At convergent boundaries, tectonic bowl collide v each other. The events that take place at these borders are linked to the varieties of bowl — oceanic or continental — that room interacting.
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Subduction Zones and Volcanoes
At some convergent boundaries, an oceanic plate collides through a continent plate. Oceanic crust often tends to be denser and thinner than continental crust, for this reason the denser oceanic crust gets bent and also pulled under, or subducted, in ~ the lighter and also thicker continent crust. This develops what is dubbed a subduction zone. Together the oceanic crust sinks, a deep oceanic trench, or valley, is formed at the sheet of the continent. The crust continues to be required deeper into the earth, whereby high heat and also pressure reason trapped water and other gasses come be exit from it. This, in turn, makes the basic of the crust melt, creating magma
The magma created at a subduction zone rises up towards the earth\"s surface and builds increase in magma chambers, wherein it feeds and also creates volcanoes top top the overriding plate. As soon as this magma find its method to the surface through a vent in the crust, the volcano erupts, expelling lava and ash. An example of this is the band of active volcanoes that encircle the Pacific Ocean, regularly referred to together the Ring that Fire.
Illustration showing how island arcs space formed.
A subduction region is also generated as soon as two oceanic plates collide — the enlarge plate is forced under the younger one — and it leader to the development of chains of volcanic islands known as island arcs. Examples include the Mariana archipelago in the western Pacific Ocean and the Aleutian Islands, off the coastline of Alaska.
Since the collision and subduction of bowl is no a smooth process, large, powerful earthquakes are one more phenomenon that an outcome from this form of interaction. Earthquakes produced in a subduction zone can also give increase to tsunamis. A tsunami is a large ocean wave caused by a sudden change on the ocean floor, such together an undersea earthquake. If the tide reaches land, the can reason incredible destruction, choose the oriental Tsunami, which killed much more than 200,000 human being in 11 countries across the Indian Ocean region in December 2004.
Collision Zones and Mountains
What happens once two continental plates collide? since the rock consisting of continental plates is typically lighter and also less dense than oceanic rock, it is also light to get pulled under the earth and turned into magma. Instead, a collision in between two continental plates crunches and folds the rock at the boundary, lifting that up and also leading to the development of mountains and also mountain ranges.
An instance of this mountain-building process is the Himalayan selection in southern Asia. Comprise the highest possible mountain peaks in the world and traversing the modern-day nations of India, Pakistan, China (Tibet), Bhutan, and also Nepal, the Himalayas were created by the collision that the Indian and Eurasian Plates. This procedure began after ~ the breakup of Pangaea, as soon as India came to be an island continent and began traveling northward toward Asia. The island the India slammed into Asia about 40 to 50 million years ago near modern-day Tibet, crushing and also folding the key to type the Himalayan hill range. Its ideal known peaks, mount Everest and K2, are among several the measure end 8,000 meters (26,000 feet) high at your summits. Because the Indian plate is proceeding in its northward movement into Asia, the Himalayas proceed to grow higher each year by small amounts (5 to 20 mm or 1 inch per year).
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Image credits: Animations and also illustration that oceanic-oceanic plate collision adjusted from drawings by jane Russell native Jacquelyne Kious and Robert Tilling, This Dynamic Earth, USGS, pp. 37 and 40.