Multiple choice

Consider the following statements in relations to Earth's topmost layer:

  1. Transverse earthquake waves moves at a speed of 3.5 km/second in that layer.
  2. The specific gravity is 2.7.
  3. It is shallowest under Continents and deepest under Oceans.
  4. Abundance of magnesium. Which of the above statements are correct

  1. 1 and 2

  2. 2 and 3

  3. 3 and 4

  4. 1, 2 and 4
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Statements 1 and 2 are correct about the Earth's crust (topmost layer). S waves travel at approximately 3.5 km/s in the crust, and the specific gravity is about 2.7 (crust is less dense than mantle). Statement 3 is incorrect - the crust is thickest (deepest) under continents (30-50 km) and thinnest under oceans (5-10 km). Statement 4 is incorrect - the crust is abundant in silica and aluminum (sial), not magnesium (which dominates the mantle).

Keep practicing — related questions