Various factors trigger a volcanic eruption. The three predominant factors are the magma's buoyancy, the pressure from the gases that separate in the magma and the merger of a new batch of magma with a chamber already filled with magma.Continue Reading
The melting of rock inside the earth produces a melt with more volume than the rock but the same mass. This melt is less dense than the rock that surrounds it. The lighter magma moves upward because of its buoyancy, and if the density between the surface and zone of its generation is less than the overlying and surrounding rocks, it erupts.
A few magma compositions contain dissolved volatiles such as water and carbon dioxide. The amount of gases dissolved in the magma is zero at atmospheric pressure, but it increases with an increase in pressure. In andesitic magma, which is saturated with water, the solubility of water decreases as the magma moves upward, and the water separates from it in the form of bubbles. When the volume of bubbles in the magma reaches about 75 percent, disintegration of magma into partially solid and molten fragments happens, along with an explosive eruption. Injection of more magma inside an already filled magma chamber forces some of the magma to move toward the surface, causing an eruption..Learn more about Volcanoes
Common safety precautions for volcanic eruptions include staying away from the eruption, preparing to evacuate as instructed by local officials, knowing an appropriate evacuation route and maintaining sufficient gas in the car. Additionally, people who live near an active and potentially explosive volcano should maintain an emergency kit containing a breathing mask, goggles, a flashlight and a battery-operated radio in the event of power failure.Full Answer >
Examples of volcanic eruptions during the 21st century include the eruption of Iceland's Hekla volcano in 2000, North Sumatra's Mount Sinabung in 2014 and Japan's Mount Ontake in 2014. Other eruptions include the Tungurahua volcano in Banos, Ecuador, in 2014 and Mount Merapi in Indonesia in 2010.Full Answer >
The most common and serious types of volcanic hazards are flowing lava, falling ash, glowing avalanches and moving mud and debris. The exact hazard level varies depending on the type of volcano erupting. Additional hazards include the emission of hazardous gases and eruption clouds, which are dangerous to planes and helicopters.Full Answer >
A volcanic hotspot is an area in the earth’s mantle in which thermal plumes provide the necessary heat and magma for volcanic activity over a long period, explains the U.S. Geological Service. These hotspots are the basis for the creation of land, including the Hawaiian Islands.Full Answer >