Question

Which of the following are indirect sources of information about the Earth’s interior?

1. Deep Ocean Drilling Project

2. Gravity measurements

3. Seismic activity

• A. 1 & 2
• B. 2 & 3
• C. 1 & 3
• D. All are correct

Answer 1

Answer:

B. 2 & 3

• Correct Answer: Option B) 2 & 3

• The study of Earth's interior structure relies on various methods since direct observation is impossible due to extreme depths, temperatures, and pressures. These methods are classified as direct and indirect sources of information.

• Direct Sources:

• Deep Ocean Drilling Project and other drilling operations that can physically sample materials from the Earth's crust

• Mining operations that provide access to subsurface materials

• Volcanic eruptions that bring deep materials to the surface

• Indirect Sources:

• Gravity measurements: Variations in gravitational field strength indicate differences in density of subsurface materials, helping scientists understand the distribution of mass within Earth

• Seismic activity: Earthquake waves (P-waves, S-waves, surface waves) travel through Earth's interior at different speeds depending on the material they pass through, providing crucial information about internal structure and composition

• Magnetic field studies

• Heat flow measurements

• Laboratory experiments on rock behavior under high pressure and temperature