Overview
This lesson explains what drives tectonic plate movement, focusing on convection currents, ridge push, slab pull, and real-world effects, especially in the Philippines.
Convection Currents and Mantle Movement
- Earth's core is extremely hot and its escaping heat powers mantle movement and plate tectonics.
- Convection currents form as hot mantle rises, cools, sinks, and cycles, dragging tectonic plates above.
- Convection currents work like boiling water, with hot material rising and cool material sinking.
Driving Forces of Plate Movement
- Ridge Push: Gravity pushes older crust away from mid-ocean ridges as new magma rises and solidifies.
- Slab Pull: The denser oceanic plate sinks under a continental plate, pulling the rest of the plate with it; this is the strongest force.
- Plate movement is the result of convection currents, ridge push, and slab pull working together.
Effects of Plate Movement
- Plate movements cause earthquakes, volcanoes, mountain building, and ocean floor formation.
- These processes are visible in the Philippines through fault lines, trenches, volcanoes, and mountain ranges.
Plate Tectonics in the Philippines: Real-World Examples
- The West Valley Fault (Marikina Valley Fault) causes frequent earthquakes near Metro Manila due to plate movement.
- Taal and Mayon volcanoes form at subduction zones where slab pull and magma formation occur.
- The Philippine and Manila trenches are created by the subduction of oceanic plates.
- Sierra Central and Sierra Madre mountain ranges are formed by plate collision and uplift.
Quick Check: Key Questions and Answers
- Slab pull is the strongest driver of plate motion.
- Ridge push helps move plates apart at mid-ocean ridges.
- Heat from Earth's core creates convection currents in the mantle.
- Earthquakes and volcanoes are effects of plate movement.
- Collision between the Philippine Sea plate and the Eurasian plate causes frequent earthquakes and volcanic eruptions in the Philippines.
Key Terms & Definitions
- Convection Currents — Circular movement in the mantle caused by hot material rising and cool material sinking.
- Ridge Push — Force from gravity pushing plates away from a mid-ocean ridge.
- Slab Pull — Force as a sinking oceanic plate pulls the rest of the plate during subduction.
- Subduction Zone — Area where one tectonic plate sinks under another.
- Fault Line — Break in Earth's crust where plates move and earthquakes can occur.
Action Items / Next Steps
- Review the examples of plate movement effects in the Philippines.
- Study the definitions of convection currents, ridge push, and slab pull for deeper understanding.
- Prepare for questions about plate tectonics and their real-world impacts.