How Are Earthquakes Related to Plate Tectonics?
ES1001  Earthquake Depths

The focus of an earthquake is the actual point underground where rocks break. The depth of the focus can be categorized as shallow (up to 70 km below the surface), intermediate (70 to 300 km), or deep (greater than 300 km).

  !   Click the buttons below to see the global distribution of shallow, intermediate, and deep earthquakes.

Jennifer Loomis, TERC

3. Which depth range has the most earthquakes? Which depth range has the fewest earthquakes?

4. At what type of plate boundary do you find most deep-focus earthquakes?

5. Explain why deep-focus earthquakes occur at this type of plate boundary but not at others.

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