How are composite volcanoes formed GCSE?
Composite Volcanoes (Stratovolcano) Composite volcanoes are the most deadly of volcano types. They are made of alternate layers of ash and lava and have steep sides built up by eruptions of intermediate viscosity andesitic lava and explosive tephra.
Where would composite volcanoes form?
Composite volcanoes are some of the most dangerous volcanoes on the planet. They tend to occur along oceanic-to-oceanic or oceanic-to-continental boundaries because of subduction zones. They tend to be made of felsic to intermediate rock and the viscosity of the lava means that eruptions tend to be explosive.
How are composite volcanoes formed ks2?
Stratovolcanoes are called composite volcanoes because they made from a series of eruptions that have occurred over thousands of years. The eruptions that form these volcanoes lay down alternating layers of lava, ash, cinders and pyroclastic material.
How composite volcano formed in their distinctive shapes?
The essential feature of a composite volcano is a conduit system through which magma from a reservoir deep in the Earth's crust rises to the surface. The volcano is built up by the accumulation of material erupted through the conduit and increases in size as lava, cinders, ash, etc., are added to its slopes.
How are composite volcanoes formed at destructive plate boundaries?
Destructive plate boundaries The point at which one plate is forced beneath the other is called the subduction zone. The plate then melts, due to friction, to become molten rock (magma). The magma then forces its way up to the side of the plate boundary to form a volcano.
How are shield and composite volcanoes formed?
Composite volcanoes are usually found at destructive plate margins. Examples of composite volcanoes include Mount Fuji (Japan), Mount St Helens (USA) and Mount Pinatubo (Philippines). Shield volcanoes are low with gently sloping sides and are formed from layers of lava. Eruptions are typically non-explosive.
What materials make up composite volcanoes?
Composite volcanoes—also called stratovolcanoes—are named for their composition. These volcanoes are built from layers, or strata, of pyroclastic material, including lava, pumice, volcanic ash, and tephra. The layers stack on each other with each eruption.
What is the main characteristics of a composite volcano?
Composite volcanoes consist of alternating layers of ash and lava flows. Known also as strato volcanoes, their shape is a symmetric cone with steep sides that rise as high as 8,000 feet. They form along Earth's subduction zones where one tectonic plate pushes beneath another.
What eruption forms a composite volcano?
Composite volcanoes form in subduction zones when an oceanic plate subducts beneath a continental plate. The volcanoes often contain more than one type of lava. Andesite is the main type of lava that creates stratovolcanoes. Stratovolcano is another name for composite volcanoes.
How volcanoes are formed at convergent boundaries?
As the sinking plate moves deeper into the mantle, fluids are released from the rock causing the overlying mantle to partially melt. The new magma (molten rock) rises and may erupt violently to form volcanoes, often building arcs of islands along the convergent boundary.
How are volcanoes formed by plate tectonics?
On land, volcanoes form when one tectonic plate moves under another. Usually a thin, heavy oceanic plate subducts, or moves under, a thicker continental plate. When this happens, the ocean plate sinks into the mantle.
What is the characteristics of composite volcano?
Composite volcanoes consist of alternating layers of ash and lava flows. Known also as strato volcanoes, their shape is a symmetric cone with steep sides that rise as high as 8,000 feet. They form along Earth's subduction zones where one tectonic plate pushes beneath another.
What are the characteristics of composite volcano?
Composite volcanoes consist of alternating layers of ash and lava flows. Known also as strato volcanoes, their shape is a symmetric cone with steep sides that rise as high as 8,000 feet. They form along Earth's subduction zones where one tectonic plate pushes beneath another.
What type of magma makes a composite volcano?
Composite volcanoes usually erupt a range of compositions from basalt to rhyolite, but intermediate (andesitic) and dacitic magmas are most common. Mount Rainier has less compositional diversity than many composite cones as it consists of mostly andesitic lava flows and lahar deposits.
How volcanoes are formed by tectonic plates?
On land, volcanoes form when one tectonic plate moves under another. Usually a thin, heavy oceanic plate subducts, or moves under, a thicker continental plate. When this happens, the ocean plate sinks into the mantle.
How is a volcano formed it is formed when?
A volcano is formed when hot molten rock, ash and gases escape from an opening in the Earth's surface. The molten rock and ash solidify as they cool, forming the distinctive volcano shape shown here. As a volcano erupts, it spills lava that flows downslope.
What is the magma composition of a composite volcano?
Composite volcano magma is felsic, which means it contains silicate-rich minerals rhyolite, andesite, and dacite. Low-viscosity lava from a shield volcano, such as might be found in Hawaii, flows from fissures and spreads.
What is the meaning of composite volcano?
A composite volcano, also known as a stratovolcano is a cone-shaped volcano built from several layers of lava, pumice, ash, and tephra. Due to its viscous lava, a composite volcano tends to form tall peaks rather than rounded cones. Mount Fuji in Japan and Mount Shasta in California are examples of composite volcanoes.