When a volcano erupts, magma from beneath the Earth is forced out of the volcano's mouth in the form of molten lava. Large amounts of gases and ash can also be released with the lava, depending on the type of eruption.
Volcanoes erupt due to pressure that the weight of the rocks puts on the magma and forces it to the surface out any available vent or exit provided to it. The magma is in a reservoir like area under the surface and the pressure from the rocks causes the less dense magma...
A volcano erupts through the build-up and release of pressure, whether that pressure is of its underlying magma, water or both. This release can be explosive, as it was in the famous eruption of Mt. Vesuvius that destroyed Pompeii, or it can be slow and effusive, as it ...
A volcano erupts when the pressure of a subterranean pool of magma becomes great enough to crack the earth's crust. Whether the eruption results in a violent explosion or a slow seepage depends on several different factors, according to How Stuff Works.
Volcanoes erupt to release pressure built up in the magma chamber by expelling the magma as lava. Along with lava, a volcanic eruption releases ash and greenhouse gases such as sulfur dioxide and carbon dioxide.
The first volcano erupted approximately 4.5 billion years ago. This is when the earth first came into existence, and long before the first humans walked the earth, according to Scholastic, Inc.
According to the UCSB Geology Department, a volcanic eruption is defined as a volcanic event resulting in the emission of gases, lava, ash or other material from a volcano. These can manifest as a single eruptive pulse, an eruptive phase or an eruptive episode.