Question

Which discontinuity separates the Earth’s crust from the underlying mantle?

• A. Gutenberg Discontinuity
• B. Conrad Discontinuity
• C. Moho Discontinuity
• D. Repetti Discontinuity

Answer 1

Answer:

C. Moho Discontinuity

• Correct Answer: Option C) Moho Discontinuity

• The Moho discontinuity, commonly known as the Moho discontinuity, is the boundary that separates the Earth's crust from the underlying mantle.

• The Moho discontinuity is characterized by a sharp increase in seismic wave velocities, which occurs due to the change in rock composition and density between the crust and mantle. The crust consists primarily of lighter rocks like granite and basalt, while the mantle is composed of denser rocks such as peridotite.

• The depth of the Moho varies depending on location:

• Under oceanic crust: approximately 5-10 kilometers deep

• Under continental crust: approximately 20-70 kilometers deep, with thicker crust under mountain ranges

• The other options mentioned are different discontinuities within the Earth:

• Gutenberg Discontinuity: separates the mantle from the outer core

• Conrad Discontinuity: separates the upper and lower continental crust

• Repetti Discontinuity: separates the outer core from the inner core

• Understanding these discontinuities is crucial for studying Earth's internal structure and seismic wave propagation patterns.