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,
Zuidwal volcano Zuidwal volcano The Zuidwal volcano is an extinct volcano in the Netherlands at more than below ground under the Wadden Sea, between Harlingen and Vlieland, just south west of the island Griend. The volcano was last active during the late Jurassic, (about 160 - 148 Ma ago) and has since been covered by about of sedimentary rock, most of it shale and sandstone from the Cretaceous. The volcano was discovered in 1970 when the French oil company Elf Aquitaine was doing test drills in the Wadden Sea, hoping to find a gas field that a seismic survey had indicated. To