Understanding the different types of volcanoes and their characteristics provides insight into Earth’s geology, aids in hazard prediction and risk management, and helps us to appreciate the dynamic nature of the planet we inhabit.
How Many Types of Volcanoes Are There?
How many types of volcanoes there are depends on who you ask. The three main types of volcanoes are cinder cones, composite volcanoes (stratovolcanoes) and shield volcanoes. Lava domes are a common fourth type of volcano. However, there are other kinds of volcanoes, plus they are compound or complex volcanoes that have features of multiple types. For example, Trident Volcano in Alaska is a complex volcano that include stratovolcanoes and lava domes.
Main Types of Volcanoes
The types of volcanoes vary according to their size and how they erupt. Cinder cones often erupt only once, composite volcanoes erupt infrequently, and shield volcanoes erupt the most often. Cinder cones erupt rocks and gas, without flowing lava. Composite volcanoes erupt thick lava and rocks, while shield volcanoes erupt fluid lava.
Cinder Cones (Scoria Cones)
Cinder cones are the simplest and most common type of volcano. They form as a single eruption vent expels volcanic debris, including ash, cinders, and volcanic rocks. The accumulation of debris forms the cone shape.
- Description: Smallest type, steep sides built from loose volcanic debris from single eruption vent.
- Examples: Paricutin in Mexico
- Size: Generally less than 400 meters tall.
- Magma Composition: Basaltic to andesitic.
- Eruption Frequency: May erupt only once.
Composite Volcanoes (Stratovolcanoes)
Composite volcanoes or stratovolcanoes have the classic “volcano” shape. They are tall, symmetrical cones. Stratovolcanoes form by the accumulation of different types of volcanic materials, including lava, ash, and rock. Their eruptions can be violent.
- Description: Large, symmetrical, steep-sided mountains formed by layers of lava, ash, and volcanic rocks.
- Examples: Mount Fuji in Japan, Mount St. Helens in the United States
- Size: Up to several kilometers in height.
- Magma Composition: Andesitic to rhyolitic.
- Eruption Frequency: Less frequent, more explosive than cinder cones.
The largest volcanoes are shield volcanoes. These colossal volcanoes boast gentle sloping sides created by the flow of highly fluid basaltic lava. Their eruptions produce extensive lava flows.
- Description: Large, broad, gentle slopes formed by fluid basaltic lava flows.
- Examples: Mauna Loa, Mauna Kea, and Kilauea in Hawaii; Olympus Mons on Mars
- Size: Several kilometers in height and up to 100 km wide.
- Magma Composition: Basaltic.
- Eruption Frequency: Frequent, less explosive eruptions.
Lava Domes (Volcanic Domes)
Lava domes form by the slow oozing of highly viscous lava. They are smaller formations, with steep sides, and often form within the craters of larger volcanoes.
- Description: Small, steep-sided mounds where viscous lava piles up near the vent.
- Examples: Mount St. Helens Lava Dome
- Size: Usually less than 500 meters tall.
- Magma Composition: Rhyolitic or dacitic.
- Eruption Frequency: Variable, usually within the context of larger eruptions.
Other Types of Volcanoes
- Formed by bulging of the volcanic edifice rather than eruptions.
- Extremely large volcanic systems.
- Examples: Yellowstone Caldera in the USA
- Located beneath the ocean.
- Examples: Loihi Seamount in Hawaii
- Found under ice caps.
- Examples: Öræfajökull in Iceland
- Eject mud, water, and gases.
- Examples: Lusi mud volcano in Indonesia
Cryovolcanoes (Ice Volcanoes)
While there are no ice volcanoes on Earth, they exist elsewhere.
- Erupt volatile materials like water or ammonia.
- Examples: Found on Pluto and some moons in our solar system.
Volcanoes in the Solar System
Earth is not the only planet in the solar system with volcanoes:
- Moon: No current activity, but indications of past eruptions
- Mars: Olympus Mons (shield volcano)
- Venus: Numerous shield volcanoes
- Io (Jupiter’s moon): Hundreds of active volcanoes
- Enceladus (Saturn’s moon): Cryovolcanoes
Categories of Volcanoes
- Active: An active volcano either is erupting or has a history of recent activity. Earthquake swarms, ground inflation, and carbon dioxide/sulfur dioxide release are indications of activity. Kilauea is an example of an active volcano.
- Dormant: A dormant volcano shows no signs of recent activity, but has potential for erupting in the future. Yellowstone is a dormant volcano. Even though it is an active geothermal site, it goes around 700,000 years between eruptions.
- Extinct: An extinct volcano no long has a magma supply. Shiprock in New Mexico is an example of the remains of an extinct volcano.
Types of Volcanic Eruptions
The broad types of volcanic eruptions are magmatic, phreatomagmatic, and phreatic, but vulcanologists subdivide eruptions either by names or numbers. The Volcanic Explosivity Index (VEI) ranges from 0 for a Hawaiian-type (shield volcano eruption) to an 8 for a supervolcano eruption.
- Involves the eruption of magma, mainly from decompression of gases.
- Fluid lava flows, effusive.
- Examples: Mauna Loa in Hawaii.
- Mildly explosive, lava fountains and gas bursts.
- Examples: Mount Stromboli in Italy.
- Explosive eruptions producing ash and volcanic bombs.
- Examples: Sakurajima in Japan.
- Eruption with pyroclastic flows.
- Examples: Mount Pelée in Martinique.
- Extremely explosive, large amounts of ash and gas.
- Examples: Mount Vesuvius in Italy.
- Interaction of magma with water, explosive.
- Examples: Taal Volcano in the Philippines.
- Steam-driven eruptions or rock without magma.
- Examples: Mount Ontake in Japan.
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