Volcano is a rupture in the crust of a planetary mass object such as earth 
That sounds technical. I know that magma spews out.
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, rigid tectonic plates that float on a hotter, softer layer in its mantle. Therefore, on Earth, volcanoes are generally found where tectonic plates are diverging or converging, and most are found underwater. For example, a mid-oceanic
ship missile
Other uses.
- "Vulkán", the Hungarian name for the city of Vulcan, Hunedoara, Romania
- Vulkan (API), an open standard API for explicitly accessing GPU graphics and compute acceleration
- Vulkan is the Primarch of the Salamanders Space Marines (Warhammer 40,000) in the Warhammer 40,000 universe
See also.
- Vulcan (disambiguation)
- Volcan (disambiguation)
- Volcano, a rupture on the crust of a planetary-mass object