In short, knowing if a volcano is active, dormant, or extinct is complicated and all comes down to timing. And when it comes to geological features , timing is quite difficult for us mere mortals. Individuals and generations have limited life spans, nations rise and fall, and even entire civilization sometimes bite the dust.
But volcanic formations? They can endure for millions of years! Knowing if there still life in them requires hard work, good record-keeping, and above all immense patience.
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The content is provided for information purposes only. Synthesizing nanomaterials from nature's blueprints 6 hours ago. Can we assume constant C14 to C12 ratio in living tissues? Sep 19, Nevertheless, volcanoes may remain dormant for a long period of time. For instance, the volcanoes of Yellowstone, Toba, and Vesuvius were all thought to be extinct before their historic and devastating eruptions. The same is true of the Fourpeaked Mountain eruption in Alaska in Prior to this, the volcano was thought to be extinct since it had not erupted for over 10, years.
Geologists also employ the category of extinct volcano to refer to volcanoes that have become cut off from their magma supply. There are many examples of extinct volcanoes around the world, many of which are found in the Hawaiian-Emperor Seamount Chain in the Pacific Ocean, or stand individually in some areas. For example, the Shiprock volcano, which stands in Navajo Nation territory in New Mexico, is an example of a solitary extinct volcano.
Edinburgh Castle, located just outside the capitol of Edinburgh, Scotland, is famously located atop an extinct volcano. But of course, determining if a volcano is truly extinct is often difficult, since some volcanoes can have eruptive lifespans that measure into the millions of years.
As such, some volcanologists refer to extinct volcanoes as inactive, and some volcanoes once thought to be extinct are now referred to as dormant. In short, knowing if a volcano is active, dormant, or extinct is complicated and all comes down to timing. And when it comes to geological features, timing is quite difficult for us mere mortals. Individuals and generations have limited life spans, nations rise and fall, and even entire civilization sometimes bite the dust. These are Active, Dormant and Extinct.
Where do Volcanoes occur? The majority of volcanoes occur at plate boundaries. They can occur where plates separate, an example of this is Iceland. Here volcanoes are formed by the North American and Eurasian plates pulling apart. Mount Etna is formed by the subduction of the African plate under the Eurasian plate. The melting of the subducted plate causes an increase in pressure which leads to the formation of a magma chamber and in turn a volcano. Hotspots are caused by magma of increased temperature from a mantle plume.
What causes volcanoes to erupt? Rock from subducted plates melts to form molten magma which pushes its way towards the surface forming a magma chamber. Gasses that have been dissolved in the magma expand causing a massive increase in pressure. As it reaches the surface the pressure is released and an eruption occurs. During an eruption volcanic ash, rock particles, dust, gasses and lava are all ejected. How violent the eruption is depends on the amount of silica present in the magma.
Silica produces a thicker magma that is better at trapping gasses. The more gas present the greater the pressure. Therefore the more silica present in the magma the more violent the eruption will be. Types of lava and their effect on the volcano structure There are two types of lava, acidic and basic. Acidic lava has a high silica content and this makes it thicker. Combined these cause the volcano to have a steep sided cone. These are known as Cone Volcanoes. Basic lava contains less silica, this allows the gasses to escape and gives a runny lava.
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