The two main factors that determine the classification (or type) of a volcano are the explosive nature and the material that is ejected. The material that comes from the volcano determines the shape- which is also a big indicator of the type of volcano. Select a classification below to learn more:
Strato Volcanoes: (also called Composite Volcanoes) are formed by alternating layers of lava and rock fragments. This is the reason they are referred to as composite. Strato-Volcanoes often form impressive, snow-capped peaks which are often exceeding 2500m in height, 1000sq.km in surface, and 400km3 in volume.
Between eruptions they are often so quiet they seem extinct. To witness the start of a great eruption requires luck (if you want to call it that) or very careful surveillance.
Composite volcanoes are characterized by eruptions of andesite and dacite- and usually erupt in an explosive way. This is usually caused by viscous magma. When very viscous magma rises to the surface, it usually clogs the craterpipe, and gas in the craterpipe gets locked up. Therefore, the pressure will increase resulting in an explosive eruption.
Strato-volcanoes are constructed along subduction zones.
Another very common and deadly hazard at most Stratos is called a Lahar. Lahar is an Indonesian word for a mudflow, and most geologists use the term to mean a mudflow on an active volcano. Lahars are dangerous because they move quickly, and often times a small eruption or relatively small rainstorm can generate a huge lahar.
A shield volcano is a large volcano with shallow-sloping sides. The name derives from an Icelandic volcano’s translation whose name means "broad shield", from its resemblance to a warrior's shield. Shield volcanoes are formed by lava flows of low viscosity — lava that flows easily.
Shield volcanoes are almost exclusively basalt, a type of lava that is very fluid when erupted. For this reason these volcanoes are not steep.
Because of the fluidity of the lava, major explosive eruptions do not occur. The most severe explosions occur if water enters a vent, although expanding gases in the magma can produce spectacular fountaining of the low viscosity lava.
Cinder cones are commonly found on the flanks of shield volcanoes, stratovolcanoes, and calderas. The rock fragments, often called cinders or scoria, are glassy and contain numerous gas bubbles because the lava cools so quickly. Cinder cones range in size from tens to hundreds of meters tall. Cinder cones are made of pyroclastic material.
The Caldera- dubbed super volcano by scientists- is a tricky and well hidden volcano. Luckily they can go millions of years without so much as a geyser erupting, but these are the most destructive forces on earth.
They are usually so explosive when they erupt that they end up collapsing in on themselves rather than building any tall structure. Caldera eruptions are sufficient to threaten the extinction of species, and cover huge areas with lava and ash.
They hide very well- Santorini Greece is one of three calderas that form the Minoan Caldera. Yellowstone park is another caldera. This caldera is around 45 miles in diameter and is speculated to be capable of destroying almost all of the US and crippling the entire North American continent if it had a full scale eruption (based on the study of the most recent eruption of 640,000 years ago).
strato volcano
Strato Volcanoes: (also called Composite Volcanoes) are formed by alternating layers of lava and rock fragments. This is the reason they are referred to as composite. Strato-Volcanoes often form impressive, snow-capped peaks which are often exceeding 2500m in height, 1000sq.km in surface, and 400km3 in volume.
Between eruptions they are often so quiet they seem extinct. To witness the start of a great eruption requires luck (if you want to call it that) or very careful surveillance.
Composite volcanoes are characterized by eruptions of andesite and dacite- and usually erupt in an explosive way. This is usually caused by viscous magma. When very viscous magma rises to the surface, it usually clogs the craterpipe, and gas in the craterpipe gets locked up. Therefore, the pressure will increase resulting in an explosive eruption.
Strato-volcanoes are constructed along subduction zones.
Hazards
Strato volcanoes have caused by far the most casualties of any type of volcano. This is for a few reasons: First is that there are so many more strato volcanoes than any of the other types. This means that there will also be lots of people who end up living on the flanks of these volcanoes.Another very common and deadly hazard at most Stratos is called a Lahar. Lahar is an Indonesian word for a mudflow, and most geologists use the term to mean a mudflow on an active volcano. Lahars are dangerous because they move quickly, and often times a small eruption or relatively small rainstorm can generate a huge lahar.
Examples
Mount Hood, Mount Rainier, Mount Shasta, Mount Fugi, Mount Mayon, and Vesuvius.shield volcano
A shield volcano is a large volcano with shallow-sloping sides. The name derives from an Icelandic volcano’s translation whose name means "broad shield", from its resemblance to a warrior's shield. Shield volcanoes are formed by lava flows of low viscosity — lava that flows easily.
Shield volcanoes are almost exclusively basalt, a type of lava that is very fluid when erupted. For this reason these volcanoes are not steep.
Because of the fluidity of the lava, major explosive eruptions do not occur. The most severe explosions occur if water enters a vent, although expanding gases in the magma can produce spectacular fountaining of the low viscosity lava.
Hazards:
There are few hazards concerning shield volcanoes- basic common sense applies: don’t go shake one’s hand. There are a few lava formations in Hawaii that you can't walk on due to the unstability of the hardened lava.Examples:
Shield Volcanoes Kilauea (Hawai'i, US), Mauna Kea (Hawai'i, US), Mauna Loa (Hawai'i, US), Lunar dome (Moon), Olympus Mons (Mars)cinder cone
Cinder cones are commonly found on the flanks of shield volcanoes, stratovolcanoes, and calderas. The rock fragments, often called cinders or scoria, are glassy and contain numerous gas bubbles because the lava cools so quickly. Cinder cones range in size from tens to hundreds of meters tall. Cinder cones are made of pyroclastic material.
Examples:
Paricutin, Cerro Negro, and Sunset Cratercalderas
The Caldera- dubbed super volcano by scientists- is a tricky and well hidden volcano. Luckily they can go millions of years without so much as a geyser erupting, but these are the most destructive forces on earth.
They are usually so explosive when they erupt that they end up collapsing in on themselves rather than building any tall structure. Caldera eruptions are sufficient to threaten the extinction of species, and cover huge areas with lava and ash.
They hide very well- Santorini Greece is one of three calderas that form the Minoan Caldera. Yellowstone park is another caldera. This caldera is around 45 miles in diameter and is speculated to be capable of destroying almost all of the US and crippling the entire North American continent if it had a full scale eruption (based on the study of the most recent eruption of 640,000 years ago).