Earth's Internal Structure Quiz

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Questions and Answers

What layer of the Earth is located directly above the outer core?

Lower Mantle (correct)

Inner Core

Crust

Asthenosphere

Which element primarily composes the inner core?

Solid Nickel (correct)

Aluminum

Magnesium

Liquid Iron

What is the temperature of the outer core?

3,000 degrees Celsius

1,000 degrees Celsius

4,000 degrees Celsius

2,000 degrees Celsius (correct)

Which term describes the boundary between the lower mantle and the outer core?

Gutenberg Discontinuity Signup and view all the answers

What is the primary function of a seismometer?

To record seismic waves Signup and view all the answers

Where do seismic waves originate?

From the focus of an earthquake Signup and view all the answers

What generates the Earth's magnetic field?

The outer core Signup and view all the answers

How thick is the outer core?

2,300 km Signup and view all the answers

What is the approximate thickness range of the continental crust?

35 to 40 km Signup and view all the answers

Which layer of the Earth composes the majority of its mass?

Mantle Signup and view all the answers

What is the Moho or Mohorovicic Discontinuity?

Boundary between the Earth's crust and the mantle Signup and view all the answers

Which of the following statements is true regarding the Earth’s crust?

It is solid and constitutes 1% of Earth's volume Signup and view all the answers

What type of seismic wave is known for moving the ground both up and down and side-to-side?

Rayleigh wave Signup and view all the answers

What is the approximate depth of the Kola Superdeep Borehole?

12 km Signup and view all the answers

Which seismic wave can travel through both solid and liquid layers of the Earth?

P-wave Signup and view all the answers

Among the two types of surface waves, which one is considered to be the most destructive?

Love wave Signup and view all the answers

Which type of crust is primarily made up of basalt?

Oceanic crust Signup and view all the answers

What is the approximate age of the Earth?

4.54 billion years Signup and view all the answers

What is the key difference between P-waves and S-waves?

P-waves can travel through both solids and liquids, while S-waves can only travel through solids. Signup and view all the answers

Which statement about the mantle is correct?

It comprises 84% of the volume of the Earth Signup and view all the answers

Which method is commonly used to locate the epicenter of an earthquake?

Triangulation method Signup and view all the answers

If the S-wave can only pass through solids, which layer of the Earth can it penetrate?

Mantle Signup and view all the answers

What factor is critical in determining the distance of the epicenter from a seismograph station?

Time difference between P-wave and S-wave arrivals Signup and view all the answers

At what approximate speed does a P-wave travel?

6 km per second Signup and view all the answers

Study Notes

Earth's Internal Structure

Earth is 4.54 billion years old.
Earth's internal structure is comprised of four layers:
- Crust: The thinnest layer, only 1% of Earth's volume.
  - Solid state.
  - 5-100 km thick.
  - Comprised of elements like Silicon, Oxygen, Aluminum, Iron, Calcium, Sodium, Potassium, and Magnesium.
  - Two types:
    - Continental Crust: 35-40 km thick, mostly composed of granite.
    - Oceanic Crust: 5-10 km thick, mostly composed of basalt.
- Mantle: The thickest layer, comprising 84% of Earth's volume and 70% of its mass.
  - 2900 km thick.
  - Composed of elements like iron, magnesium, silicon, oxygen, calcium, and aluminum.
  - Two sub-layers:
    - Upper Mantle: Contains the lithosphere (crust and upper mantle) and asthenosphere (where convection currents occur).
    - Lower Mantle: Extends from 660 km to 2,700 km beneath Earth's surface, hotter and denser than the upper mantle.
- Outer Core:
  - 2,300 km thick.
  - Temperature of 2,000 degrees Celsius.
  - Composed primarily of liquid Nickel and Iron.
  - Generates Earth's magnetic field.
- Inner Core:
  - 1,220 km in diameter.
  - Temperature of 5,000 degrees Celsius.
  - Composed of solid Nickel and Iron.

Boundaries Between Layers

Mohorovicic Discontinuity: The boundary between the Earth's crust and the mantle.
Gutenberg Discontinuity: The boundary between the lower mantle and the outer core.
Lehmann Discontinuity: The boundary between the outer core and inner core.

Seismic Waves

Seismic waves are waves of energy that travel through Earth's layers, generated at the focus of an earthquake.
Types of Seismic Waves:
- Surface Waves:
  - Travel along Earth's surface.
  - Two types:
    - Rayleigh waves: Move the ground up and down and side to side.
    - Love waves: Move solely side to side horizontally, considered the most destructive.
- Body Waves:
  - Travel through Earth's interior.
  - Two types:
    - P-Wave (Primary Wave): Compressional/longitudinal wave. Travels faster than S-wave.
      - Can travel through solid and liquid.
      - Travels at a rate of 6 km per second.
    - S-Wave (Secondary Wave): Transverse/shear wave. Travels slower than P-waves.
      - Can only travel through solids.
      - Travels at a rate of 4 km per second.

Locating Epicenter

Triangulation Method: Used to locate an earthquake's epicenter.
- Uses the difference in arrival times of P and S waves from different seismograph stations.
- Steps:
  1. Determine the time difference between the arrival of P-waves and S-waves at different stations.
  2. Use a formula (d = Td) to calculate the distance from each station to the epicenter.
  3. Convert the distances to centimeters.
  4. Plot the distances on a map to pinpoint the epicenter.

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Description

Test your knowledge on the Earth's internal structure, including its layers such as the crust and mantle. Explore the composition and characteristics of each layer, including the differences between continental and oceanic crust. This quiz covers essential concepts related to the Earth's geology.