Ap us Essay

Submitted By emilycorp
Words: 591
Pages: 3

Do all volcanoes form at subduction zones? There are many different types of volcanoes and many different ways they’re formed. Some of the plates diverge away from each other forming volcanoes in the middle of them, or also through convection. Subduction volcanoes are formed from one tectonic plate moves under another tectonic plate down into Earth’s mantle. The Ring of Fire is an example of many volcanoes formed by subduction. It is the most volcanically active belt on Earth, surrounding the Pacific Ocean. These volcanoes occur from two converging on one another, one of those being oceanic. The oceanic plate bends beneath the continental plate going into Earth’s mantle creating a trench. The deepest trench is 11 kilometers below sea level, known as the Mariana Trench. The picture on the right shows the Aleutian Trench where subduction volcanism was formed. As the trench is formed down in the mantle, the oceanic plate heats up and rises with sediment forming magma, the magma rises up through the over- lying plate to erupt at the surface. As that plate being a continent it formed a chain of volcanoes as the Ring of Fire. The Ring of Fire contains 452 volcanoes, over 75% is active. It stretches through North America, South America, Japan, into New Zealand and across Bering Strait. Mount Ruapehu in New Zealand is one of the most active which erupts about every 50 years.
Another type of formation of volcanoes is spreading center volcanism, which occurs at mid- ocean ridges. That is where two plates diverge away from each other, opening space between them. As the plates pull apart hot magma rises from the mantle forming magma chambers, where the magma will erupt to the surface from there. Also the high heat from mid-ocean ridges will form hydrothermal vents, which form from water seeing down and is heated from the rocks lying on the magma chamber. This hot water on surface contains lots of silica and numerous metals from lava. An example is the Iceland plume which was said to have seen the earliest volcanic rock about 56-60 million years ago.
Volcanoes can also be formed from Interplate (hotspot) Volcanism or Convection. These are active sites of volcanism within plate interiors, these hotspots are from hot mantle in a mantle plume which is generated in the lower mantle and