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Questions and Answers
In 1991, Mount Pinatubo erupted in the Philippines, ejecting 10 km³ of material into the atmosphere. What is the name of the local deity that the Aetas believe lives in the mountain?
In 1991, Mount Pinatubo erupted in the Philippines, ejecting 10 km³ of material into the atmosphere. What is the name of the local deity that the Aetas believe lives in the mountain?
Apung Pinatubo
What is the process called in which magma, which is buoyant against rock, rises to the surface and becomes lava?
What is the process called in which magma, which is buoyant against rock, rises to the surface and becomes lava?
What is the term for the process that occurs when volatiles are added to rocks, resulting in melting into magma?
What is the term for the process that occurs when volatiles are added to rocks, resulting in melting into magma?
What is the name for a region of abnormally high temperature known as a hot spot, which triggers anatexis of the overlying oceanic or continental plate?
What is the name for a region of abnormally high temperature known as a hot spot, which triggers anatexis of the overlying oceanic or continental plate?
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The Hawaiian Islands and the Emperor Seamount Chain represent an example of ocean island basalts.
The Hawaiian Islands and the Emperor Seamount Chain represent an example of ocean island basalts.
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Which volcano classification is NOT characterized by its shape?
Which volcano classification is NOT characterized by its shape?
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Lava dome mounds are roughly circular. These domes form when ______ lava cannot flow too far due to the viscosity and cools into a mound.
Lava dome mounds are roughly circular. These domes form when ______ lava cannot flow too far due to the viscosity and cools into a mound.
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Shield volcanoes are broad, gently sloping mounds shaped like a ______
Shield volcanoes are broad, gently sloping mounds shaped like a ______
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What is the name for the layer of solidified volcanic material that forms around a conduit?
What is the name for the layer of solidified volcanic material that forms around a conduit?
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Composite volcanoes, also known as stratovolcanoes, are tall, steep, ______ mountains.
Composite volcanoes, also known as stratovolcanoes, are tall, steep, ______ mountains.
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What are the smaller, steeper mounds composed of tephra, which represent the remnants of explosive eruptions, called?
What are the smaller, steeper mounds composed of tephra, which represent the remnants of explosive eruptions, called?
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Which of the following is NOT considered a type of eruption?
Which of the following is NOT considered a type of eruption?
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What is the name given to the small, steep mounds composed of tephra or volcanic fragments formed by explosive eruptions?
What is the name given to the small, steep mounds composed of tephra or volcanic fragments formed by explosive eruptions?
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What type of eruption produces lava flows exclusively, typically involving low-viscosity lavas?
What type of eruption produces lava flows exclusively, typically involving low-viscosity lavas?
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Which of the following is the primary cause of explosive eruptions?
Which of the following is the primary cause of explosive eruptions?
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Which eruption type usually occurs in a shallow body of water, producing strong explosions as a result of magma coming into contact with water?
Which eruption type usually occurs in a shallow body of water, producing strong explosions as a result of magma coming into contact with water?
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Which type of eruption results from the extreme buildup of gases in the magma chamber, leading to a column of debris and ash that can reach more than 10 km high?
Which type of eruption results from the extreme buildup of gases in the magma chamber, leading to a column of debris and ash that can reach more than 10 km high?
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Which eruption type results from the collapse of the eruption column into an incandescent pyroclastic flow?
Which eruption type results from the collapse of the eruption column into an incandescent pyroclastic flow?
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Which eruption type originates from viscous lava which slows down bubble formation and clogs up conduits, leading to build-up of pressure that causes an eruption column of 5-10 km?
Which eruption type originates from viscous lava which slows down bubble formation and clogs up conduits, leading to build-up of pressure that causes an eruption column of 5-10 km?
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Which eruption type is characterized by sustained fissure eruptions, which produce curtains of basaltic lava, and often result in the formation large igneous provinces?
Which eruption type is characterized by sustained fissure eruptions, which produce curtains of basaltic lava, and often result in the formation large igneous provinces?
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Which type of eruption is characterized by the bursting of clumps of gas bubbles at the surface, resulting in incandescent lava flows and pyroclastic debris, with an eruption column less than 5 km high?
Which type of eruption is characterized by the bursting of clumps of gas bubbles at the surface, resulting in incandescent lava flows and pyroclastic debris, with an eruption column less than 5 km high?
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The eruption of Mount Vesuvius, which destroyed Pompeii and Herculaneum, is an example of a Vulcanian eruption.
The eruption of Mount Vesuvius, which destroyed Pompeii and Herculaneum, is an example of a Vulcanian eruption.
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Which type of eruption is characterized by the violent thermal contraction of magma as it interacts with water, resulting in an explosion?
Which type of eruption is characterized by the violent thermal contraction of magma as it interacts with water, resulting in an explosion?
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Which type of eruption is driven purely by steam generated in a volcanic source?
Which type of eruption is driven purely by steam generated in a volcanic source?
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The type of eruption a volcano experiences is dependent on its size and shape.
The type of eruption a volcano experiences is dependent on its size and shape.
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What are the primary products of volcanic eruptions, which consist of molten rock materials that have risen to the surface?
What are the primary products of volcanic eruptions, which consist of molten rock materials that have risen to the surface?
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Volcanic glass is a type of volcanic rock that forms when lava cools quickly, preventing crystal formation.
Volcanic glass is a type of volcanic rock that forms when lava cools quickly, preventing crystal formation.
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What is the name given to the elongated, rod-like features that are formed as lava flows solidify, perpendicular to the direction of flow, creating hexagonal patterns?
What is the name given to the elongated, rod-like features that are formed as lava flows solidify, perpendicular to the direction of flow, creating hexagonal patterns?
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Which type of lava produces the wrinkled, billowing, or ropey surface texture characteristic of pahoehoe flows?
Which type of lava produces the wrinkled, billowing, or ropey surface texture characteristic of pahoehoe flows?
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What is the name given to the rough, broken, and rubble-like surface texture characteristic of aʼaʻ flows?
What is the name given to the rough, broken, and rubble-like surface texture characteristic of aʼaʻ flows?
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When basaltic lava flows rapidly underwater, it is squeezed into blobs, called ______ lavas.
When basaltic lava flows rapidly underwater, it is squeezed into blobs, called ______ lavas.
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What type of volcanic flow is characterized by high viscosity and tends to form mounds rather than flowing far distances?
What type of volcanic flow is characterized by high viscosity and tends to form mounds rather than flowing far distances?
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What type of volcanic flow is known for its low viscosity and often forms lava domes?
What type of volcanic flow is known for its low viscosity and often forms lava domes?
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What type of volcanic flow is characterized by its extreme viscosity, which makes it flow slowly and often forms domes?
What type of volcanic flow is characterized by its extreme viscosity, which makes it flow slowly and often forms domes?
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The term "volcanoclastic deposit" refers exclusively to the fragments of lava that have been ejected from a volcano during an eruption.
The term "volcanoclastic deposit" refers exclusively to the fragments of lava that have been ejected from a volcano during an eruption.
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What is the name given to the solid, solidified volcanic fragments that are ejected from a volcano, typically during explosive eruptions?
What is the name given to the solid, solidified volcanic fragments that are ejected from a volcano, typically during explosive eruptions?
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What is the name for the solid, frothy, mafic tuff that forms from the cooling of volcanic ash and lapilli, often with a bubbly appearance?
What is the name for the solid, frothy, mafic tuff that forms from the cooling of volcanic ash and lapilli, often with a bubbly appearance?
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What is the name for the welded tuff, a solidified and cemented deposit of volcanic ash that is formed by the heat of a pyroclastic flow?
What is the name for the welded tuff, a solidified and cemented deposit of volcanic ash that is formed by the heat of a pyroclastic flow?
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Lahars are a type of volcanic flow that occurs when volcanic ash mixes with enough water to form a viscous slurry.
Lahars are a type of volcanic flow that occurs when volcanic ash mixes with enough water to form a viscous slurry.
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What are the gases that are released from magma during volcanic eruptions, which can range from water vapor to carbon dioxide and hydrogen sulfide?
What are the gases that are released from magma during volcanic eruptions, which can range from water vapor to carbon dioxide and hydrogen sulfide?
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Volatiles are essential for driving the majority of explosive eruptions as they create pressure build-up that is released through the explosion.
Volatiles are essential for driving the majority of explosive eruptions as they create pressure build-up that is released through the explosion.
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What is the primary source of geothermal energy?
What is the primary source of geothermal energy?
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What is the area where groundwater transfers heat from a source to a heat sink, serving as the basis for exploitation of geothermal energy?
What is the area where groundwater transfers heat from a source to a heat sink, serving as the basis for exploitation of geothermal energy?
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What is the name given to the hot, mineralized fluids that are found in geothermal reservoirs?
What is the name given to the hot, mineralized fluids that are found in geothermal reservoirs?
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What is the term used to describe the wells that are drilled into the geothermal reservoir for extracting hot fluids?
What is the term used to describe the wells that are drilled into the geothermal reservoir for extracting hot fluids?
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What is the term for the process of injecting cold water back into the ground to replenish the geothermal reservoir after extraction of hot fluids?
What is the term for the process of injecting cold water back into the ground to replenish the geothermal reservoir after extraction of hot fluids?
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Geothermal energy is renewable, sustainable, and generally considered environmentally friendly.
Geothermal energy is renewable, sustainable, and generally considered environmentally friendly.
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The Philippines, being a country with active volcanoes, has a significant geothermal resource potential, which is why it is one of the leading producers of geothermal energy in the world.
The Philippines, being a country with active volcanoes, has a significant geothermal resource potential, which is why it is one of the leading producers of geothermal energy in the world.
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The Philippines has built a large number of geothermal power plants, utilizing its geothermal resource base.
The Philippines has built a large number of geothermal power plants, utilizing its geothermal resource base.
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What is the name of the largest geothermal power plant in the Philippines, located in Tongonan, Leyte?
What is the name of the largest geothermal power plant in the Philippines, located in Tongonan, Leyte?
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Which of the following is a consequence of using geothermal energy that can pose environmental risks?
Which of the following is a consequence of using geothermal energy that can pose environmental risks?
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A volcanic ______ is any vent or built-up mountain where lava, pyroclastic materials, or gases erupt.
A volcanic ______ is any vent or built-up mountain where lava, pyroclastic materials, or gases erupt.
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Divergent boundaries occurring between two oceanic plates are known as ______ volcanoes.
Divergent boundaries occurring between two oceanic plates are known as ______ volcanoes.
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Arcs growing on continents are known by this term: ______.
Arcs growing on continents are known by this term: ______.
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The region of abnormally high temperature created by intraplate volcanism is known as a ______.
The region of abnormally high temperature created by intraplate volcanism is known as a ______.
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Many successive flood basalt eruptions can form a ______ of lava flows.
Many successive flood basalt eruptions can form a ______ of lava flows.
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At divergent boundaries, volcanism manifests as ridges or fissures where lavas erupt and produce ______ melting.
At divergent boundaries, volcanism manifests as ridges or fissures where lavas erupt and produce ______ melting.
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The suite of magmas typically produced at convergent boundaries is known for being highly ______.
The suite of magmas typically produced at convergent boundaries is known for being highly ______.
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______ volcanism creates a series of eruptions that are characterized by the outpouring of large amounts of lava.
______ volcanism creates a series of eruptions that are characterized by the outpouring of large amounts of lava.
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Lava that is silica-depleted and has a low viscosity is called ______.
Lava that is silica-depleted and has a low viscosity is called ______.
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The volcanic flows characterized by an intermediate viscosity and forming mounds are known as ______.
The volcanic flows characterized by an intermediate viscosity and forming mounds are known as ______.
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The most silica-enriched volcanic flows are referred to as ______ flows.
The most silica-enriched volcanic flows are referred to as ______ flows.
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Lava tubes are conduits within flows that allow the interior to remain hot and ______.
Lava tubes are conduits within flows that allow the interior to remain hot and ______.
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Pahoehoe is a type of lava flow that has a ______ surface texture.
Pahoehoe is a type of lava flow that has a ______ surface texture.
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When basaltic lava flows underwater, it is shaped into blobs known as ______ lavas.
When basaltic lava flows underwater, it is shaped into blobs known as ______ lavas.
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The unique structure formed from the cooling and contraction of lava into hexagonal columns is called ______.
The unique structure formed from the cooling and contraction of lava into hexagonal columns is called ______.
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As pahoehoe cools and increases in viscosity, it can evolve into ______ flow.
As pahoehoe cools and increases in viscosity, it can evolve into ______ flow.
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Magma accumulates underground in an open space known as a ______ vent.
Magma accumulates underground in an open space known as a ______ vent.
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The Philippine Institute of Volcanology and Seismology (PHIVOLCS) monitors volcanic hazards in the ______.
The Philippine Institute of Volcanology and Seismology (PHIVOLCS) monitors volcanic hazards in the ______.
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Low-viscosity lava can form ______ volcanoes, which are broad and gently sloping.
Low-viscosity lava can form ______ volcanoes, which are broad and gently sloping.
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The need to classify volcanoes is essential for assessing ______ risks.
The need to classify volcanoes is essential for assessing ______ risks.
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Multiple pyroclastic cones can form from one eruptive ______.
Multiple pyroclastic cones can form from one eruptive ______.
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In the case of lava flows, viscosity refers to the ______ of the lava.
In the case of lava flows, viscosity refers to the ______ of the lava.
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Lahars form when volcanic ash mixes with enough ______ to create a slurry.
Lahars form when volcanic ash mixes with enough ______ to create a slurry.
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The process in which magma rises to the surface and becomes ______ is known as volcanism.
The process in which magma rises to the surface and becomes ______ is known as volcanism.
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The eruption of Mount Pinatubo in 1991 is an example of a significant ______ event.
The eruption of Mount Pinatubo in 1991 is an example of a significant ______ event.
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At divergent boundaries, volcanism manifests as ridges or ______ where lavas erupt.
At divergent boundaries, volcanism manifests as ridges or ______ where lavas erupt.
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Divergent boundaries mostly occur between two ______ plates.
Divergent boundaries mostly occur between two ______ plates.
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Volcanism at mid-ocean ridges accounts for the production of new oceanic ______.
Volcanism at mid-ocean ridges accounts for the production of new oceanic ______.
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Decompression melting occurs when portions of Earth's mantle move to an area of lower ______.
Decompression melting occurs when portions of Earth's mantle move to an area of lower ______.
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Most eruptions occur along plate ______, while some occur at intraplate hot spots.
Most eruptions occur along plate ______, while some occur at intraplate hot spots.
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Volcanism is influenced by plate interactions at their ______.
Volcanism is influenced by plate interactions at their ______.
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Magma becomes ______ when it rises and erupts through a volcano.
Magma becomes ______ when it rises and erupts through a volcano.
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__________ eruptions are sustained fissure eruptions, producing curtains of basaltic lava.
__________ eruptions are sustained fissure eruptions, producing curtains of basaltic lava.
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__________ eruptions produce low-viscosity basaltic lava flows and fountains.
__________ eruptions produce low-viscosity basaltic lava flows and fountains.
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__________ eruptions are the result of the bursting of clumps of gas bubbles at the surface.
__________ eruptions are the result of the bursting of clumps of gas bubbles at the surface.
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__________ eruptions result from more viscous lava, which slows down bubble formation and clogs up conduits.
__________ eruptions result from more viscous lava, which slows down bubble formation and clogs up conduits.
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__________ eruptions result from the extreme buildup of gases in the magma chamber and conduit.
__________ eruptions result from the extreme buildup of gases in the magma chamber and conduit.
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__________ are purely steam-driven, caused by the expansion of water into steam when heated by a nearby magma chamber or volcanic source.
__________ are purely steam-driven, caused by the expansion of water into steam when heated by a nearby magma chamber or volcanic source.
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Over time, Hawaiian eruptions produce __________ volcanoes.
Over time, Hawaiian eruptions produce __________ volcanoes.
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Prolonged Icelandic eruptions produce __________.
Prolonged Icelandic eruptions produce __________.
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Plinian eruptions result from the extreme buildup of gases in the magma chamber and conduit, which become as much as ______% gas.
Plinian eruptions result from the extreme buildup of gases in the magma chamber and conduit, which become as much as ______% gas.
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Peléan eruptions are characterized by nuée ardente or 'glowing ______,' which result from the collapse of the eruption column.
Peléan eruptions are characterized by nuée ardente or 'glowing ______,' which result from the collapse of the eruption column.
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Vulcanian eruptions result from more viscous lava, which slows down bubble formation and clogs up ______.
Vulcanian eruptions result from more viscous lava, which slows down bubble formation and clogs up ______.
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Strombolian eruptions result from the bursting of clumps of gas bubbles at the surface, throwing up clots of ______.
Strombolian eruptions result from the bursting of clumps of gas bubbles at the surface, throwing up clots of ______.
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Hawaiian eruptions produce low-viscosity basaltic lava flows and ______.
Hawaiian eruptions produce low-viscosity basaltic lava flows and ______.
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A Surtseyan eruption occurs in a shallow body of water, characterized by strong ______ as magma comes in contact with water.
A Surtseyan eruption occurs in a shallow body of water, characterized by strong ______ as magma comes in contact with water.
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Phreatomagmatic eruptions are driven by the violent thermal contraction of magma when it interacts with ______.
Phreatomagmatic eruptions are driven by the violent thermal contraction of magma when it interacts with ______.
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Icelandic eruptions produce curtains of basaltic ______.
Icelandic eruptions produce curtains of basaltic ______.
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Study Notes
Unit 15: Understanding Volcanoes
- Volcanoes are openings in the Earth's surface from which lava, gases, and pyroclastic materials erupt.
- Volcanism is the process by which magma rises to the surface.
- Volcanoes form in different settings like divergent boundaries, convergent boundaries, and hotspots.
- They are classified based on their structure and activity.
- Different types of volcanoes include shield volcanoes, composite volcanoes, cinder cones, and lava domes.
- Volcanic eruptions produce various materials like lava, ash, tephra, and gases; these can be cinders or lapilli.
- Eruptions can be classified as effusive or explosive based on the type of material erupted and its explosiveness; different styles exist like Hawaiian, Strombolian, Plinian, and Peléan.
- The geothermal gradient is the rate of temperature increase with depth beneath the Earth's surface, typically around 30°C per kilometer.
- Geothermal energy can be harnessed from volcanic areas for human use; power plants use the heat to generate electricity.
- PHIVOLCS (Philippine Institute of Volcanology and Seismology) monitors volcanic activity in the Philippines; the organization uses a classification system for volcanoes, focusing on those with a higher risk of eruption.
- The Philippines is in a geologically active area, meaning there are many volcanoes, located in the “Ring of Fire”.
- The classification system for volcanoes helps identify areas with higher risk potential, enabling better preparedness for volcanic hazards.
- Volcanic eruptions can produce different types of debris like pyroclastic flows, and ash blankets, which can solidify into tuff, ignimbrite, or other materials.
- Different volcanic eruptions have distinctly different results with varied compositions and viscosity.
Essential Questions
- Volcanoes are important in understanding Earth's processes and in maintaining the Earth's internal energy balance.
- Understanding volcanoes helps us better prepare for volcanic hazards and harness volcanic energy for human use; this includes managing associated risks and developing strategies that utilize the energy for human benefit.
Review
- Plate tectonics theory states that Earth's lithosphere is broken into plates, and their interactions at the boundaries lead to different processes and landforms.
- Plate boundaries include divergent, convergent, and transform boundaries.
- Magma is molten rock material; lava is magma on the Earth's surface.
- Volcanic activity is linked to plate tectonics; understanding these forces is essential to understand volcanic processes.
Lesson 15.1: Volcanoes
- Volcanoes form when magma rises to the surface and erupts; the process is driven by various factors including degassing, pressure, and changes in the geothermal gradient.
- Understanding geological processes like plate tectonics helps to understand the cause of eruptions.
- An activity, "Volcano in a Beaker," can demonstrate how eruptions might occur; this can illustrate the interplay of heat, pressure, and the release of gases within a model eruption.
Lesson 15.2: Types of Volcanoes Based on Structure
- There are different types of mounds that volcanoes can form with varying shapes and heights; these are often based on viscosity, composition, and eruptive style.
- This activity illustrates differences in the shape, height, and slope of various volcano types using clay and illustration board; this visual representation allows for better comprehension of the different structural characteristics of volcanoes.
Lesson 15.3: Active and Inactive Volcanoes
- Active volcanoes have eruptive histories, meaning there's been a recorded eruption.
- Potentially active volcanoes, while not having recent recorded eruptions, exhibit features indicating history of volcanic activity.
- Inactive volcanoes have no eruptive history and will not erupt again.
- The Philippines has 23 active volcanoes and is identified as a region in the Ring of Fire, which places the country in a geologically active area.
- Different volcanoes exhibit different types of eruptions; monitoring activity and classifying types can better assist in understanding and managing risk.
Lesson 15.4: Volcanic Eruptions
- Volcanic eruptions can be classified based on their eruptive style, explosivity, the volume of debris, and the height of the resulting column; using the Volcanic Explosivity Index (VEI) better categorizes volcanic events.
- Eruptions can be effusive (lava flows) or explosive (pyroclastic flows), leading to vastly differing types and impacts.
- Magmatic eruptions, phreatic eruptions, or phreatomagmatic eruptions are driven by different, often interacting, processes.
Lesson 15.5: Materials Emitted from Volcanic Eruptions
- Primary volcanic products are lava and pyroclastic materials.
- Lava can be basaltic, rhyolitic, or andesitic, and its viscosity influences its flow characteristics.
- Pyroclastic materials are fragments of rock and lava ejected during an eruption. These can include different materials (ash, cinders, lapilli) and in different forms like glass or blocks.
- The different materials, whether lava or pyroclastic fragments, exhibit variations in their properties based on a variety of factors like structure, composition, and origin; this can result in diverse forms and impacts.
Lesson 15.6: Harnessing Volcanic Energy
- Geothermal energy is the internal heat of the Earth.
- Volcanoes are often situated in areas of high geothermal gradients.
- Geothermal areas and power plants use the heat to generate electricity or to heat buildings.
- Geothermal resources are renewable, relatively safe, and cheap but can have environmental consequences like water contamination or subsidence.
- The different types of volcanic materials and structures are tied to the different types and properties of the geothermal fluids.
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Explore the fascinating world of volcanoes in Unit 15. This quiz covers volcanic formations, eruptive processes, and the various types of volcanoes. Test your understanding of volcanism and its impact on the Earth's landscape.
