Volcanology Part 1 (Anatomy, Classification, Eruption Types of Volcanoes) Flashcards
The study of volcanoes and its materials and processes.
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A person who engages in the study of volcanology.
Volcanologist
A naturally occurring landform produced where lava erupts onto Earth’s surface.
Volcano
Lighter materials tends to ____? Especially if there is no pressure hindering it.
Rise
Where do Volcanoes erupt?
Pacific Ring of Fire
Hotspots
Spreading Centers
a 40,000 km-long zone bordering much of the Pacific Plate and tracing the boundaries of the Indo-Australian, Philippine, North American, Juan de Fuca, Cocos, Caribbean, Nazca, and South American Plates.
Pacific Ring of Fire
The surface manifestation of hot mantle plumes rising from the mantle, which is believed to originate from the boundary of the mantle and outer core.
Hotspots
Mantle plumes originally have “heads” which intrude and create ____? It is a large expanse of area which resulted from voluminous outflow of basaltic lava that can last up to millions of years.
Flood Basalts
When these mantle plumes intrude in the middle of plates, what happens?
Can result in a trail of volcanoes and can leave the older trails extinct as it progresses.
Hotspot Classification
- Core-mantle boundary origin
- Upper mantle origin
- Lithospheric origin
What is the reason why there is a trail of islands in Hawaii?
Due to the Pacific plate moving over a mantle plume (hot spot)
Regions where divergent plate boundaries spread and produce juvenile magma material, creating submarine volcanoes.
Spreading Centers
An opening on a volcano where a conduit or a pipe terminates.
Vent
A circular pipe where magma movement is localized.
Conduit
A funnel-shaped depression found at the summit of most volcanoes.
Crater
A small cone-shaped volcano formed from a flank eruption from the main volcano.
Parasitic Cone
A large underground region of magma that supplies the volcano.
Magma Chamber
According to the shape of the volcano
Morphology
According to the eruptive history of a volcano
Activity and HIstory
The local and international classification for volcanoes
Local - PHIVOLCS
International - USGS
Classifications of Volcanoes
Shield Volcano
Stratovolcano
Pyroclastic Cone
Caldera*
Supervolcano*
Produced by the accumulation of fluid basaltic lavas and exhibit the shape of a broad, slightly domed structured that resembles a warrior’s shield, 15 degrees or less.
Shield Volcano
Also called composite volcanoes, built from interlayered tephra and lava flows. Gradually sloping, 10 to 30 degrees and considered as most dangerous and eruptive.
Stratovolcano
Composed mostly of loose ejected ash, and some lava, appearing relatively symmetrical and steeply built, with large, deep craters, with most being produced by a single eruptive event.
Pyroclastic Cones
Dominantly composed of vesicular, basaltic material.
Scoria Cones
Composed of various compositions.
Cinder Cones
A large depression, >1km in diameter, typically caused by collapse of the summit area of a volcano following a violent eruption, or due to depletion of the magma chamber.
Caldera
A volcano that had an eruptive history that reached VEI 8.
Supervolcano
A massive caldera complex in Wyoming, USA, famous for its supervolcano eruptions primarily due to it being hotspot that produces due to it being hotspot that produces acidic magma and lava.
Yellowstone Supervolcano
Classification of Volcanoes (PHIVOLCS)
Active Volcano
Potentially Active Volcano
Inactive Volcano
Had a recorded eruption for the past 600 years, and has datable material since 10,000 years ago.
Active Volcano
Geomorphologically young volcano that is currently not erupting, but is supposed to erupt again.
Potentially Active Volcano
Has not had an eruption for at least 10,000 years, and is not expected to erupt again in a comparable time scale of the future.
Inactive Volcano
Classification of Volcanoes (USGS)
Active Volcano
Dormant Volcano
Extinct Volcano
Difference of the three classification (USGS)
Active Volcano - Had at least one eruption in the past 10,000 years.
Dormant Volcano - No historically recorded eruption or had not erupted in thousands of years, but is likely to erupt in the future.
Extinct Volcano - Had not erupted within recorded history.
A systematic classification of volcanic eruptions based on observations during an eruption.
VEI (Volcanology Explosivity Index)
What is included in the VEI
Tephra volume (m³)
Column height
Eruption type
Description
Duration
Quiet eruptions
Effusive
Loud eruptions
Explosive
Magma-driven
Magmatic
Steam-driven
Phreatic
Combination of Magmatic and Phreatic
Phreatomagmatic
Effusive, quiet eruptions that produce large volumes of very hot, thin, runny lava and extrudes via fissures.
Icelandic
Are similar with Icelandic eruptions, effusive eruptions of large volumes of very hot, thin, runny lava but originates from vents of the volcanoes.
Hawaiian
Are more explosive eruptions that shoot thicker lava along with a burst of steam, gas and ash that spatters molten lava.
Strombolian
Are series of discrete, loud eruptions in “throat-clearing,” canon-like explosions that shoots high velocity blocks, and bombs.
Vulcanian
Also called Nuée Ardente eruptions, occur when large amount of tephra, gas, and lava are erupted laterally from the crater, producing “glowing” avalanches.
Pelean
are very large, explosive eruptions that involves very viscous magma and produce very large volumes of ash and tephra that can cover a very wide area.
Plinian
Occur when water is heated even without contact with magma, and erupts as a mixture of hot water and steam. A common example occurs with geysers
Phreatic
also called Surtseyan, are explosive eruptions that occur when water interacts with magma and violently bursts into steam and volumes of ash.
Phreatomagmatic
