Earthguide Online Classroom

Earth's crust

Isopach map showing thickness of the Earth's crust in km.

Map source: Map of Crustal Thickness

Map documented in:
W.D. Mooney, G. Laske and G. Masters, 1998. CRUST 5.1: A global crustal model at 57°x5°. J. Geophys. Res., 103, 727-747.

Questions for thought

  1. How does an isopach map differ from a contour map?
  2. Is the thickness of the crust related to land or ocean?
  3. Where is the crust thicker - under land or oceans?
  4. How thick is the crust 1) under land and 2) under oceans in units of kilometers and miles?
  5. How do scientists know the depth to the bottom of the crust?
  6. What is the Moho or "Mohorovic discontinuity"?

Related resources

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