Volcanoes are common natural disasters and are generally divided into three categories: active volcanoes, dormant volcanoes and extinct volcanoes. Today's volcanoes that erupt frequently or periodically are active volcanoes. Volcanoes that have erupted in human history but have been dormant for nearly a hundred years are dormant volcanoes. Extinct volcanoes are volcanoes that have never erupted in history. In fact, there is no strict distinction between dormant volcanoes and active volcanoes. There are more than 2,000 extinct volcanoes, 516 active volcanoes, and many dormant volcanoes around the world. It is mainly concentrated on the edges of the major plates.
Pacific Rim Volcanic Belt
The Pacific volcanic belt is divided into the eastern Pacific volcanic belt and the western Pacific volcanic belt, which is formed by the squeezing, rising, sinking and rupture of the Pacific plate and the surrounding plates. There are 319 active volcanoes known to be distributed in the Pacific Rim, accounting for 62% of the world's active volcanoes. Of these, 45 per cent are in the Western Pacific Volcanic Belt and 17 per cent in the Eastern Pacific Volcanic Belt. The volcanic rocks in the Pacific Ring Volcanic Belt are mainly the products of neutral magma eruptions, the most common is Andesan rock, which is 150 to 300 km from the trench axis, andesite is distributed in an arc parallel to the trench, forming the so-called "Andesan Rock Line". Moderately acidic magma erupted on the continental side of the Andesan rock line. Such as the formation of andesite rock, rhyolite and so on. On the oceanic side of the line, it is dominated by erupting basal magma, forming basalt.
A Himalayan volcanic belt in the Mediterranean Sea
The Mediterranean Himalayan belt of volcanoes traverses southern Eurasia. There are 94 active volcanoes in this belt, accounting for 18% of the total number of active volcanoes in the world. There are many world-famous volcanoes on the belt, such as Vesuvius, Etna, Urcano and Stromboli in Italy. The rocks formed by the eruption are mainly andesite and basalt.
Mid-Ocean Ridge Volcanic Belt
The mid-ocean ridge spreads out in a W-shaped shape around the world, from the Arctic basin through Iceland to the south Atlantic Ocean, south around the southern tip of Africa and turns north-east to meet the mid-Ridge of the Indian Ocean, the Mid-Ocean Ridge extends north to the northern tip of the African continent to meet the Great Rift Valley, south around Australia to the east, and to the southern end of the Mid-Pacific Ridge. The total length is more than 80,000 km. Volcanoes in the ocean are concentrated in the Rift Valley belt. The distribution of volcanoes in the mid-ocean ridge volcanic belt is uneven, mostly concentrated in the Atlantic Rift Valley. Only 14 active volcanoes have been found in the Mid-Pacific Ridge, which are not as active and frequent as in the Atlantic Rift Valley volcanic belt. The volcanic rocks on the belt are mainly peridotite and basalt.
Most of the volcanoes in our country are Cenozoic volcanic rocks. At present, more than 900 volcanic cones have been found in the territory, most of which are extinct volcanoes since the Tertiary Period. I am a madman obsessed with astronomy, geography, and culture, and I will follow us and share more valuable and practical knowledge in the future.