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The lava flowing from stratovolcanoes typically cools and solidifies before spreading far, due to high viscosity. The magma forming this lava is often felsic , having high to intermediate levels of silica (as in rhyolite , dacite , or andesite ), with lesser amounts of less viscous mafic magma. [ 2 ]
The broad top of Mount Rainier contains three named summits. The highest of these named sub-summits is known as the Columbia Crest, at a recently determined height of 14,389.2 ft (4,386 m). [5] The second highest named summit is Point Success, 14,158 ft (4,315 m), at the southern edge of the summit plateau, atop the ridge known as Success Cleaver.
Pinatubo in the Philippines on 15 June 1991, which produced 5 km 3 (1 cu mi) of dacitic magma, a 40 km (25 mi) high eruption column, and released 17 megatons of sulfur dioxide. [ 46 ] Kelud , Indonesia erupted in 2014 and ejected around 120,000,000 to 160,000,000 cubic metres (4.2 × 10 9 to 5.7 × 10 9 cu ft) volcanic ashes which caused ...
Rhyolite (/ ˈraɪ.əlaɪt / RY-ə-lyte) [1][2][3][4] is the most silica -rich of volcanic rocks. It is generally glassy or fine-grained (aphanitic) in texture, but may be porphyritic, containing larger mineral crystals (phenocrysts) in an otherwise fine-grained groundmass. The mineral assemblage is predominantly quartz, sanidine, and plagioclase.
This high viscosity can be obtained in two ways: by high levels of silica in the magma, or by degassing of fluid magma. Since viscous basaltic and andesitic domes weather fast and easily break apart by further input of fluid lava, most of the preserved domes have high silica content and consist of rhyolite or dacite.
Mount Tambora, or Tomboro, is an active stratovolcano in West Nusa Tenggara, Indonesia. Located on Sumbawa in the Lesser Sunda Islands, it was formed by the active subduction zones beneath it. Before 1815, its elevation reached more than 4,300 metres (14,100 feet) high, making it one of the tallest peaks in the Indonesian archipelago.
A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. The process that forms volcanoes is called volcanism. On Earth, volcanoes are most often found where tectonic plates are diverging or converging, and because most of Earth ...
1879 by G. Beetham and J. P. Maxwell (non-indigenous) Easiest route. Hike. Mount Ruapehu (Māori: [ˈɾʉaˌpɛhʉ]; colloquially / ˈruːəˌpeɪhuː /) is an active stratovolcano at the southern end of the Taupō Volcanic Zone and North Island volcanic plateau in New Zealand. It is 23 km (14 mi) northeast of Ohakune and 23 km (14 mi ...