Volcanoes

• The viscosity of magma decreases as the temperature increases

  
• Different types of magma have different viscosities at the same temperature, with komatiite being the least viscous and rhyolite being the most viscous
• A stratovolcano is a conical volcano built up of layers of lava and ash, with lava flowing down the sides and ash being ejected from the volcano

  
• A diagram of a volcano shows different parts like the magma chamber, conduit, vent, and crater, as well as types of volcanic eruptions like Strombolian, Plinian, and Hawaiian

  
• Volcanoes form when magma rises through and ruptures the crust, with the resulting morphology determined by the composition of the erupted magma
• A volcano is composed of a magma chamber, a vent from which lava is extruded, and a conduit connecting the vent to the magma chamber
• Rock solidified within the conduit of a volcano is called a volcanic neck, with the flanks surrounding the conduit composed of pyroclastic material and/or lava flows
• When volcanoes erupt, they eject gas, ash, and other materials into the atmosphere in an eruption column, which can produce pyroclastic deposits
• The viscosity of magma is determined by silica content, temperature, and volatile content, with higher silica content leading to more viscous magma
• Mafic magmas form viscous magmas, while increasingly mafic magmas produce thinner magmas
• The viscosity of a melt decreases with increasing temperature, leading to a less viscous liquid
• The concentration of volatiles in magmas, like H2O and CO2, significantly contributes to the viscosity of the melt
• Shield volcanoes form from low-viscosity basaltic magmas, often erupting effusively and having gently sloping sides
• Composite volcanoes, formed from medium-viscosity andesitic magmas, have explosive eruptions and are composed of lava flows and ejected pyroclastic material
• Cinder cones, formed from tephra ejected during strombolian eruptions, are small volcanoes with steep flanks, often occurring in groups and associated with intraplate volcanism
• The graph shows viscosity versus temperature for various types of magma, where viscosity decreases as temperature increases

  
• A stratovolcano is a conical volcano built up of layers of lava and ash, with lava flowing down the sides and ash ejected from the volcano

  
• The diagram of a volcano illustrates different parts like the magma chamber, conduit, vent, and crater, as well as types of volcanic eruptions such as Strombolian, Plinian, and Hawaiian

  
• Cinder cones develop with the eruption of andesitic to basaltic magma from an initial vent, producing pyroclastic material like scoria and glassy fragments that settle around the vent
• Lava flows travel at different rates depending on viscosity, with basaltic lava flows reaching speeds of 10 km/h, while rhyolitic lavas flow at only a couple of meters per hour
• Basaltic lavas form two main types of lava flows: Pahoehoe (rope-like) flows and A’a flows (rough), with differing appearances due to flow rates affecting the cooling process
• Lava domes are mounds produced by the extrusion of viscous lava, growing as viscous lava piles above existing rock, and can experience explosive eruptions when they partially collapse
• Pyroclastic flows are fast-flowing masses of hot gas and volcanic material produced by explosive eruptions, traveling at speeds up to 700 km/h
• Volcanic eruptions occur when pressure builds up inside the magma chamber due to new lava entering from below or water seeping into the chamber.
• Volcanic eruptions occur when pressure builds up inside the magma chamber due to new lava entering from below or water seeping into the chamber.
• Magma chambers are found beneath volcanic mountains, such as Mount Fujiyama in Japan.
• Volcanic eruptions occur when pressure builds up inside the magma chamber due to new lava entering from below or water seeping into the chamber.
• The magma chamber is the location where molten rock accumulates.
• Magma chambers are found beneath volcanic mountains, such as Mount Fujiyama in Japan.
• The magma chamber is the location where molten rock accumulates.
• Lava flows can be observed during an eruption.
• The movement of tectonic plates causes volcanic activity on land.
• The movement of tectonic plates causes volcanic activity on land.
• The most common type of volcanic eruption is effusive eruption, where lava slowly oozes out of the vent without causing much damage.
• The most common type of volcanic eruption is effusive eruption, where lava slowly oozes out of the vent without causing much damage.
• The magma chamber is where molten rock is stored within the Earth's crust.
• The magma chamber is where molten rock is stored within the Earth's crust.
• Ash clouds can also be seen during an eruption.
• Ash clouds can also be seen during an eruption.
• Ash falls can be dangerous because they contain fine particles that can cause respiratory problems if breathed in.