The ring of fire is a region in the Pacific Ocean of major volcanic and seismic activity. Approximately 90 percent of all the earthquakes occurring in the world have their origin in the Pacific ring of fire. The ring of fire lies in an area that is characterized by a continuous series of oceanic trenches, volcanic arcs and tectonic plate movements. This area of volcanic and tectonic activity covers approximately 40,000 km (25,000 miles) along the edges of the Pacific Ocean and the continents. The ring of fire is home to an approximate number of up to 450 volcanoes, of which a little over 75 percent are active volcanoes. 90 percent of the world´s active volcanoes are located along the ring of fire, and 90 percent of the world´s earthquakes have their origin in the ring of fire.
Area of the ring of fire
The ring of fire covers an area that extends from New Zealand in the southwestern Pacific and continues northward along the most eastern coastal borders of the Asian countries; then it continues in the northern Pacific across the Aleutian Islands of Alaska. From this point, it continues toward the south along the western coast of North America and down to Mexico, Central America and all the way to Peru and Chile in South America. The movement and collisions of major lithospheric plates in the region of the ring of fire produces frequent earthquakes and volcanic eruptions at their boundaries.
The ring of fire results from the effects of the collisions among lithospheric plates on the Earth´s crust. Some well known volcanoes in the world were formed in the ring of fire. In the U.S., the Gorda plate, located off the coast of California, and the Juan de fuca plate have formed Mt. St. Helens. Also in North America, the Cocos plate is being subducted underneath the North American plate, affecting volcanoes such as the Popocatepetl and Paricutin, in Mexico. The collisions between the Nazca plate and the South American plate in South America have created the Andes cordillera.
Tectonic plate theory
Tectonics and the theory of tectonic plates which originated from the theory of continental drift were not developed until about the first decades of the 20th century; however, the concept of continental drift was not accepted by the scientific community until after the development of the concepts of sea floor spreading in the late 1950s and early 1960s. The Earth´s crust consists of eight major tectonic plates and a small number of minor tectonic plates. The formation of trenches, mountains, volcanoes and mid-ocean ridges occurs at the borderlines of these plates, where friction and lateral movements are very common.
The Pacific plate
In the Pacific Ocean, the sea floor is fragmented into a number of tectonic plates. These plates continuously collide, slide and sink underneath other plates. The process by which a plate sinks underneath another plate is known as subduction, and the area where seismic and volcanic activity occurs along the boundaries of the plates is called the subduction zone. The enormous amount of energy released by the colliding tectonic plates melts rock into magma and produces earthquakes and volcanic eruptions. The largest tectonic plate in the ring of fire is the Pacific plate, which subducts underneath the North American plate.
Plate tectonics opened a new perspective to an understanding of the evolution of the planet. In 1912, Alfred Wegner, who was a meteorologist, described continental drift in a book called ¨The Origin of Continents and Oceans.¨ The theory of continental drift gave origin to the theory of plate tectonics years later. By using seismographs, scientists are able to locate the region where earthquakes tend to concentrate. The movement of tectonic plates is studied by satellite data instruments and ground measurement stations. According to nationalgeographic.com, the ring of fire is the result of plate tectonics. The boundaries where tectonic plates meet can be convergent, divergent or transformational boundaries.