Why do glaciers move?

Answer: Gravity and ice deformation

Gravity and ice deformation ✓ — Correct! Glaciers move through two mechanisms: internal deformation and basal sliding. Under immense pressure from their own weight, ice crystals deform and flow like a very viscous fluid - gravity pulls them downhill. At the base, friction melts some ice, creating a thin water layer that acts as lubricant. Glaciers can move millimeters to meters per day! They've carved valleys and shaped landscapes over thousands of years.

Ocean currents pull them — Wrong. Ocean currents don't pull glaciers. Valley glaciers move downhill due to gravity, while ice sheets spread outward from their centers. When glaciers reach the ocean, they can form icebergs that drift with currents, but the glacier itself moves due to gravity and ice physics.

Earthquakes shake them loose — Wrong. Earthquakes don't cause glacier movement. Glaciers move continuously and slowly due to gravity and ice deformation under pressure. While earthquakes might trigger ice avalanches on steep glacier faces, they don't cause the basic slow flow of glaciers.