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Questions and Answers
What is the average thickness of Earth's continental crust?
What is the average thickness of Earth's continental crust?
Where is the crust of Earth's continents thickest?
Where is the crust of Earth's continents thickest?
Why haven't scientists collected samples from Earth’s core?
Why haven't scientists collected samples from Earth’s core?
What is the name of the deepest borehole on Earth located in northwestern Russia?
What is the name of the deepest borehole on Earth located in northwestern Russia?
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Which compositional layer of Earth is the outermost?
Which compositional layer of Earth is the outermost?
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What causes seismic waves?
What causes seismic waves?
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What is the reason for the mantle being denser than the crust?
What is the reason for the mantle being denser than the crust?
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What evidence do scientists use to infer the properties of the asthenosphere?
What evidence do scientists use to infer the properties of the asthenosphere?
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What does the graph showing the velocity of P- and S-waves with depth in Earth’s mantle reveal?
What does the graph showing the velocity of P- and S-waves with depth in Earth’s mantle reveal?
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What is the reason for the occurrence of the aurora borealis near the poles?
What is the reason for the occurrence of the aurora borealis near the poles?
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What drives the flow of the solid rock of the mantle according to the text?
What drives the flow of the solid rock of the mantle according to the text?
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What are scientists able to infer about the asthenosphere based on seismic data?
What are scientists able to infer about the asthenosphere based on seismic data?
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Why do many stony meteorites appear to be similar to rock on Earth’s crust?
Why do many stony meteorites appear to be similar to rock on Earth’s crust?
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What do seismic waves reveal about the internal layers of Earth?
What do seismic waves reveal about the internal layers of Earth?
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What drives convection in the mantle according to the text?
What drives convection in the mantle according to the text?
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What do gradual changes in seismic waves with depth indicate?
What do gradual changes in seismic waves with depth indicate?
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Study Notes
Earth's Crust and Composition
- Average thickness of Earth's continental crust is approximately 30-50 kilometers.
- The continental crust is thickest in mountain ranges, such as the Himalayas.
Earth's Core and Boreholes
- Scientists have not collected samples from Earth’s core due to extreme temperatures and pressures.
- The deepest borehole on Earth, the Kola Superdeep Borehole, is located in northwestern Russia.
Earth's Layers
- The outermost compositional layer of Earth is the crust.
- The mantle is denser than the crust due to increased pressure and temperature as depth increases.
Seismic Activity and Evidence
- Seismic waves are caused by the sudden release of energy in the Earth's interior, often due to tectonic movements.
- Properties of the asthenosphere are inferred from seismic data, which provides information about wave speeds and behavior as they travel through different layers.
Wave Velocity and Insights
- A graph showing the velocity of P- and S-waves with depth in Earth’s mantle reveals changes in material properties and states (solid/liquid).
- Gradual changes in seismic wave velocity with depth indicate transitions between layers with different densities and states of matter.
Additional Geophysical Phenomena
- The aurora borealis occurs near the poles due to interactions between solar wind particles and Earth’s magnetic field.
- Flow of solid rock in the mantle is driven by heat from the Earth's inner layers, creating convection currents.
Meteorites and Internal Layers
- Many stony meteorites resemble rocks found in Earth's crust due to similar mineral compositions.
- Seismic waves help reveal the internal structure of Earth, showing variations in layers based on wave behavior and velocity changes.
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Description
Test your knowledge on Earth's dynamic interior, crust thickness, and evidence of structure and composition in this quiz based on Unit 6 Lesson 1 of HMH Science Dimensions Earth and Space Science.
