A volcano eruption occurs when there is a sudden release of magma, gas, and ash from a volcano. This happens when pressure builds up inside the Earth, causing the magma to rise through cracks in the Earth's crust. When the pressure becomes too great, it can lead to an explosive eruption, sending ash and debris high into the atmosphere. Eruptions can vary in intensity and can create various landforms, such as lava flows, ash deposits, and volcanic craters. Some famous eruptions include the eruption of Mount St. Helens in 1980 and the Krakatoa eruption in 1883, both of which had significant impacts on the environment and nearby communities.