Earth

Volcanic heights

A volcano is an opening of the Earth’s surface from where lava and gases come out at high temperatures. The structure of the volcano is the result of the continuous accumulations of erupted material, which then cools down. The following volcanoes have to be distinguished: linear volcanoes, that release large quantities of very fluid lava, that expands on wide areas. A typical example of them are Iceland volcanoes: long fractures that open on the ground cone-shaped volcanoes, that develop close to a circular conduct, from which the erupted material comes out directly. They are characterized by very steep slopes that originate immediately after the accumulation of lava fragments, ashes, lapilli, volcanic bombs (the so-called pyroclastic materials), which are violently expelled from the volcano mouth. In some cases, during volcanic activity, lava and pyroclastic materials are alternatively erupted. As a consequence, the so-called layered volcanoes are created, such as Stromboli and Vesuvio volcanoes in Italy shield volcanoes, which have very wide structures, such as those existing in Hawaii. Their base can be hundreds of kilometres wide and their slopes are not very steep.