Page 146 - Science Course 2 (Book 2)
P. 146
Mo11-L3b: Why Plate Tectonics Move?
Notice the relationship between earthquake epicenters, volcanoes, and plate boundaries.
Key Concept Plate motion: basal drag, ridge push, and slab pull.
Why Plate Tectonics Move?
How are earthquakes and volcanoes related to the
theory of plate tectonics?
Key Concept
Why Plate Tectonics Move?
What causes convection?
Plate Motion
Earth’s plates move because the asthenosphere
moves underneath the lithosphere.
Convection is the circulation of material caused by
differences in density.
Hot mantle material rises upward and comes in con-
tact with Earth’s crust.
Basal drag refers to how convection currents in the
asthenosphere circulate and drag the lithosphere
like a conveyor belt.
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