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,
Under the Volcano 1984 it served as the basis of a film of the same name. In 1998 the Modern Library ranked "Under the Volcano" at number 11 on its list of the 100 best English-language novels of the 20th century. Lowry had already published one novel, "Ultramarine" (1933), by the time he was working on "Under the Volcano", and in 1936 wrote a short story called "Under the Volcano" containing the kernel of the future novel. That story was not published until the 1960s; passages of it are found also in the account of Sigbjorn Wilderness, found in "Dark as the Grave