With its striking steep slopes built up of layers of ash and lava, Mount Fuji is a classic stratovolcano. Mount Fuji in Japan is an entirely different formation. Mauna Loa typifies a shield volcano, which is a huge, gently sloping landform built up of many eruptions of fluid lava. Volcanic landforms have evolved over time as a result of repeated volcanic activity. One can say, for example, that large lava flows erupt from Mauna Loa volcano in Hawaii, referring here to the vent but one can also say that Mauna Loa is a gently sloping volcano of great size, the reference in this case being to the landform. Strictly speaking, the term volcano means the vent from which magma and other substances erupt to the surface, but it can also refer to the landform created by the accumulation of solidified lava and volcanic debris near the vent. ( See the table of the world’s major volcanoes by region.) Great destruction also can result when ash collects on a high snowfield or glacier, melting large quantities of ice into a flood that can rush down a volcano’s slopes as an unstoppable mudflow. One feared phenomenon accompanying some explosive eruptions is the nuée ardente, or pyroclastic flow, a fluidized mixture of hot gas and incandescent particles that sweeps down a volcano’s flanks, incinerating everything in its path. In more violent eruptions, the magma conduit is cored out by an explosive blast, and solid fragments are ejected in a great cloud of ash-laden gas that rises tens of thousands of metres into the air. In other cases, entrapped gases tear the magma into shreds and hurl viscous clots of lava into the air. In some cases, magma rises in conduits to the surface as a thin and fluid lava, either flowing out continuously or shooting straight up in glowing fountains or curtains. Swarms of small earthquakes, which may be caused by a rising plug of dense, viscous magma oscillating against a sheath of more-permeable magma, may also signal volcanic eruptions, especially explosive ones. Sometimes beginning with an accumulation of gas-rich magma (molten underground rock) in reservoirs near Earth’s surface, they can be preceded by emissions of steam and gas from small vents in the ground. Yet, while eruptions are spectacular to watch, they can cause disastrous loss of life and property, especially in densely populated regions of the world. A volcanic eruption is an awesome display of Earth’s power. Volcano, vent in the crust of Earth or another planet or satellite, from which issue eruptions of molten rock, hot rock fragments, and hot gases.
#Liquid notes for live crack how to#
COVID-19 Portal While this global health crisis continues to evolve, it can be useful to look to past pandemics to better understand how to respond today.
Student Portal Britannica is the ultimate student resource for key school subjects like history, government, literature, and more.From tech to household and wellness products. Britannica Explains In these videos, Britannica explains a variety of topics and answers frequently asked questions.This Time in History In these videos, find out what happened this month (or any month!) in history.#WTFact Videos In #WTFact Britannica shares some of the most bizarre facts we can find.
Demystified Videos In Demystified, Britannica has all the answers to your burning questions.Britannica Classics Check out these retro videos from Encyclopedia Britannica’s archives.
0 kommentar(er)
