Explain how earthquake waves are used as an indirect source for understanding the structure of the interior of the earth. 10 marks

Mentor’s comment-

• In the introductione briefly write about the earthquale waves.
• In the body explain that yhe knowledge about interior of the earth is obtained through direct sources and indirect sources.Then explain in detail how earthquakes form key sources in
  understanding the Earth’s interiors.
• Conclude with importance and relevance.