What is a stratovolcano?

A stratovolcano is a cone-shaped volcanic landform created over thousands of years from successive eruptions and layers of volcanic material. They have gentle slopes at the base that rise quickly to form tall peaks near the summit and are typically located above subduction zones, often as part of volcanically active regions like the Ring of Fire. Stratovolcanoes consist of overlapping layers of ash, mud, solidified lava flows, volcanic domes, and pyroclastic material. Due to this layering, they are also known as composite volcanoes. The steep slopes are vulnerable to lahars, avalanches, and landslides. More than 700 volcanoes are classified as stratovolcanoes.

How is a stratovolcano different from other types of volcanoes?

Stratovolcanoes are cone-shaped volcanoes built up over thousands of years by multiple eruptions. Unlike shield volcanoes that have faster-moving, less-viscous lava, stratovolcanoes feature cooler, more viscous lavas, such as andesite and dacite, that pile up around the vent. The steep slopes of stratovolcanoes are vulnerable to lahars, avalanches, and landslides. There are more stratovolcanoes than any other type of volcano.

What are the main parts or layers of a stratovolcano?

A stratovolcano, also called a composite volcano, develops over thousands of years through repeated eruptions and other volcanic activity. Stratovolcanoes are complex formations composed of uneven, overlapping layers of: * Ash * Mud * Solidified lava flows * Volcanic domes * Pyroclastic material Typically, a stratovolcano has one primary vent near its peak, often located within a crater . Other vents include fumaroles, which emit gas and vapor. During an eruption, a large section of rock above a magma chamber may give way, causing the chamber to collapse and form a large bowl-shaped volcanic depression called a caldera .

How do stratovolcanoes form and grow over time?

Stratovolcanoes, also called composite volcanoes, are created over thousands of years through recurring volcanic activity . They are formed from layers of ash, solidified lava flows, mud, volcanic domes, and pyroclastic material, which are mixtures of hot rock fragments and gases. The steep slopes of stratovolcanoes are vulnerable to avalanches, lahars and landslides because of their composite structure. Andesite and dacite rocks are common in stratovolcanoes and produce thick extrusions that pile up on volcanic deposits near the vent. Multiple eruptions over extended periods result in tall, cone-shaped peaks.

Why can eruptions from stratovolcanoes be especially dangerous?

Eruptions from stratovolcanoes can be especially dangerous due to a combination of factors. Stratovolcanoes are known for explosive eruptions because they tend to have viscous, gas-rich magma. The high gas content in the magma, combined with its viscosity, leads to intense explosions that shatter the magma into pyroclastic fragments . These eruptions can generate pyroclastic flows , which are dense mixtures of hot volcanic fragments and gas that move rapidly down the slopes, sweeping away and incinerating everything in their path. Additionally, the steep slopes and composite structure of stratovolcanoes make them prone to lahars (mudflows of volcanic material), avalanches, and landslides, which can travel great distances and impact communities far from the volcano.

Can you name some famous stratovolcanoes and explain how they have impacted their surrounding environment?

Stratovolcanoes, also called composite volcanoes, are known for their steep, conical shape formed from layers of ash, lava flows, and pyroclastic material. Several famous stratovolcanoes have had a significant impact on their surrounding environments: Mount Vesuvius The eruption in 79 C.E. buried Pompeii and Herculaneum, causing immense destruction and loss of life. Mount Pinatubo The 1991 eruption injected large amounts of sulfur dioxide into the stratosphere, which formed an aerosol of tiny sulfate droplets that circled the globe and reduced solar radiation reaching Earth's surface. The event is believed to have caused a temporary cooling of the Earth's climate. Mount Ruiz In 1985, the eruption of Mount Ruiz caused mudflows that destroyed the city of Armero, Colombia, killing over 25,000 people. Mount Saint Helens In 1980, an earthquake triggered a landslide and lateral air blast, causing widespread destruction of forests and killing 57 people. These eruptions demonstrate the destructive potential of stratovolcanoes, with impacts ranging from local devastation to global climate disruption.

stratovolcano

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Momotombo Volcano and Momotombito Island, Nicaragua

Cross-sectional diagram showing three tectonic plates at ocean ridges, transform faults, and a subduction zone. The image illustrates rising magma forming rift and subduction volcanoes, convection currents in the mantle, and features such as ocean trenches, extinct and hot-spot volcanoes, and the movement of plates above a molten core and low-velocity mantle layer.

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Also called:: composite volcano

Related Topics:: volcano; andesite; caldera; dacite; subduction zone

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Mount Fuji Field of green tea growing near Fuji, Shizuoka prefecture, Japan, with Mount Fuji rising in the background.

stratovolcano

geology

Also known as: composite cone volcano, composite volcano

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Last updated

Sep. 26, 2026 •History

Top Questions

What is a stratovolcano?
A stratovolcano is a cone-shaped volcanic landform created over thousands of years from successive eruptions and layers of volcanic material. They have gentle slopes at the base that rise quickly to form tall peaks near the summit and are typically located above subduction zones, often as part of volcanically active regions like the Ring of Fire.

Stratovolcanoes consist of overlapping layers of ash, mud, solidified lava flows, volcanic domes, and pyroclastic material. Due to this layering, they are also known as composite volcanoes. The steep slopes are vulnerable to lahars, avalanches, and landslides. More than 700 volcanoes are classified as stratovolcanoes.
2 Britannica Sources
1. volcano: Stratovolcanoes
2. stratovolcano: Development and features
Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.
How is a stratovolcano different from other types of volcanoes?
Stratovolcanoes are cone-shaped volcanoes built up over thousands of years by multiple eruptions. Unlike shield volcanoes that have faster-moving, less-viscous lava, stratovolcanoes feature cooler, more viscous lavas, such as andesite and dacite, that pile up around the vent. The steep slopes of stratovolcanoes are vulnerable to lahars, avalanches, and landslides. There are more stratovolcanoes than any other type of volcano.
2 Britannica Sources
1. volcano: Stratovolcanoes
2. stratovolcano: Development and features
Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.
What are the main parts or layers of a stratovolcano?
A stratovolcano, also called a composite volcano, develops over thousands of years through repeated eruptions and other volcanic activity.

Stratovolcanoes are complex formations composed of uneven, overlapping layers of:
* Ash
* Mud
* Solidified lava flows
* Volcanic domes
* Pyroclastic material

Typically, a stratovolcano has one primary vent near its peak, often located within a crater. Other vents include fumaroles, which emit gas and vapor.

During an eruption, a large section of rock above a magma chamber may give way, causing the chamber to collapse and form a large bowl-shaped volcanic depression called a caldera.
3 Britannica Sources
Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.
How do stratovolcanoes form and grow over time?
Stratovolcanoes, also called composite volcanoes, are created over thousands of years through recurring volcanic activity. They are formed from layers of ash, solidified lava flows, mud, volcanic domes, and pyroclastic material, which are mixtures of hot rock fragments and gases.

The steep slopes of stratovolcanoes are vulnerable to avalanches, lahars and landslides because of their composite structure. Andesite and dacite rocks are common in stratovolcanoes and produce thick extrusions that pile up on volcanic deposits near the vent. Multiple eruptions over extended periods result in tall, cone-shaped peaks.
3 Britannica Sources
Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.
Why can eruptions from stratovolcanoes be especially dangerous?
Eruptions from stratovolcanoes can be especially dangerous due to a combination of factors. Stratovolcanoes are known for explosive eruptions because they tend to have viscous, gas-rich magma. The high gas content in the magma, combined with its viscosity, leads to intense explosions that shatter the magma into pyroclastic fragments.

These eruptions can generate pyroclastic flows, which are dense mixtures of hot volcanic fragments and gas that move rapidly down the slopes, sweeping away and incinerating everything in their path. Additionally, the steep slopes and composite structure of stratovolcanoes make them prone to lahars (mudflows of volcanic material), avalanches, and landslides, which can travel great distances and impact communities far from the volcano.
3 Britannica Sources
Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.
Can you name some famous stratovolcanoes and explain how they have impacted their surrounding environment?
Stratovolcanoes, also called composite volcanoes, are known for their steep, conical shape formed from layers of ash, lava flows, and pyroclastic material. Several famous stratovolcanoes have had a significant impact on their surrounding environments:
- Mount Vesuvius The eruption in 79 C.E. buried Pompeii and Herculaneum, causing immense destruction and loss of life.
- Mount Pinatubo The 1991 eruption injected large amounts of sulfur dioxide into the stratosphere, which formed an aerosol of tiny sulfate droplets that circled the globe and reduced solar radiation reaching Earth's surface. The event is believed to have caused a temporary cooling of the Earth's climate.
- Mount Ruiz In 1985, the eruption of Mount Ruiz caused mudflows that destroyed the city of Armero, Colombia, killing over 25,000 people.
- Mount Saint Helens In 1980, an earthquake triggered a landslide and lateral air blast, causing widespread destruction of forests and killing 57 people.
These eruptions demonstrate the destructive potential of stratovolcanoes, with impacts ranging from local devastation to global climate disruption.
5 Britannica Sources
Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

stratovolcano, volcanic landform characterized by a conical shape formed by layers of volcanic material deposited during successive volcanic eruptions. Stratovolcanoes tend to slope gently at the base but rise quickly near the summit to form tall mountain peaks. They are typically found above subduction zones, and they are often part of large volcanically active regions, such as the Ring of Fire that frames much of the Pacific Ocean. There are more than 700 known volcanoes classified as stratovolcanoes, many more than any other volcanic formation. Several are among the best-known volcanoes because of their striking appearance and their notoriety for some of the most-spectacular eruptions in history.

Development and features

Stratovolcanoes develop over many thousands of years through repeated eruptions and other volcanic activity. They are among the most-complex volcanic formations, and a single stratovolcano may be composed of mixed layers of ash, mud, solidified lava flows, volcanic domes (large hill-like bulges of solidified magma), and pyroclastic material (fluidized mixtures of hot rock fragments and gases that move rapidly down slopes). Because these layers are deposited in uneven overlapping concentrations rather than in neat strata, many scientists prefer the term composite volcano.

This unevenness of deposition allows for the development of several vents from which gas and magma can escape. Typically, a stratovolcano has one primary vent near its peak. This vent is often located within a crater, where material has been blasted away during one or more previous eruptions. The crater may be filled with water or ice, or it may contain a volcanic dome during a period of relative inactivity. Craters are often unstable features, with the location of the vent changing over time. Other vents associated with the volcano include fumaroles, which emit gas and vapour.

Eruption examples

Several of the most-famous volcanic disasters in history resulted from the eruptions of stratovolcanoes. The eruptions of Mount Vesuvius (79 ce), Mount Tambora (1815), Krakatoa (1883), Novarupta (1912), and Mount Pinatubo (1991) caused tremendous damage, loss of life, and climatic disruption. The 1985 eruption of Mount Ruiz, a stratovolcano in Colombia’s Cordillera Central, melted the volcano’s snowcap and sent downslope great mudflows that destroyed the city of Armero and killed more than 25,000 people.