Podcast
Questions and Answers
What type of meteorites are thought to represent the bulk composition of Earth?
What type of meteorites are thought to represent the bulk composition of Earth?
Oceanic crust is thicker and less dense than continental crust.
Oceanic crust is thicker and less dense than continental crust.
False
How old are certain meteorites that represent the bulk composition of Earth?
How old are certain meteorites that represent the bulk composition of Earth?
Approximately 4.5 billion years old
The outer core of the Earth is ________.
The outer core of the Earth is ________.
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Match the following crust types with their characteristics:
Match the following crust types with their characteristics:
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Which layer of the Earth is known to be solid but behaves like a plastic under pressure?
Which layer of the Earth is known to be solid but behaves like a plastic under pressure?
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Geomagnetic storms can occur as a result of coronal mass ejections interacting with Earth's magnetosphere.
Geomagnetic storms can occur as a result of coronal mass ejections interacting with Earth's magnetosphere.
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Normal faults occur due to ________ forces.
Normal faults occur due to ________ forces.
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What type of fault involves lateral motion where blocks slide past each other?
What type of fault involves lateral motion where blocks slide past each other?
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S-waves can travel through both solids and liquids.
S-waves can travel through both solids and liquids.
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What is the primary difference between magnitude and intensity in seismic terms?
What is the primary difference between magnitude and intensity in seismic terms?
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The __________ zone is capable of generating megathrust earthquakes in Victoria, BC.
The __________ zone is capable of generating megathrust earthquakes in Victoria, BC.
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Match the following seismic wave types with their characteristics:
Match the following seismic wave types with their characteristics:
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Which of the following factors can affect the peak intensity of an earthquake?
Which of the following factors can affect the peak intensity of an earthquake?
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Urbanization and population growth in seismic areas increase seismic risk.
Urbanization and population growth in seismic areas increase seismic risk.
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What phenomenon occurs when a building's natural frequency matches the frequency of seismic waves?
What phenomenon occurs when a building's natural frequency matches the frequency of seismic waves?
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Which condition contributed to the Montecito mudflows in 2018?
Which condition contributed to the Montecito mudflows in 2018?
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The head scarp is located at the base of a landslide.
The head scarp is located at the base of a landslide.
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What is the purpose of basal failure surface in a landslide?
What is the purpose of basal failure surface in a landslide?
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The __________ are cracks that develop perpendicular to the slope's movement, indicating tension within the sliding mass.
The __________ are cracks that develop perpendicular to the slope's movement, indicating tension within the sliding mass.
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Match the landslide features to their descriptions:
Match the landslide features to their descriptions:
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Which type of magma has the highest viscosity?
Which type of magma has the highest viscosity?
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Lower viscosity magma results in explosive eruptions.
Lower viscosity magma results in explosive eruptions.
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What is a pyroclastic flow?
What is a pyroclastic flow?
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Mount Pelee's eruption in 1902 was primarily caused by __________ collapse.
Mount Pelee's eruption in 1902 was primarily caused by __________ collapse.
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Which volcanic setting is associated with the least explosive eruptions?
Which volcanic setting is associated with the least explosive eruptions?
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Match the following volcanoes with their characteristics:
Match the following volcanoes with their characteristics:
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Water decreases the likelihood of landslides by reducing soil weight.
Water decreases the likelihood of landslides by reducing soil weight.
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The majority of volcanism occurs at __________, responsible for about 80%.
The majority of volcanism occurs at __________, responsible for about 80%.
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What is the primary factor that contributes to the formation of tornadoes in Tornado Alley?
What is the primary factor that contributes to the formation of tornadoes in Tornado Alley?
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Tornadoes are only formed during the summer months in North America.
Tornadoes are only formed during the summer months in North America.
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Name one technique used for wildfire suppression.
Name one technique used for wildfire suppression.
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Tropical cyclones form when sustained winds exceed _____ km/h.
Tropical cyclones form when sustained winds exceed _____ km/h.
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Match the following wildfire factors to their descriptions:
Match the following wildfire factors to their descriptions:
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What causes creep in geological terms?
What causes creep in geological terms?
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The 2018 Montecito Mud Flow was caused by burned vegetation and minimal rainfall.
The 2018 Montecito Mud Flow was caused by burned vegetation and minimal rainfall.
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What is a lahar?
What is a lahar?
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A _____ is a fast-moving disintegration of rock.
A _____ is a fast-moving disintegration of rock.
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Which type of flow is characterized by wet mud?
Which type of flow is characterized by wet mud?
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Match the type of landslide with its description:
Match the type of landslide with its description:
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Which event caused the death of 43 people in Washington?
Which event caused the death of 43 people in Washington?
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Wind waves have more energy than tsunami waves even if both are the same height.
Wind waves have more energy than tsunami waves even if both are the same height.
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Study Notes
Earth's Structure and Tectonics
- Certain meteorites, like chondrites, are similar in composition to Earth's bulk, representing early solar system material (approximately 4.5 billion years old).
- Earth's structure includes the lithosphere (rigid), asthenosphere (plastic), mesosphere (solid under pressure), outer core (liquid), and inner core (solid).
- Compositional layers are the crust (silicates), mantle (silicate minerals with Mg and Fe), and core (iron-nickel alloy).
- Oceanic crust is basaltic, rich in iron and magnesium, denser and thinner, while continental crust is granitic, silica-rich, less dense and thicker.
- Coronal Mass Ejections (CMEs) are large plasma and magnetic field ejections from the sun, which interact with Earth's magnetosphere, causing geomagnetic storms, and impacting satellite, GPS, and power grid functions.
- Evidence for continental drift and plate tectonics includes fossil distribution patterns, symmetrical magnetic striping on the seafloor, and sonar discoveries like mid-ocean ridges, deep ocean trenches and fracture zones.
Earthquakes
- Fault types include normal faults (extension, hanging wall moves down), reverse/thrust faults (compression, hanging wall moves up), and strike-slip faults (lateral motion).
- Seismic waves include P-waves (fastest, compressive, travel through solids and liquids), S-waves (slower, shear, travel through solids only), and surface waves (slowest, most destructive, travel along the surface).
- Earthquake magnitude measures the energy released at the source, while intensity describes the shaking effects on people and structures, with shallow earthquakes more intense near the epicenter and buildings constructed with poor quality or in poor geology being more affected by ground shaking.
- Factors influencing earthquake intensity include proximity to the epicenter, depth of focus, and local geology.
- Building heights and natural frequencies can cause resonance during an earthquake, with mid-rise buildings more susceptible to those effects.
- Interplate earthquakes occur on reactive ancient faults or rift zones within plates.
- Seismic risk in Victoria, BC, is increased by population growth, and proactive mitigation measures like well-constructed buildings and early warning systems can help reduce risk from earthquakes.
Volcanoes
- Magma viscosity is crucial to eruption style: higher viscosity magmas (like rhyolitic) trap gas, leading to explosive eruptions, while lower viscosity magmas (like basaltic) allow gas to escape, resulting in effusive eruptions.
- Pyroclastic flows are fast-moving currents of hot gas, ash, and volcanic material, formed by eruption column collapse or dome collapse, and can cause significant destruction as happened during the Mount St. Helens 1980 eruption.
- Tectonic settings matter for volcanic activity. Ocean hotspots, mid-ocean ridges, and volcanic arcs have different volcanic types (shield, stratovolcanoes).
- The 2010 Eyjafjallajökull eruption in Iceland had impact on air travel disruption across Europe due to volcanic ash clouds.
Landslides
- Water increases landslide likelihood by increasing the mass and reducing friction.
- Key landslide features include head scarps (top of the slide), transverse cracks (perpendicular to slope), toes (accumulation at the base), and basal failure surfaces.
- The 2018 Montecito mudflows, triggered by intense rainfall after wildfires, illustrate how pre-existing conditions increase landslide risk.
- Landslides can be categorized into types based movement mechanisms: falls, slides (rotational, transitional), flows (earth, debris, mud).
- Factors like slope angle, added mass, shaking, and friction reduction affect landslide susceptibility.
Tsunamis
- Tsunamis are large waves generated by earthquakes, volcanic eruptions, landslides. They are different from wind waves because Tsunamis have much longer wavelengths and high energy that travels great distances.
- Megathrust earthquakes are more likely to create ocean-wide tsunamis as they displace large sections of the seafloor.
- Factors influencing tsunami impact include run-up height, bathymetry or shape of the coast, and the size of the area affected, with larger areas affected by larger tsunamis causing more damage.
Wind and Climate Hazards
- Wind hazards vary geographically, considering the factors, such as, air density, pressure, and temperature.
- Tropical cyclones (hurricanes, typhoons) are strong storms with sustained winds exceeding a certain speed.
- Tornadoes are violent, short-lived storms, characterized by rotating updrafts, which require particular atmospheric conditions.
- Wildfires are significant hazards impacted by dry conditions, high winds, and warm temperatures.
- Understanding and predicting these hazards are crucial for risk mitigation and planning, including warning systems and preparedness strategies.
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Description
Test your knowledge on meteorites, Earth's layers, and seismic waves with this engaging quiz. Explore the characteristics of different crust types and faults, as well as concepts related to geomagnetic storms and earthquakes. Prepare to dive into the fundamental principles of geology.
