Volcano were proposed for volcano behavior before the modern understanding of the Earth's mantle structure as a semisolid material was developed. For decades after awareness that compression and radioactive materials may be heat sources, their contributions were specifically discounted. Volcanic action was often attributed to chemical reactions and a thin layer of molten rock near the surface. Volcano A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. Earth's volcanoes occur because its crust is broken into 17 major,
Solfatara (volcano) Solfatara (volcano) Solfatara () is a shallow volcanic crater at Pozzuoli, near Naples, part of the Phlegraean Fields () volcanic area. It is a dormant volcano, which still emits jets of steam with sulfurous fumes. The name comes from the Latin, "Sulpha terra", "land of sulfur", or "sulfur earth". It was formed around 4000 years ago and last erupted in 1198 with what was probably a "phreatic" eruption - an explosive steam-driven eruption caused when groundwater interacts with magma. The crater floor is a popular tourist attraction, as it has many fumaroles and mud pools. The area is well known