You have 3 free guides left 😟
Unlock your guides8.2 Volcanic eruptions and their products
5 min read•august 16, 2024
Volcanic eruptions shape our planet's surface and atmosphere. From quiet lava flows to explosive clouds, these events showcase Earth's dynamic nature. Understanding eruption types and products is crucial for predicting and managing volcanic hazards.
Volcanoes produce a variety of materials, including lava, pyroclastic fragments, and gases. These products form unique landforms and impact the environment in both destructive and beneficial ways. Studying volcanic activity helps us grasp Earth's inner workings and their surface expressions.
Types of Volcanic Eruptions
Effusive vs. Explosive Eruptions
Top images from around the web for Effusive vs. Explosive Eruptions
4.1 Plate Tectonics and Volcanism – Physical Geology View original
Is this image relevant?
Magma Composition | Physical Geography View original
Is this image relevant?
Magma Composition | Physical Geography View original
Is this image relevant?
4.1 Plate Tectonics and Volcanism – Physical Geology View original
Is this image relevant?
Magma Composition | Physical Geography View original
Is this image relevant?
1 of 3
Top images from around the web for Effusive vs. Explosive Eruptions
4.1 Plate Tectonics and Volcanism – Physical Geology View original
Is this image relevant?
Magma Composition | Physical Geography View original
Is this image relevant?
Magma Composition | Physical Geography View original
Is this image relevant?
4.1 Plate Tectonics and Volcanism – Physical Geology View original
Is this image relevant?
Magma Composition | Physical Geography View original
Is this image relevant?
1 of 3
- Volcanic eruptions categorized into two main types based on magma and gas behavior during eruption process
- Effusive eruptions involve quiet outpouring of lava onto Earth's surface
- Associated with low-viscosity magmas (basaltic compositions)
- Produce fluid lava flows and fountains
- Explosive eruptions characterized by violent ejection of fragmented material, gases, and ash into atmosphere
- Associated with high-viscosity magmas and high gas content
- Generate and ash clouds
Specific Eruption Types
- Hawaiian eruptions produce fluid lava flows and fountains ()
- Icelandic eruptions create extensive lava fields ()
- Strombolian eruptions feature rhythmic explosions and incandescent cinder ejections ()
- Vulcanian eruptions involve short-lived explosive bursts ()
- Plinian eruptions produce tall eruption columns and widespread ash fall ( 79 AD)
- Peléan eruptions generate pyroclastic flows and lava domes ( 1902)
- Phreatomagmatic eruptions occur when magma interacts with external water
- Form maars and tuff rings ()
- Steam-driven explosions create unique landforms
Measuring Eruption Intensity
- (VEI) quantifies relative explosiveness of eruptions
- Scale ranges from 0 to 8
- Considers ejecta volume, eruption column height, and duration
- VEI 0-1: effusive to gentle (Hawaiian eruptions)
- VEI 2-3: explosive (Strombolian to Vulcanian)
- VEI 4-5: large explosive (Plinian)
- VEI 6-8: colossal (rare super-eruptions like Yellowstone)
Volcanic Products
Lava Flows
- Streams of molten rock pouring out of volcano during eruption
- Types categorized based on surface texture and flow behavior:
- : smooth, ropy surface (Hawaiian volcanoes)
- : rough, jagged surface (Mount Etna)
- : angular fragments on flow surface ()
- Lava flow morphology influenced by viscosity, eruption rate, and topography
- Lava tubes form when surface of flow cools and insulates interior (Thurston , Hawaii)
Pyroclastic Materials
- Solid fragments ejected during explosive eruptions
- Categorized by size:
- Ash: < 2 mm (fine particles that can travel long distances)
- : 2-64 mm (pea to fist-sized fragments)
- : > 64 mm (large fragments, often aerodynamically shaped)
- encompasses all pyroclastic material regardless of size or composition
- form from pyroclastic density currents
- Consist of ash, pumice, and rock fragments
- Can cover large areas ()
Volcanic Gases and Other Products
- Mixture of volatile compounds released during eruptions
- Primarily water vapor, carbon dioxide, and sulfur dioxide
- Lesser amounts of hydrogen sulfide, hydrogen chloride, and hydrogen fluoride
- volcanic mudflows composed of water and volcanic debris
- Occur during or after eruptions
- Pose significant hazards to downstream communities ()
- Volcanic domes form when viscous lava extrudes and piles up near vent
- Steep-sided mounds ()
- Can lead to explosive collapse and pyroclastic flows
Factors Influencing Explosivity
Magma Properties
- crucial for explosivity
- (rhyolitic) generally more viscous and gas-rich
- Lead to more explosive eruptions (Mount St. Helens 1980)
- Dissolved gas content significantly influences explosive potential
- Water vapor, carbon dioxide, and sulfur compounds primary volatiles
- Higher gas content increases likelihood of explosive decompression during ascent
- Magma temperature affects viscosity and gas solubility
- Hotter magmas generally less viscous and potentially less explosive
- Cooler magmas more viscous, trapping gases and increasing explosivity
Ascent and Conduit Dynamics
- Rate of magma ascent impacts and bubble formation
- Rapid ascent promotes explosive behavior due to sudden decompression
- Slow ascent allows gradual degassing, potentially leading to effusive eruptions
- Structure and geometry of volcanic conduit system influence magma flow
- Narrow conduits can increase pressure buildup
- Wide conduits may allow easier gas escape
- Pre-existing crystals in magma increase viscosity
- Provide for gas bubbles
- Enhance potential for explosive eruptions
External Factors
- Interactions between magma and external water sources lead to
- Groundwater, surface water, or ice rapidly generate steam
- eruption (Iceland 1963) example of submarine volcano-water interaction
- influences magma composition and eruption style
- produce more silicic, gas-rich magmas (Ring of Fire volcanoes)
- Hot spots and rift zones often produce more basaltic, less explosive eruptions (Hawaii)
Impacts of Volcanic Eruptions
Immediate Environmental Effects
- Lava flows, pyroclastic flows, and lahars cause direct destruction
- Destroy infrastructure and displace populations
- Mount Vesuvius eruption (79 AD) buried Pompeii and Herculaneum
- Ash fall from explosive eruptions impacts air quality and visibility
- Disrupts transportation systems (2010 Eyjafjallajökull eruption grounded European flights)
- Damages crops and poses health risks to humans and animals
- contribute to acid rain formation
- Impacts ecosystems and water quality in affected areas
- 1783 Laki eruption in Iceland caused widespread crop failures and livestock deaths
Long-term and Global Impacts
- Large-scale eruptions affect global climate
- Injection of ash and aerosols into stratosphere leads to short-term cooling
- 1815 Mount Tambora eruption caused "Year Without a Summer" in 1816
- Volcanic soils highly fertile due to mineral content
- Support rich agriculture in many volcanic regions (Java, Indonesia)
- Creation of new landforms and habitats
- Volcanic islands form new ecosystems (Surtsey, Iceland)
- Lava flows create unique landscapes (Hawaii Volcanoes National Park)
Socioeconomic Consequences
- Significant economic impacts on affected regions
- Disruption of tourism, agriculture, and industry
- 1980 Mount St. Helens eruption caused estimated $1 billion in damages
- Opportunities for geothermal energy development
- Volcanic areas provide sustainable energy sources ()
- Cultural and religious significance of volcanoes
- Shape beliefs and practices of many societies (Mount Fuji in Japan)
- Advancements in volcanology and hazard mitigation
- Improved monitoring and prediction techniques
- Development of evacuation plans and early warning systems
© 2024 Fiveable Inc. All rights reserved.
AP® and SAT® are trademarks registered by the College Board, which is not affiliated with, and does not endorse this website.
