Podcast
Questions and Answers
Match the volcano type with its typical relative danger level:
Match the volcano type with its typical relative danger level:
Cinder Cone Volcano = Not very dangerous. Shield Volcano = A little danger. Composite Volcano (Stratovolcano) = Very dangerous. Caldera Forming Volcano = Extremely Dangerous
Match the following volcanic features with their relative silica content and viscosity:
Match the following volcanic features with their relative silica content and viscosity:
Si-rich Magmas = Thick and viscous. Si-poor Magmas = Thin and runny. High Viscosity = Less flow Low Viscosity = More flow
Match the Volcanic Explosivity Index (VEI) with its corresponding eruption type
Match the Volcanic Explosivity Index (VEI) with its corresponding eruption type
VEI 0 = Hawaiian VEI 4 = Pelean/Plinian VEI 7 = Plinian/Ultra-Plinian (super-colossal) VEI 8 = Ultra-Plinian (mega-colossal)
Match the following descriptions to their corresponding volcanic hazards:
Match the following descriptions to their corresponding volcanic hazards:
Match the following descriptions to their volcanic activity classifications:
Match the following descriptions to their volcanic activity classifications:
Match each volcano with its most notable characteristic
Match each volcano with its most notable characteristic
Match the type of volcanic hazard with its primary cause of mortality:
Match the type of volcanic hazard with its primary cause of mortality:
Link the methods used in volcanic eruption prediction with the phenomena they measure:
Link the methods used in volcanic eruption prediction with the phenomena they measure:
Associate each volcanic region with a volcano found in the region:
Associate each volcanic region with a volcano found in the region:
Match the following supervolcanic eruptions with an effect of the eruption:
Match the following supervolcanic eruptions with an effect of the eruption:
Match each class of eruption with its specific characteristics:
Match each class of eruption with its specific characteristics:
Differentiate between the forms of volcanic forecast:
Differentiate between the forms of volcanic forecast:
Match the effects from volcano eruptions with climate:
Match the effects from volcano eruptions with climate:
Relate the types of volcano with their magma properties:
Relate the types of volcano with their magma properties:
Match the name given to lava when it first appears, with its name when it reaches the surface.
Match the name given to lava when it first appears, with its name when it reaches the surface.
Categorize which locations are known for having gentle eruptions, and explosive.
Categorize which locations are known for having gentle eruptions, and explosive.
Match the hazards that volcanoes can create with other events:
Match the hazards that volcanoes can create with other events:
Associate the areas when volcanoes are most likely to be dangerous.
Associate the areas when volcanoes are most likely to be dangerous.
Match each of the following processes that lead to rock to melting.
Match each of the following processes that lead to rock to melting.
Match the following classes of volcanic activity with their most appropriate descriptor:
Match the following classes of volcanic activity with their most appropriate descriptor:
Determine which of the natural disasters will occur given certain volcanic phenomena:
Determine which of the natural disasters will occur given certain volcanic phenomena:
Match the scientists to a role of what they do.
Match the scientists to a role of what they do.
Volcanologists take measures to prepare people, categorize what measures are taken for preparation.
Volcanologists take measures to prepare people, categorize what measures are taken for preparation.
Match each of the eruptions class' name with its defining characteristics:
Match each of the eruptions class' name with its defining characteristics:
Match the eruption hazard to what is the best type precaution that can be taken to increase life safety:
Match the eruption hazard to what is the best type precaution that can be taken to increase life safety:
Scientists have found ways to predict earthquakes, can you associate what each one measures?
Scientists have found ways to predict earthquakes, can you associate what each one measures?
Match the cause with one of the indirect things that can cause deaths from volcanoes:
Match the cause with one of the indirect things that can cause deaths from volcanoes:
Match the process named by the term what that process does.
Match the process named by the term what that process does.
Can you associate common materials or items with their hazard?
Can you associate common materials or items with their hazard?
There are positive results for when volcanoes erupt. Determine if it is a negative or a positive outcome.
There are positive results for when volcanoes erupt. Determine if it is a negative or a positive outcome.
Match the eruption with one of the possible descriptions.
Match the eruption with one of the possible descriptions.
Match the terms defined when magma forms:
Match the terms defined when magma forms:
There are areas with active volcanoes, can you correctly associate where each of these volcanoes is located?
There are areas with active volcanoes, can you correctly associate where each of these volcanoes is located?
Match the event with its potential effect?
Match the event with its potential effect?
Can you make an association with a scientist's role and their defined scientific purpose with volcanoes?
Can you make an association with a scientist's role and their defined scientific purpose with volcanoes?
Associate each of the eruption types with what type of volcano results from that event.
Associate each of the eruption types with what type of volcano results from that event.
Correctly name each of the steps related to volcanic activity which are important to watch for:
Correctly name each of the steps related to volcanic activity which are important to watch for:
Match the eruption to the number of deaths and main reason for the cause of them.
Match the eruption to the number of deaths and main reason for the cause of them.
Match each of the types of volcano classifications.
Match each of the types of volcano classifications.
As the material is underground called magma, they are defined, please match the following.
As the material is underground called magma, they are defined, please match the following.
Match the type of volcano with its typical eruption style:
Match the type of volcano with its typical eruption style:
Match the volcanic hazard with its description:
Match the volcanic hazard with its description:
Match the description with the class of volcano activity:
Match the description with the class of volcano activity:
Match the process with its effect on magma composition:
Match the process with its effect on magma composition:
Match the eruption type with its characteristics:
Match the eruption type with its characteristics:
Match the term with its definition related to the danger posed by magma:
Match the term with its definition related to the danger posed by magma:
Match the geographic area with its volcanic setting:
Match the geographic area with its volcanic setting:
Match the volcano monitoring method with what it measures:
Match the volcano monitoring method with what it measures:
Match the effect with the volcanic gas responsible:
Match the effect with the volcanic gas responsible:
Match the eruption magnitude with the Volcanic Explosivity Index (VEI):
Match the eruption magnitude with the Volcanic Explosivity Index (VEI):
Match the term with the type of volcanic eruption it describes:
Match the term with the type of volcanic eruption it describes:
Match the Canadian volcanic area with its geographic location:
Match the Canadian volcanic area with its geographic location:
Match the historical eruption with its primary cause of death:
Match the historical eruption with its primary cause of death:
Match the prediction method with the specific phenomenon it monitors:
Match the prediction method with the specific phenomenon it monitors:
Match the supervolcano with a key feature:
Match the supervolcano with a key feature:
Match the rock type with its silica content
Match the rock type with its silica content
Match the eruption type with its tectonic setting
Match the eruption type with its tectonic setting
Match the definitions below with the proper term:
Match the definitions below with the proper term:
Match the definition with the feature shown in the eruption:
Match the definition with the feature shown in the eruption:
Match the cause of jökulhaups below:
Match the cause of jökulhaups below:
Match the area with examples of geothermal harnessing:
Match the area with examples of geothermal harnessing:
Match the following concepts:
Match the following concepts:
Match with the amount of Pyroclastic Material:
Match with the amount of Pyroclastic Material:
Which statement would be made in USGS Circular 1073:
Which statement would be made in USGS Circular 1073:
What actions are taken to minimize Volcano hazards:
What actions are taken to minimize Volcano hazards:
Match the Volcano to what it is associated with:
Match the Volcano to what it is associated with:
Match the name of the Volcano with the outcome:
Match the name of the Volcano with the outcome:
With the composition of magma and the volcanoes, which makes less explosive volcanoes and in what geographical location?
With the composition of magma and the volcanoes, which makes less explosive volcanoes and in what geographical location?
Match the following about the 1980 Eruption with the correct descriptor:
Match the following about the 1980 Eruption with the correct descriptor:
Match the Tsunami's causes:
Match the Tsunami's causes:
Match the reason with the location that volcanic erruptions can be found:
Match the reason with the location that volcanic erruptions can be found:
Match the process with the description:
Match the process with the description:
Match the caldera-forming steps below:
Match the caldera-forming steps below:
Match the VEI rating with the example volcano with it:
Match the VEI rating with the example volcano with it:
Match the name with the eruption characteristics below:
Match the name with the eruption characteristics below:
Match the areas with the correct type of Volcano
Match the areas with the correct type of Volcano
Which is the deadliest volcanic eruption and its VEI:
Which is the deadliest volcanic eruption and its VEI:
What is the most significant challenge in determining the likelihood of a volcanic eruptions?
What is the most significant challenge in determining the likelihood of a volcanic eruptions?
Which factor most significantly influences whether a volcanic eruption will be explosive or gentle?
Which factor most significantly influences whether a volcanic eruption will be explosive or gentle?
What is the primary reason scientists monitor volcanic gas emissions, such as sulfur dioxide (SO₂) and carbon dioxide (CO₂)?
What is the primary reason scientists monitor volcanic gas emissions, such as sulfur dioxide (SO₂) and carbon dioxide (CO₂)?
Why can volcanic activity cause intense lightning storms?
Why can volcanic activity cause intense lightning storms?
Which of the following statements best describes the role of magma viscosity in determining the danger posed by a volcano?
Which of the following statements best describes the role of magma viscosity in determining the danger posed by a volcano?
Beyond the immediate vicinity of a volcano, what secondary volcanic hazard often poses the most significant threat to human populations and infrastructure?
Beyond the immediate vicinity of a volcano, what secondary volcanic hazard often poses the most significant threat to human populations and infrastructure?
How does the addition of volatiles, such as water or carbon dioxide, contribute to the formation of magma?
How does the addition of volatiles, such as water or carbon dioxide, contribute to the formation of magma?
Which of the following scenarios would most likely result in a phreatic explosion?
Which of the following scenarios would most likely result in a phreatic explosion?
What is the cause of death associated with the eruption of Laki, Iceland (1783)?
What is the cause of death associated with the eruption of Laki, Iceland (1783)?
Of the following volcanoes, which eruption would be classified as mega-colossal?
Of the following volcanoes, which eruption would be classified as mega-colossal?
How do scientists use changes in a volcano's slope before a volcanic eruption?
How do scientists use changes in a volcano's slope before a volcanic eruption?
What is the most common type of volcanic hazard?
What is the most common type of volcanic hazard?
What is the name given to the type of eruption that occurs when volcanoes erupt under a glacier and melts the ice?
What is the name given to the type of eruption that occurs when volcanoes erupt under a glacier and melts the ice?
What primary factor dictates magma's density, viscosity, and temperature?
What primary factor dictates magma's density, viscosity, and temperature?
What type of magma leads to explosive volcanoes and is typically found in continental crust?
What type of magma leads to explosive volcanoes and is typically found in continental crust?
How do volcanoes affect climate?
How do volcanoes affect climate?
What is the best technique, in combination, to predict eruptions?
What is the best technique, in combination, to predict eruptions?
What is the difference between volcanic forecasts and volcanic predictions?
What is the difference between volcanic forecasts and volcanic predictions?
Which of the following would be an example of a long-term prediction technique?
Which of the following would be an example of a long-term prediction technique?
Which area sees gentle eruptions?
Which area sees gentle eruptions?
What is the main risk formed by cinder cone eruptions?
What is the main risk formed by cinder cone eruptions?
What is the most dangerous type of volcano?
What is the most dangerous type of volcano?
What is the VEI of an eruption with super-colossal description?
What is the VEI of an eruption with super-colossal description?
What volume of ejecta is present with a VEI of index 5?
What volume of ejecta is present with a VEI of index 5?
Which volcano caused deaths due to Volcano Collapse?
Which volcano caused deaths due to Volcano Collapse?
A volcano that is determined to eject > 1000 km³ of pyroclastic material, is given what term?
A volcano that is determined to eject > 1000 km³ of pyroclastic material, is given what term?
What event will immediately follow a supervolcano?
What event will immediately follow a supervolcano?
What event is Yellowstone known for?
What event is Yellowstone known for?
Rocks begin to melt when what is added to them?
Rocks begin to melt when what is added to them?
Which of the following is an example of a geographical location where magma with less silica would make less explosive volcanoes?
Which of the following is an example of a geographical location where magma with less silica would make less explosive volcanoes?
Which volcano has an intermediate silica content?
Which volcano has an intermediate silica content?
An eruption with a plume height of > 25 km, would be classified as having what VEI?
An eruption with a plume height of > 25 km, would be classified as having what VEI?
How much ejecta volume is associated with a eruption that is classified 'gentle'?
How much ejecta volume is associated with a eruption that is classified 'gentle'?
How do animals die in the Ashfall Fossil Beds State Historical Park, Nebraska?
How do animals die in the Ashfall Fossil Beds State Historical Park, Nebraska?
What secondary effect can Caldera creation trigger?
What secondary effect can Caldera creation trigger?
If structures, crops, and plants catch fire, what hazard would cause that?
If structures, crops, and plants catch fire, what hazard would cause that?
In the 1980 Mount St. Helens eruption, how did structures collapse?
In the 1980 Mount St. Helens eruption, how did structures collapse?
For short term prediction, what gases are most important to monitor?
For short term prediction, what gases are most important to monitor?
What is the main positive outcome of volcanoes?
What is the main positive outcome of volcanoes?
In North America, what risk could eruptions have?
In North America, what risk could eruptions have?
Match the volcanic hazard with its primary triggering mechanism:
Match the volcanic hazard with its primary triggering mechanism:
Match each volcano type with its characteristic silica content in magma:
Match each volcano type with its characteristic silica content in magma:
Match the listed Volcanic Explosivity Index (VEI) values to their corresponding ejecta volume ranges:
Match the listed Volcanic Explosivity Index (VEI) values to their corresponding ejecta volume ranges:
Match each method of predicting volcanic eruptions with its primary measurement:
Match each method of predicting volcanic eruptions with its primary measurement:
Match each type of volcanic eruption with its primary characteristics:
Match each type of volcanic eruption with its primary characteristics:
Match the tectonic setting with the typical magma composition found there.
Match the tectonic setting with the typical magma composition found there.
Match major volcanic gases with their primary environmental impacts:
Match major volcanic gases with their primary environmental impacts:
Match the term with its description related to magma formation processes:
Match the term with its description related to magma formation processes:
Match the volcanic feature with its formation process:
Match the volcanic feature with its formation process:
Match the volcanic location with its primary tectonic setting:
Match the volcanic location with its primary tectonic setting:
Match each type of volcanic rock with its approximate silica (SiO₂) content:
Match each type of volcanic rock with its approximate silica (SiO₂) content:
Match the term with its description related to volcanic cone types:
Match the term with its description related to volcanic cone types:
Match the listed volcano with the primary cause of death during its deadliest eruption:
Match the listed volcano with the primary cause of death during its deadliest eruption:
Match volcanic hazards with the most effective mitigation strategy
Match volcanic hazards with the most effective mitigation strategy
Match the volcanic term with its precise definition concerning tephra.
Match the volcanic term with its precise definition concerning tephra.
Link the following volcanic prediction techniques to the instrumentation used:
Link the following volcanic prediction techniques to the instrumentation used:
Correlate the type of Magmatic eruption with the viscosity of the material erupted
Correlate the type of Magmatic eruption with the viscosity of the material erupted
Match the volcanic benefit with its implementation
Match the volcanic benefit with its implementation
Match each specific volcanic area in Canada with its corresponding geographical location within the country:
Match each specific volcanic area in Canada with its corresponding geographical location within the country:
Match the impact of volcanic eruptions to human population with their respective effects:
Match the impact of volcanic eruptions to human population with their respective effects:
Match the following terms relating to the impact of volcanic eruptions on the climate with their respective descriptions:
Match the following terms relating to the impact of volcanic eruptions on the climate with their respective descriptions:
In the context of volcano monitoring and risk assessment, correlate the following terms with their appropriate application or impact:
In the context of volcano monitoring and risk assessment, correlate the following terms with their appropriate application or impact:
Match specific geologic features with their direct tectonic relationship
Match specific geologic features with their direct tectonic relationship
Correlate terms used in volcanology with their characteristics
Correlate terms used in volcanology with their characteristics
Correlate various volcano monitoring technologies with the specific volcanic activity tracked
Correlate various volcano monitoring technologies with the specific volcanic activity tracked
Match characteristics of magma that influence volcano eruptions
Match characteristics of magma that influence volcano eruptions
Match descriptions of types of magma flow following an eruption
Match descriptions of types of magma flow following an eruption
Relate impacts post eruption and methods to mitigate.
Relate impacts post eruption and methods to mitigate.
Match VEI Levels with potential damage level:
Match VEI Levels with potential damage level:
Match the following monitoring approaches with their technological implementation
Match the following monitoring approaches with their technological implementation
In the context of volcanic processes and hazards, match the specific cause and effects
In the context of volcanic processes and hazards, match the specific cause and effects
Match the characteristics with volcanic eruptions
Match the characteristics with volcanic eruptions
Relate the features and description in caldera forming events
Relate the features and description in caldera forming events
Match different scales of time to a predictive task
Match different scales of time to a predictive task
Impact in volcano monitoring
Impact in volcano monitoring
Relate aspects of human behavior with disaster response
Relate aspects of human behavior with disaster response
Impact from volcanic activity.
Impact from volcanic activity.
Relate effects with the scale of volcanic events.
Relate effects with the scale of volcanic events.
Relate volcano topography with hazard analysis:
Relate volcano topography with hazard analysis:
Relate risk assessment with communication strategies:
Relate risk assessment with communication strategies:
Supervolcano description with environmental impacts:
Supervolcano description with environmental impacts:
What critical factor determines whether a volcano, previously classified as dormant, is reclassified as active?
What critical factor determines whether a volcano, previously classified as dormant, is reclassified as active?
Why is accurately defining the time factor for volcano activity classes (active, dormant, extinct) a significant challenge in volcanology?
Why is accurately defining the time factor for volcano activity classes (active, dormant, extinct) a significant challenge in volcanology?
How does incorporating water into magma influence the potential for explosive volcanic eruptions?
How does incorporating water into magma influence the potential for explosive volcanic eruptions?
Which combination of factors would lead to the highest probability of a highly explosive volcanic eruption?
Which combination of factors would lead to the highest probability of a highly explosive volcanic eruption?
Under what circumstance might a shield volcano pose more of a significant danger than its typical gentle eruptions would suggest?
Under what circumstance might a shield volcano pose more of a significant danger than its typical gentle eruptions would suggest?
What is the key difference between volcanic forecasts and predictions, and why is this distinction critical in volcanic risk management?
What is the key difference between volcanic forecasts and predictions, and why is this distinction critical in volcanic risk management?
How does understanding the historic/geologic record of a volcano improve long-term predictive capabilities and risk mitigation strategies?
How does understanding the historic/geologic record of a volcano improve long-term predictive capabilities and risk mitigation strategies?
Why is monitoring volcanic gas emissions, specifically sulfur dioxide (SO₂) and carbon dioxide (CO₂), crucial for short-term eruption prediction?
Why is monitoring volcanic gas emissions, specifically sulfur dioxide (SO₂) and carbon dioxide (CO₂), crucial for short-term eruption prediction?
What is a key link between volcanoes/eruptions and tsunamis, and why is it a significant hazard?
What is a key link between volcanoes/eruptions and tsunamis, and why is it a significant hazard?
How do volcanic eruptions increase the risk of landslides, and why are these secondary events particularly dangerous?
How do volcanic eruptions increase the risk of landslides, and why are these secondary events particularly dangerous?
In what specific way does ashfall from a volcanic eruption lead to the collapse of structures? Provide a possible situation in which collapse is most likely to occur.
In what specific way does ashfall from a volcanic eruption lead to the collapse of structures? Provide a possible situation in which collapse is most likely to occur.
What crucial role do volcanic earthquakes play in forecasting eruptions, especially for volcanoes with long periods of dormancy?
What crucial role do volcanic earthquakes play in forecasting eruptions, especially for volcanoes with long periods of dormancy?
What is the primary mechanism by which sulfur dioxide (SO₂) released during volcanic eruptions affects global climate, and what is the typical duration of this effect?
What is the primary mechanism by which sulfur dioxide (SO₂) released during volcanic eruptions affects global climate, and what is the typical duration of this effect?
How does magma’s silica (SiO₂) content influence the volcano's eruptive style and what type of volcano is most likely?
How does magma’s silica (SiO₂) content influence the volcano's eruptive style and what type of volcano is most likely?
What is the primary characteristic that differentiates a Plinian eruption from an Ultra-Plinian eruption?
What is the primary characteristic that differentiates a Plinian eruption from an Ultra-Plinian eruption?
How does the addition of volatiles like water ($H_2O$) or carbon dioxide ($CO_2$) contribute to magma formation?
How does the addition of volatiles like water ($H_2O$) or carbon dioxide ($CO_2$) contribute to magma formation?
If a volcanologist observes that the surface of a volcano has risen by 1 meter and sunk by about 1/3 of a meter over a short period, what specific type of volcano might they suspect they are monitoring?
If a volcanologist observes that the surface of a volcano has risen by 1 meter and sunk by about 1/3 of a meter over a short period, what specific type of volcano might they suspect they are monitoring?
Why do people choose to live near volcanoes, despite the known risks, even without the ability to relocate?
Why do people choose to live near volcanoes, despite the known risks, even without the ability to relocate?
What is the Volcanic Explosivity Index (VEI) and how is it used to classify volcanic eruptions?
What is the Volcanic Explosivity Index (VEI) and how is it used to classify volcanic eruptions?
How does the geological history of a volcano contribute to forecasting risks associated with future eruptions?
How does the geological history of a volcano contribute to forecasting risks associated with future eruptions?
In the event of a supervolcanic eruption in the Yellowstone National Park area, what aspects would most likely be affected?
In the event of a supervolcanic eruption in the Yellowstone National Park area, what aspects would most likely be affected?
What factor primarily dictates magma’s density, viscosity, and temperature?
What factor primarily dictates magma’s density, viscosity, and temperature?
Why can it be dangerous to become comfortable with a volcano that hasn't erupted in a long time?
Why can it be dangerous to become comfortable with a volcano that hasn't erupted in a long time?
Viscosity affects a magma’s ability to flow. How does this relate to magmas with different silica contents?
Viscosity affects a magma’s ability to flow. How does this relate to magmas with different silica contents?
Given equivalent volumes of ejecta, under what circumstances would a VEI 4 eruption present a greater hazard than a VEI 3 eruption?
Given equivalent volumes of ejecta, under what circumstances would a VEI 4 eruption present a greater hazard than a VEI 3 eruption?
How does partial melting of rock contribute to the variability observed in magma composition, and what geologic setting would promote differing melts?
How does partial melting of rock contribute to the variability observed in magma composition, and what geologic setting would promote differing melts?
How do lateral blasts differ from typical summit eruptions, and why do they pose a particularly acute threat to nearby populations?
How do lateral blasts differ from typical summit eruptions, and why do they pose a particularly acute threat to nearby populations?
What are the primary volcanic hazards associated with composite volcanoes? Why are lahars common?
What are the primary volcanic hazards associated with composite volcanoes? Why are lahars common?
Which location reflects magma with less silica making less explosive volcanoes?
Which location reflects magma with less silica making less explosive volcanoes?
What is the most important factor dictating magma’s density, viscosity, and temperature?
What is the most important factor dictating magma’s density, viscosity, and temperature?
What is the purpose of scientists measuring small quakes?
What is the purpose of scientists measuring small quakes?
How does magma mixing contribute to the potential for dangerous explosive eruptions, and what is the resulting magma?
How does magma mixing contribute to the potential for dangerous explosive eruptions, and what is the resulting magma?
Why is it important to know the direction of blast, when considering volcanic hazards?
Why is it important to know the direction of blast, when considering volcanic hazards?
What is the typical duration of eruptions?
What is the typical duration of eruptions?
What is the difference in material ejected between VEI 7 and VEI 8 eruptions?
What is the difference in material ejected between VEI 7 and VEI 8 eruptions?
What is the relationship between volcanic activity and climate change?
What is the relationship between volcanic activity and climate change?
How does viscosity affect magma's ability to flow?
How does viscosity affect magma's ability to flow?
What are Jökulhlaups?
What are Jökulhlaups?
Flashcards
What is a Volcano?
What is a Volcano?
An opening in the earth's crust through which lava, volcanic ash, and gases escape.
What is Magma?
What is Magma?
Molten rock underground.
What is Lava?
What is Lava?
Molten rock that has reached the surface.
Active Volcano
Active Volcano
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Dormant Volcano
Dormant Volcano
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Extinct Volcano
Extinct Volcano
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Cinder Cone Volcano
Cinder Cone Volcano
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Shield Volcano
Shield Volcano
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Composite Volcano
Composite Volcano
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Magma Viscosity
Magma Viscosity
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Volcanic Explosivity Index (VEI)
Volcanic Explosivity Index (VEI)
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Pacific Ring of Fire
Pacific Ring of Fire
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Why is magma dangerous?
Why is magma dangerous?
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How magma forms
How magma forms
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Magma's silica content importance
Magma's silica content importance
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Magma Rises
Magma Rises
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Tephra
Tephra
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Ash
Ash
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Volcanic Lahars
Volcanic Lahars
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Pyroclastic Flows
Pyroclastic Flows
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Blast Direction
Blast Direction
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Volcanic Earthquake
Volcanic Earthquake
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Volcanic Tsunami
Volcanic Tsunami
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Volcanic Gases
Volcanic Gases
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Jökulhlaups
Jökulhlaups
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Long Term Prediction
Long Term Prediction
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Measuring Volcano Slope
Measuring Volcano Slope
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Helpful as a recrational
Helpful as a recrational
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Short term Prediction
Short term Prediction
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Cons of climate Change
Cons of climate Change
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Pros of climate change
Pros of climate change
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Fault Line
Fault Line
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Mixing Magmas
Mixing Magmas
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Incorporating Water
Incorporating Water
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Volcano Eruption Prediction
Volcano Eruption Prediction
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Decompression melting
Decompression melting
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Magma Mixing
Magma Mixing
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Fractional Crystallization
Fractional Crystallization
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Magma Squeezed Out
Magma Squeezed Out
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Gentle Eruptions
Gentle Eruptions
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Lava Eruption Styles
Lava Eruption Styles
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Phreatic Explosions
Phreatic Explosions
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Common Volcanic Gases
Common Volcanic Gases
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What is historic or geologic record
What is historic or geologic record
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Useful Aspects of Volcanoes
Useful Aspects of Volcanoes
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Supervolcano Definition
Supervolcano Definition
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Yellowstone National Park
Yellowstone National Park
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Yellowstone Caldera Movement
Yellowstone Caldera Movement
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Measuring Volcanic Gases
Measuring Volcanic Gases
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Eruption Mechanisms
Eruption Mechanisms
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Rock Types
Rock Types
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Intermediate Rock Types
Intermediate Rock Types
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Silica Rich Rock Types
Silica Rich Rock Types
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Predicting Eruptions
Predicting Eruptions
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Monitor Gas Emissions
Monitor Gas Emissions
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Climate Change-Negative Aspect
Climate Change-Negative Aspect
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Magma
Magma
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Volcano Activity
Volcano Activity
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Cinder Cone
Cinder Cone
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Active Volcanic Regions
Active Volcanic Regions
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Volcano location
Volcano location
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Thickening Magma
Thickening Magma
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Volcanic Rock Types
Volcanic Rock Types
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Lightning Storm
Lightning Storm
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Eruption Monitoring
Eruption Monitoring
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Monitor Gases
Monitor Gases
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Volcanic Hazards
Volcanic Hazards
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Level of risk
Level of risk
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Magma Composition
Magma Composition
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Variable Magma Composition
Variable Magma Composition
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Viscosity
Viscosity
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Canadian Volcano Areas
Canadian Volcano Areas
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Nuée Ardente
Nuée Ardente
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Icelandic Jökulhlaups
Icelandic Jökulhlaups
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Landslide during Eruption
Landslide during Eruption
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Volcanic hazard forecasts
Volcanic hazard forecasts
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Side Blast
Side Blast
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Magma Properties
Magma Properties
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Explosive Magma Ingredients
Explosive Magma Ingredients
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Volcano-Induced Floods
Volcano-Induced Floods
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Volcano-Induced Fires
Volcano-Induced Fires
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Volcano-Induced Landslides
Volcano-Induced Landslides
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Volcano-Induced Storms
Volcano-Induced Storms
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Volcanic Risk Assessment
Volcanic Risk Assessment
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Predicting eruption measurements.
Predicting eruption measurements.
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Deadliest Eruption : Tambora
Deadliest Eruption : Tambora
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Bulges on volcano Slope
Bulges on volcano Slope
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Study Notes
- Volcanoes pose dangers, and risk assessment is very important.
Lecture Introduction
- The focus centers on volcanic dangers and eruption predictability.
- Magma thickening obstructs the path to the surface, triggering explosive eruptions.
- Magma thickening arises from mixing with thicker, silica-rich magma or incorporating water.
- The thickening can occur through the existing magma mixing with thicker, more silica-rich magma.
- Explosivity occurs by incorporating water into the magma.
What is a Volcano?
- Volcanoes are openings that release lava, ash, and gases from the Earth's crust.
- Magma, molten rock below the surface, becomes lava upon reaching the surface.
- A magma's behavior is influenced by its gas content and chemical composition, especially silica levels.
- Eruptions are driven by pressure from dissolved gas, similar to a cork popping from a champagne bottle.
Volcano Eruption Likelihood
- Determining eruption violence is critical but poorly defined in volcanology.
- The time factor poses a challenge due to its undefined nature across volcano activity classes.
- Accurate volcano history or activity evidence may be lacking.
Volcano Activity Classes
- Active volcanoes exhibit eruption signs like gas emissions and earthquakes.
- Dormant volcanoes show an absence of unrest signs but retain the potential for future eruptions, dormancy periods lack clear definition.
- Extinct volcanoes have not erupted for extended periods, potentially a million years or more.
Volcano Cones
- Cone shape and size are determined by eruption energy and expelled material
- Cone shape serves as an indicator of eruption danger.
- Cinder cone volcanoes are not very dangerous
- Shield volcanoes are a little dangerous
- Composite (stratovolcanoes) are very dangerous
Cinder Cone Volcanoes
- Cinder cones represent the simplest form, featuring a high-angle cone of ash from a single vent
- Reaching heights of tens to hundreds of meters, but <300 m, they may appear later in an eruption
- Winds influence shape, resulting in either circular or asymmetric cones.
- Usually, they are not very dangerous
- Example: Parícutin, Mexico
Shield Volcanoes
- Shield volcanoes are broad formations with gently sloping sides.
- They typically stand around ~500–700 m high, resulting from eruptions of thin, runny lava (low viscosity).
- Frequent, gentle eruptions constitute minimal danger.
- Example: Hawaiian Islands
Composite Volcanoes
- Composite volcanoes, also known as stratovolcanoes, feature alternating layers of lava and ash.
- Eruptions may manifest as pyroclastic flows instead of lava, leading to explosive and hazardous events.
- They reach heights of up to ~3000 m
- Examples: Mt. Hood, Mt. Shasta, Mt. St. Helens, and Mt. Fuji
Volcano Examples
- Volcanoes exhibit eruption variability worldwide.
- Mount Mazama (Crater Lake) is near enough to leave ash beds in Calgary.
- Developing complacency regarding a volcano due to prolonged inactivity is hazardous.
Crater Lake, Oregon
- The crater was formed by the collapse of Mount Mazama, creating a caldera, while the island represents new lava emerging.
Mount Mazama
- The road in before illustrations (5,600 years ago) is an anachronism.
- After visualizations show the current state of the volcano.
Parícutin, Mexico (1943–1952)
- The observer's comfort during the eruption highlights the peril of underestimating even gentle volcanic activity.
Mount Etna, Italy
- Mount Etna attracts tourists for eruption viewing, but it is one of several hazardous Italian volcanoes.
Mount Etna from Space
- Mount Etna is subject to observation from space.
Cleveland Volcano, Alaska
- Volcanoes with snow cover can produce dangerous mudslides upon eruption.
Lava flow, Hawaii
- Hawaii draws tourists to witness eruptions, especially slow-moving lava flows.
Tambora (Indonesia)
- This Indonesian volcano caused widespread death and starvation due to devastating eruption-related conditions.
Santorini (Thera), Greece
- The explosive eruption triggered a tsunami (tidal wave).
- It potentially served as the basis for the Atlantis mythos.
Volcano Deaths and Injuries
- Volcanic fatalities and injuries arise through both direct and indirect means.
- In modern times, direct deaths from volcanoes average ~540 per year.
- Indirect causes lead to the most extensive harm, affecting larger areas and causing prolonged consequences.
- Indirect factors encompass starvation, drowning, heart attack, and disease.
Deadliest Volcanic Eruptions
- Indirect causes account for most deaths
- Tambora, Indonesia in 1815 caused 92,000 deaths from starvation and had a VEI of 7.
- Krakatau, Indonesia in 1883 had a VEI of 6 and 36,417 deaths from a tsunami
- Mount Pelée, Martinique in 1902 caused 29,025 deaths because of ash flows and had a VEI of 4.
- Ruiz, Columbia in 1985 had a VEI of 3 and 25,000 deaths from mud flows.
- Unzen, Japan in 1792 caused 14,900 deaths because of volcano collapse, and the resulting tsunami, with a VEI of 3.
- Kelut, Indonesia in 1586 had a VEI of 4 and 10,000 deaths, cause unknown.
- Laki, Iceland in 1783 had a VEI of 4 and 9,350 deaths from starvation.
Classes of Eruption
- Effusive (Quiet): Icelandic and Hawaiian.
- Explosive: Strombolian, Vulcanian, Plinian, Caldera-Forming (Ultra-Plinian), and Phreatic (water-containing).
Volcanic Explosivity Index
- Developed in 1982 by two USGS geologists and is used as a hazard guide
- Ranks eruptions by intensity and magnitude using a relative energy scale.
- Greater energy release corresponds to higher potential harm.
- The criteria include eruption plume height, ejecta volume, and eruption duration.
- It features an open-ended scale, where VEI 8 represents the largest eruptions, and values >8 would classify supervolcanoes.
- The scale is logarithmic: each division has 10× more ejecta (except for VEI 0–3).
- Findings from 3,300 historic eruptions:
- 42% persisted for less than a month.
- 33% continued for 1–6 months.
- Only 16 out of 3,300 lasted for >20 years.
- Of 252 explosive eruptions, 42% experienced peak violence on the first day.
Volcanic Explosivity Index (VEI) Classification
- VEI 0: Hawaiian, non-explosive, < 100 m plume height, < 10^4 m³ ejecta volume, daily frequency, Mauna Loa example.
- VEI 1: Hawaiian/Strombolian, gentle, 100–1,000 m plume height, > 10^4 m³ ejecta volume, daily frequency, Stromboli example.
- VEI 2: Strombolian/Vulcanian, explosive, 1–5 km plume height, > 10^6 m³ ejecta volume, weekly frequency, Galeras (1993) example.
- VEI 3: Vulcanian/Pelean, severe, 3–15 km plume height, > 10^7 m³ ejecta volume, yearly frequency, Lassen (1915) example.
- VEI 4: Pelean/Plinian, cataclysmic, 10–25 km plume height, > 0.1 km³ ejecta volume, ≥ 10 years frequency, Soufrière Hills (1995) example.
- VEI 5: Plinian, paroxysmal, > 25 km plume height, > 1 km³ ejecta volume, ≥ 50 years frequency, Mount St. Helens (1980) example.
- VEI 6: Plinian/Ultra-Plinian, colossal, > 25 km plume height, > 10 km³ ejecta volume, ≥ 100 years frequency, Pinatubo (1991) example.
- VEI 7: Plinian/Ultra-Plinian, super-colossal, > 25 km plume height, > 100 km³ ejecta volume, ≥ 1000 years frequency, Tambora (1815) example.
- VEI 8: Ultra-Plinian, mega-colossal, > 25 km plume height, > 1000 km³ ejecta volume, ≥ 10,000 years frequency, Toba (~73,000 BP) example.
Deadliest Volcanic Eruptions
- Tambora, Indonesia (1815)
- VEI: 7
- Deaths: 92,000
- Cause of Deaths: Starvation
- Krakatau, Indonesia (1883)
- VEI: 6
- Deaths: 36,417
- Cause of Deaths: Tsunami
- Mount Pelée, Martinique (1902)
- VEI: 4
- Deaths: 29,025
- Cause of Deaths: Ash flows
- Ruiz, Colombia (1985)
- VEI: 3
- Deaths: 25,000
- Cause of Deaths: Mud flows
- Unzen, Japan (1792)
- VEI: 3
- Deaths: 14,900
- Cause of Deaths: Volcano collapse, tsunami
- Kelut, Indonesia (1586)
- VEI: 4
- Deaths: 10,000
- Cause of Deaths: Unknown / Not recorded
- Laki, Iceland (1783)
- VEI: 4
- Deaths: 9,350
- Cause of Deaths: Starvation
Volcanic Explosivity Index (VEI) Classification
- VEI 0: Hawaiian
- Description: Non-explosive
- Plume Height: < 100 m
- Ejecta Volume: < 10^4 m³
- Typical Frequency: Daily
- Example: Mauna Loa
- VEI 1: Hawaiian / Strombolian
- Description: Gentle
- Plume Height: 100–1,000 m
- Ejecta Volume: > 10^4 m³
- Typical Frequency: Daily
- Example: Stromboli
- VEI 2: Strombolian / Vulcanian
- Description: Explosive
- Plume Height: 1–5 km
- Ejecta Volume: > 10^6 m³
- Typical Frequency: Weekly
- Example: Galeras (1993)
- VEI 3: Vulcanian / Pelean
- Description: Severe
- Plume Height: 3–15 km
- Ejecta Volume: > 10^7 m³
- Typical Frequency: Yearly
- Example: Lassen (1915)
- VEI 4: Pelean / Plinian
- Description: Cataclysmic
- Plume Height: 10–25 km
- Ejecta Volume: > 0.1 km³
- Typical Frequency: ≥ 10 years
- Example: Soufrière Hills (1995)
- VEI 5: Plinian
- Description: Paroxysmal
- Plume Height: > 25 km
- Ejecta Volume: > 1 km³
- Typical Frequency: ≥ 50 years
- Example: Mount St. Helens (1980)
- VEI 6: Plinian / Ultra-Plinian
- Description: Colossal
- Plume Height: > 25 km
- Ejecta Volume: > 10 km³
- Typical Frequency: ≥ 100 years
- Example: Pinatubo (1991)
- VEI 7: Plinian / Ultra-Plinian
- Description: Super-colossal
- Plume Height: > 25 km
- Ejecta Volume: > 100 km³
- Typical Frequency: ≥ 1000 years
- Example: Tambora (1815)
- VEI 8: Ultra-Plinian
- Description: Mega-colossal
- Plume Height: > 25 km
- Ejecta Volume: > 1000 km³
- Typical Frequency: ≥ 10,000 years
- Example: Toba (~73,000 BP)
Areas With Active Volcanoes
- The Pacific Ring of Fire stands out as the largest region of active volcanoes.
- Other active volcanic zones encompass: Hot spots (Hawaii, Long Valley, Yellowstone), mid-ocean ridges (Iceland), continental rift zones (East Africa).
- Over 90% of North America remains insulated from local volcanic activity, though distant major eruptions could still exert effects.
Canadian Volcano Areas
- Within Canada, five areas in BC and the Yukon possess potential volcanic activity:
- Garibaldi Volcanic Belt (southwest BC)
- Wells Gray–Clearwater Volcanic Field (east-central BC)
- Northern Cordilleran Volcanic Province/Stikine Volcanic Belt (northwest BC)
- Anahim Volcanic Belt (central BC)
- Wrangell Volcanic Belt (Alaska and adjacent Yukon Territory)
Why Magma Can Be Dangerous
- Magma viscosity (thickness) governs movement ease.
- Very thick magma can obstruct passages, building pressure and triggering explosions.
- Magma that has high silica (SiO₂) content becomes viscous and explosive.
- High water content (phreatic) also makes magma explosive.
How Magma Forms
- Magma originates from rock melting, or partially melting, with various minerals exhibiting different melting temperatures.
- Most magma is not 100% liquid; a few percent liquid is enough.
- Rocks also melt with the addition of volatiles (H₂O or CO₂), heat transfer, and reduced pressure (decompression).
- A slushy or a frozen margarita are physical analogies.
Magma Composition
- Magma composition controls volcano eruption style: gentle or explosive.
- Significant factors encompass magma density, viscosity, and temperature.
- Silica (SiO₂) content takes precedence as a primary determinant.
- Silica-rich magmas exhibit thickness and viscosity.
- Silica-poor magmas are thin and runny.
Why are Magmas so Variable?
- Variable magmas stem from source rock differences, magma mixing, partial melting, assimilation, and fractional crystallization.
- Melting felsic rock yields felsic magma.
- Mixing silica-rich and silica-poor magma yields intermediate-Si magma.
Magma Movement
- Volcanic rocks depend on magma movement for their formation.
- Magma rises because its greater heat and lower density compared to surroundings, weight of overlying rock literally squeezes out magma
- Viscosity influences magma's flow capacity: Si-rich magma registers higher in viscosity and less flow compared to Si-poor magma.
- Magma movement is similar to squeezing toothpaste or stepping in mud.
Eruption Mechanisms Causing Danger
- Higher silica content in magma corresponds to more explosive volcanoes (continental crust).
- Lower silica content correlates with less explosive volcanoes (oceanic crust).
- These tendencies manifest in distinct rock types across diverse tectonic settings.
Eruption Mechanisms Causing Danger: Rock Types and Tectonic Settings
- Basalt: Lowest % Si, oceanic crust, divergent plate boundaries and hot spots under oceanic crust (e.g., Hawaii).
- Andesite: Intermediate % Si, mixture of oceanic and continental crust, subduction zones: Ring of Fire (Cascadia subduction zone).
- Rhyolite: Highest % Si, continental crust, hot spot under continental crust (e.g., Yellowstone)
Eruption Types
- Explosive eruptions involve felsic magma that has high silica, low temperature, and high volatiles.
- Gentle eruptions feature mafic magma that has low silica, high temperature, and low volatiles.
- Explosive Eruptions form lava domes, ash clouds, and ash flows.
- Gentle Eruptions create fluid lava flows, fire fountains, and lava tubes.
- Anak Krakatau, Sakurajima, Kirishima, Merapi, Stromboli, and Marum are known for being explosive.
- Kīlauea (Hawaii) is known for gentle eruptions.
Volcanic Hazards
- Volcanoes generate varied hazards, depending on the magma's chemical composition/gas content.
- Lava emerges through fire fountains/lava flows (if runny) or steep-sided domes (if viscous); it can destroy property but rarely endangers people.
- Pyroclastic flows describe hot avalanches of rock, ash, and gas descending volcano slopes swiftly, they can be very dangerous.
- Lahars are mixtures of water and volcanic debris that stem from interactions between volcanic materials and water/ice/snow/sediment.
- Lahars are most threatening near volcanoes; large lahars can traverse kilometers along river valleys, endangering populations/infrastructure far beyond volcano slopes.
- A Nevado del Ruiz, Colombia (1985) eruption induced a lahar when it melted a 2.5 km² snow and ice area.
- 28,700 fatalities and 5,000+ ruined structures in Armero (72 km away) resulted from the generated lahar.
- Phreatic (steam-blast) explosions are caused by water interacting with hot rock or magma.
- Jökulhlaups involve significant outburst floods originating from glacial lakes/beneath glaciers, triggered by volcanic eruptions under glaciers that melt ice.
- Landslides and collapses within volcanoes can occur spontaneously or during eruptions, potentially turning into lahars if water is available.
- Even when volcanoes are dormant, landslides pose a regular threat because of steep and unstable conditions.
- During the 1980 Mount St. Helens eruption, around 2.3 km³ of debris slid down at speeds of 240 km/h, depositing a 45 m thick layer over 24 km.
- Mt. Shasta had an eruption 350,000 years ago and resulted in a landslide that was 20× bigger than Mt. St. Helens’.
- Volcanic earthquakes arise from underground movement of magma/fluid, but they often register too subtly for detection without specific tools
- Significant seismic activity tends to precede most eruptions (particularly after long dormant periods), and volcanic earthquakes play a role in forecasting eruptions.
- Tsunamis are giant waves from submarine eruptions or volcanic landslides.
- Common volcanic gases from lava or vents include water vapor, carbon dioxide (CO₂), sulfur dioxide (SO₂), hydrogen, hydrogen sulfide (H₂S), and carbon monoxide (CO).
- Irritation, poisoning, or breathing problems may arise due to some volcanic gases, while sulfur dioxide can trigger acid rain, and volcanic gases may affect climate due to CO₂ and H₂O emissions.
- Tephra denotes rock fragments ejected from volcanoes; ash is tephra < 2 mm; larger fragments are lapilli, bombs, or blocks.
- Blocks and bombs tend to fall within a few kilometers, and ash may reach high into the atmosphere and travel long distances.
- Ash accumulation may disrupt vehicle/plane engines, and even centimeters can cause roof collapses.
- Blast direction matters on a small scale.
- While most volcanoes erupt at the summit, eruptions can occur without warning through the side of a volcano; for example, the 1980 Mt. St. Helens eruption.
Ashfall Fossil Beds State Historical Park, Nebraska
- Animals fell victim to ash fall from 10 million years ago
- Lung failure led to the deaths (not burial), resulting in the park's formation.
- Mt. St. Helens (1980): Ash flows annihilated 60 people, thousands of animals/fish, and timber acres.
- Mt. Vesuvius (AD 79): Nuée ardente (pyroclastic flow) killed ~20,000 people in Pompeii.
- Gases and ash at Pompeii, Italy caused quick deaths for people and animals.
Links Between Volcanoes and Other Hazards
- Volcanoes are linked to other hazards like fire, earthquakes, lightning storms, landslides, tsunamis, floods, and climate change.
Fire
- Structures, crops, and plants are vulnerable to ignition from lava flows, pyroclastic flows, and superheated volcanic bombs.
Earthquakes
- Earthquakes often occur before or during eruptions; most pose limited damage.
Tsunamis
- Volcano-related earthquakes or landslides can trigger tsunamis.
- Damage tends to concentrate around areas close to the volcano.
Landslides
- Landslides are the most frequent secondary effect.
- Caldera formation can trigger landslides.
- Lahars and melting snow/ice may also initiate landslides.
Lightning Storms
- Intense lightning storms result when Ejecta is combined with expelled water.
- These storms present a fire hazard.
Floods
- Lahars can obstruct river valleys, resulting in floods.
- Melting snow and ice from volcanic heat can cause downhill floods.
- Jökulhlaups may also occur when volcanoes melt ice that dams glacial lakes, particularly common in Iceland.
Climate Change
- The Volcanic effects on climate can vary significantly.
- Ash blocks sunlight in the upper atmosphere, which lowers temperature (glacial episodes in extreme cases).
- Sulfur dioxide yields aerosols in the upper atmosphere, reflecting sunlight and cooling the planet.
- Carbon dioxide and water vapor act as greenhouse gases, causing warming.
Perception of Volcanic Hazards
- Risk management depends on understanding perception; information remains limited regarding this.
- People reside near volcanoes due to factors like birthplaces, fertile land, optimism, a lack of choice, and unawareness of any risk.
Minimizing Hazards
- Forecasts state the time and probability of an eruption but are less definite than a prediction.
- Lowering risk through forecasting stands as a key strategy.
- These forecasts rely on analyzing seismic activity, volcano conditions, land surface changes, volcanic gas emissions, and the geologic history of the volcano.
- Issuing a Volcanic Alert or Warning, using ground-based observations and aerial reconnaissance, isn't always effective in promoting timely evacuations or precise timing.
Predictions are based on:
- Detecting small increases in the number and intensity of small quakes before possible eruption.
- Volcano bulges can be measured using tiltmeters and are caused by magma accumulation.
- Monitoring the change in volcanic outflow of gases (particularly sulfur dioxide and carbon dioxide) to see if magma is rising towards the vent.
- Changes in Gas concentrations may reflect the movement of magma upward.
- Satellites detect changes in surface temperature.
Predicting Eruptions
- Best predictions result from Combining different methods.
Long-Term Prediction
- Assess frequency plus style of past volcano eruptions.
- Ascertain probabilities, style, and locations for eruptions in individual volcanoes.
- Establish the level of risk based on the historic/geologic record.
- Determine typical routes for lahars, nuée ardentes (pyroclastic flows), and lava flows to strategically avoid infrastructure development in these zones.
Short-Term Prediction
- Identify patterns preceding previous eruptions.
- Monitor gas emissions.
- Key gases during monitoring are sulfur dioxide (SO₂) and carbon dioxide (CO₂).
- Changes in gas concentrations may reflect the movement of magma upward.
Useful Aspects of Volcanoes
- Geothermal power can be harnessed (e.g., in California, Hawaii, Nevada, Italy, New Zealand).
- Recreation is possible in the hot springs (e.g., Radium, Banff, Jasper in Canada).
- New land creation (e.g., the islands of Iceland and Hawaii), and Volcanic soils are very fertile.
Supervolcanoes
- Supervolcanoes have eruptions that eject ~1000 km³ or more of pyroclastic material (> VEI 8) with massive eruptions occurring about every 50,000 years.
Yellowstone National Park
- Yellowstone features hot springs and geysers and it is the world’s most famous supervolcano.
- Active caldera moves due to magma movement and shows signs of surface changes.
- The magma chamber lies 5–13 km beneath the surface.
- The caldera measures around ~80 km long and 50 km wide.
- Movement causes thousands of small earthquakes.
How Calderas Form
- Hot spot in the mantle has moved several hundred kilometers over the past 12.5 million years causing the caldera and magma chamber.
- Drift of the North American plate over the hot spot caused this movement.
- Inactive calderas represent the hot spot’s path.
- The Lava Creek eruption caused the present caldera 640,000 years ago, ejecting ~1,000 km³ of pyroclastic debris.
- The Huckleberry Ridge eruption, having ejected ~2,500 km³ of pyroclastic debris, occurred ~2 million years ago.
- A smaller eruption releasing ~280 km³ of debris occurred 1.3 million years ago.
Yellowstone Eruptions
- Super-eruptions have spread ash over thousands of square kilometers of the US.
- Heightened monitoring of Yellowstone in recent years has led to media concern about an impending eruption.
- Government officials and geologists report no clear signs of high risk at present. A super-eruption might cause a “Dark Age” for North America and the world.
- Yellowstone may be considered “overdue” but there are caveats:
- Worldwide supervolcano eruptions occur roughly every 50,000 years, but Yellowstone’s super-eruptions are much less frequent.
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