-chemical properties.
This Research Topic brings together contributions, which provide new constraints and lines of evidence on the nature and variety of external processes influencing activity at quiet, restless and erupting volcanoes.