What makes the difference when a volcano erupts violently and quietly?
What makes a volcano erupt violently or quietly actualy depends on the type of magma inside of it. The magma in volcanoes have different compositons from each other. magmas are sometimes classified by their silica content, which determines how viscus they are (how fluid they are). The more silica the lava has in it, the more thick it is. In very fluid or basaltic lavas, the silica content is around 50%. On the other end of the scale are granitic magmas that have a very high silica content (90%). when a volcano containing fluid magma erupts, the gas within the lava is easily relased, resulting in lava fountains like hawai’i’s Kilewea. In a volcano that contains thick, granitic magma, the gases within the lava are trapt inside of it until the eruption lets the gases out, resulting in a violent, distructive explosion such as Mt St Helens.
