Shield volcanoes are wide because they are made to function as an island, much to the surprise of many scientists. These volcanoes are enormously big, usually spreading out over 300 miles.
shield,cindercone,composite,extinict
Shield volcanoes may occur far from any plate boundaries.
Both shield volcanoes and cinder cones erupt low-viscosity basaltic lava and have eruptions that are only mildly explosive if at all.Cinder cones are small, steep-sloped volcanoes composed primarily of a chunky variety of basalt called scoria.Shield volcanoes are large, gently sloping volcanoes composed primarily of layers of lava flows.
Composite volcanoes or Stratovolcanoes are your typical cartoon image of volcanoes, very tall, narrow craters at the top, steeper sides often snow capped peaks. Shield volcanoes tend to not be as tall and have much more shallow sloping sides. The reason for this is due to their products and location. Composite volcanoes produce lava which is much more viscous (thicker) than shield volcanoes, which tend to produce a thinner runnier lava. This is due to the Silica (SiO2) content of the lavas. Composite volcanoes tend to be produced by more Acidic lavas (with a higher Silica content) where as shield volcanoes are produced by lavas with a more Basic composition, (a lower silica content). Composite volcanoes (Mt St Helens, Vesuvius, Mt Fugi) tend to be formed near destructive plate boundries where one tectonic plate is being subducted beneath another. When the subducted plate reaches roughly 700 km depth it begins to enter the Aesthenosphere, a layer of more ductile rock deep in the mantle. The water content of the subducted plate causes the aesthenosphere to partially melt. The molten magma begins to rise in plumes towards the surface. As the magma plume rises it has a lot of contact with the surrounding rocks it passes through, and it absorbs silica from them, arriving at the surface as a viscous silica rich melt. Shield volcanoes (Mauna Loa, Kiluea, Hekla) are more common over constructive plate margins where two plates are pulling apart. When the plates pull apart it de-pressurises the mantle beneath the plates and causes it to partially melt. The Magma rises up the cracks between the two retreating plates, with little contact to the surrounding rocks, and so picks up very little silica content. This causes it to reach the surface as a runny basic lava. The runny nature of shield volcanoes means that lava flows travel a long way from the volcano crater, causing little build up on the surrounding flanks of the volcano. The viscous nature of Composite volcanoes means that the lava doesn't travel very far and builds up on the sides of the volcanoes making them much steeper. Shield volcanoes are more often active than composite volcanoes, some erupt near constantly for many decades. Composite volcanoes erupt far less often, and can be mistakenly thought of as being extint for hundreds of years between eruptions. Composite volcanoes tend to have much more explosive eruptions than shield volcanoes, which tend to be more effusive in nature. Composite volcanoes are capable of pyroclastic flows (Mt St Helens) and huge eruptions which can entirely destroy the volcano (Pinatubo, Krakatoa). Shield volcanoes tend to only erupt in lava flows, which can create enormous shallow volcanoes (Mauna Loa, Olympus Mons)
At some places on earth surface thin layers of lava pour out of the vent and hard on top of previous layers
shield volcanoes have cinders that come out then land on it. that's what makes them bigger than cinder cone volcanoes.
Shield Volcanoes - Wide base found at constructive plate margins Composite Volcanoes - Steeper Sides found at Destructive (subduction) margins
shield volcanoes have cinders that come out then land on it. that's what makes them bigger than cinder cone volcanoes.
The Hawaiian islands are made of two types of volcanoes, shield volcanoes and cinder cone volcanoes. Shield volcanoes have broad bases with gentle slopes. Cinder cone volcanoes have steeper sides, are made from fragments of lava, and are usually located at the base of shield volcanoes.
Shield volcanoes are typically formed from basaltic lava flows, which are low in silica content and very fluid. This type of lava allows for the gradual buildup of wide, gently sloping volcanic cones characteristic of shield volcanoes.
Yes, highly liquid lava can form wide shield-like mountains called shield volcanoes. These volcanoes have gentle slopes due to the runny nature of the lava which allows it to flow long distances before solidifying. Shield volcanoes are typically found at divergent plate boundaries and hot spots.
A low, wide-based volcano is called a shield volcano. These types of volcanoes have gentle slopes and are formed by the gradual flow of low-viscosity lava. Examples include Mauna Loa in Hawaii and Iceland's shield volcanoes.
Shield Volcanoes - Wide base found at constructive plate margins Composite Volcanoes - Steeper Sides found at Destructive (subduction) margins
No, shield volcanoes have low viscosity lava due to their composition of basaltic magma, which has low silica content. This low viscosity allows the lava to flow easily and spread out over a wide area, resulting in the gentle, sloping shape characteristic of shield volcanoes.
shield volcanoes have cinders that come out then land on it. that's what makes them bigger than cinder cone volcanoes.
No, shield volcanoes are not steep mountains. They have gently sloping sides due to the relatively low viscosity of the lava that flows from them, which allows the lava to spread out and create a wide, shield-like shape.
shield volcanoes