In a volcanic eruption, lava, volcanic bombs and ash, and various gases are expelled from a volcanic vent and fissure. While many eruptions only pose dangers to the immediately surrounding area, Earth's largest eruptions can have a major regional or even global impact, with some affecting the climate and contributing to mass extinctions.[1][2] Volcanic eruptions can generally be characterized as either explosive eruptions, sudden ejections of rock and ash, or effusive eruptions, relatively gentle outpourings of lava.[3] A separate list is given below for each type.