Emissions from volcanoes

Abstract

Around 380 volcanoes were active during the last century, with around 50 volcanoes active per year (Andres and Kasgnoc, 1998). Volcanic activity is not randomly distributed over the Earth, but is linked to the active zones of plate tectonics, as shown in figure 1. More than 2/3 of the world's volcanoes are located in the northern hemisphere, and in tropical regions. The emission of volcanic gases depends on the thermodynamic conditions (pressure, temperature) and on the magma type (i.e., its chemical composition, which in turn depends on the tectonic environment).