Earthquakes, Volcanoes, and Plate Tectonics. Earth’s plates move around, collide, move apart, or slide past each other. The movement of these plates can.

Earthquakes, Volcanoes, and Plate Tectonics

Earthquakes, Volcanoes, and Plate Tectonics

• Earth’s plates move around, collide, move apart, or slide past each other.

• The movement of these plates can cause vibrations known as earthquakes, and can create conditions that cause volcanoes.

Earthquakes, Volcanoes, and Plate Tectonics

Question: Is there a correlation between plate tectonics and volcano formation?

Earthquakes, Volcanoes, and Plate Tectonics

Divergent Plate Boundaries

• Tectonic plates move apart.–As plates separate, long cracks called rifts form between them.

–Rifts contain fractures that allow magma to flow to the surface.

Divergent Plate Boundaries

• Rift zones account for the most lava flow onto Earth’s surface.

Divergent Plate Boundaries

• Fissure eruptions often occur along rift zones. Divergent Boundary demo

Convergent Plate Boundaries

• Volcanoes often form along convergent plate boundaries.

• Two plates move toward each other. If the plates are of equal density, they push up against each other, forming a mountain chain. If they are of unequal density, one plate sinks beneath the other in a subduction zone. Convergent Boundary demo.

• Divergent, Convergent, Transform Boundaries video 6:08

Convergent Plate Boundaries

Hot Spots• Hot Spots: Large bodies of

magma are forced upward through Earth’s mantle and crust.

• Hot Spots video 3:00

Earthquakes, Volcanoes, and Plate Tectonics

• Review: Name the three methods that volcanoes can form.

1. Along rift lines.

2. Subduction zones

3. Hot spots

Moving Plates Cause Earthquakes

• Earthquakes often occur where tectonic plates come together.

Moving Plates Cause Earthquakes

• Question: Why do earthquakes occur in the shown locations?

Moving Plates Cause Earthquakes

• Earthquake locations have a close relationship with tectonic plate boundaries.

• Movement of these plates produces the forces that generate the energy to cause earthquakes.

Moving Plates Cause Earthquakes

• 80% of all earthquakes occur in the Pacific Ring of Fire.

Moving Plates Cause Earthquakes

• Researchers learn much about Earth’s interior and plate tectonics by studying seismic waves.

• The way seismic waves pass through a material is determined by its properties.

• How Do Scientists Know What’s Inside the Earth? 1:22. Brain Pop; Plate Tectonics