Volcanoes, Earthquakes, and Mountain Ranges

Introduction

• Welcome to the lesson on volcanoes, earthquakes, and mountain ranges.
• The goal is to describe and relate the distribution of active volcanoes, earthquake epicenters, and major mountain belts to plate tectonics.

Earth's Structure

• Earth is composed of four layers:
  • Crust
  • Mantle
  • Outer Core
  • Inner Core
• Two main types of Earth's crust:
  • Continental Crust: Thick (30-50 km), forms continents.
  • Oceanic Crust: Thin (5-10 km), denser, forms ocean floors.

Lithosphere and Tectonic Plates

• Lithosphere: Outermost layer including the crust and upper mantle.
• Lithosphere broken into tectonic plates, akin to a cracked eggshell.
• Tectonic plates are in constant, slow motion:
  • Move apart
  • Push together
  • Slide past each other
• Plate movement caused by mantle heat currents.

Geological Features and Events

• Mountains: Form when plates collide.
• Volcanoes: Created through subduction, when one plate dives under another.
• Earthquakes: Result from plates sliding past or colliding.

Plate Tectonics

• Drives the movement of Earth's plates, shaping Earth's surface and causing geological events.
• Ring of Fire: A major area in the Pacific with frequent earthquakes and volcanic eruptions.

Philippines and Tectonic Plates

• Philippines located in a tectonically active region (Ring of Fire).
• Influenced by several tectonic plates:
  • Philippine Sea Plate: East, causes earthquakes and volcanoes.
  • Eurasian Plate: Northwest, interacts with Philippine Sea Plate.
  • Pacific Plate: Further east, influences seismic activity.
  • Sunda Plate: Southwest, affects southern Philippines.

Conclusion

• Summary of key ideas:
  • Lithosphere consists of crust and upper mantle, divided into plates.
  • Two crust types: continental (thicker) and oceanic (denser).
  • Plate tectonics theory explains Earth's crust movement, causing earthquakes, volcanoes, and mountains.
  • Plate interactions are concentrated near edges of continents, leading to seismic and volcanic activity.
• Upcoming topic: Plate boundaries.