Volcano

 A volcano is an opening, or rupture, in a planet's surface or crust, which allows hot, molten rock, ash and gases to escape from below the surface. Volcanic activity involving the extrusion of rock tends to form mountains or features like mountains over a period of time.

A volcano is a hole where melted rock called magma or rock and ashes are thrown up from inside the earth. Volcanoes are commonly known around the world for bringing huge destruction as they erupt. When most people think of volcanoes they think of hot boiling lava. Many people do not realize that instead of only erupting lava, it also erupts ash and gas. A volcano works in the following sequence.

Volcanic eruption 

A volcanic eruption is the point in which a volcano is active and releases its power, and the eruptions come in many forms. They range from daily small eruptions which occur in places like Kilauea in Hawaii, or extremely infrequent super volcano eruptions (where the volcano expels at least 1,000 cubic kilometers of material) in places like Lake Taupo, 26,500 years ago, or Yellowstone Caldera, which has the potenetial to become a super volcano in the near geological future. Some eruptions form pyroclastic flows, which are high-temperature clouds of ash and steam that can trial down mountainsides at speed exceeding an airliner. According to the Toba catastrophe theory, 70 to 75 thousand years ago, a super volcanic event at Lake Toba reduced the human population to 10,000 or even 1,000 breeding pairs, creating a bottleneck in human evolution