volcanism is the activity through which the magnetic material is expelled from the Earth's interior to the surface. The volcano is the mountain formed from the eruptions of larvae (magmatic material in a molten state), rock fragments, ash, gases and vapors, which come out of the crater formed on the surface.
The material expelled by volcanism is accumulated on the surface and forms the so-called volcanic relief, or false relief, which is generally cone-shaped and has a very variable height.
It is not very common for volcanism to occur in the interior of continents. Most are located at the edges of tectonic plates, particularly along the ocean coasts. Where the plates collide, the most violent eruptions occur. Where the plates separate, eruptions are more explosive. Volcanoes that constantly erupt are called active and those that are inactive are called extinct.
Volcanism in the World
The two areas where most volcanoes are concentrated are: The Pacific Circle of Fire, where 80% of the volcanoes are concentrated and forms an alignment that runs from the Andes to the Philippines, across the western coasts of North America and across the Japan. And the Atlantic Circle of Fire, Covers Central America, Antilles, Cape Verde, Mediterranean and Caucasus.
Volcanism in Brazil
There are no active volcanoes in Brazil. However, in past geological times, our country was the scene of several volcanic activities. The eruptions that occurred in the Cenozoic (Tertiary) Era led to the formation of the oceanic islands of Trindade, Fernando de Noronha, São Pedro and São Paulo.
During the Mesozoic Era, volcanic activity was very intense in Brazil, highlighting the occurrences in Poços de Caldas and Araxá (MG), São Sebastião (SP), Itatiaia and Cabo Frio (RJ) and Lajes (SC).
In the South Region, volcanism caused one of the largest basaltic spills in the world, covering an area of 1 million km², that goes from the State of São Paulo to Rio Grande do Sul, where the basaltic cliffs in the region of Towers. The basaltic spills that occurred in the Southern Plateau gave rise to the fertile soil of terra xoxa.