HOW THE WORLD WORKS (PART II) INSIDE THE EARTH AND PLATE TECTONICS

AGENDA Inside the Center of the Earth Tectonic Plate Movements DISASTER STRIKES!

A QUICK RECAP Alfred Wegener creates theory, supported by Wilson’s “how it happens”, determining: 300 million years ago, all Earth’s land formed the supercontinent: Pangaea. 200 million years ago, Pangaea breaks up due to Continental Drift.

INSIDE THE EARTH SO WHAT’S UP IN THE WAY-DOWN UNDER ANYWAYS?

THE EARTH WITH NO WATER…

THE EARTH WITH NO WATER OR LIFE…

WHAT CAN WE CONCLUDE? There are many mountains and deep valleys on ocean floors. Water covers most of the Earth. If there’s no water, then there’s no life!

JOURNEY TO THE CENTER OF THE EARTH! Queue the video!

STARTED FROM THE MIDDLE, NOW WE ‘ERE! Crust: approx. 5 – 50 km thick Lithosphere: up to 100 km thick Cold and (relatively) fragile Granite and/or Basalt ‘ERE Approximately 2,900km thick Upper mantle: 600-700 km Lower Mantle: 2000-2200 km hot and molten (magma!) magnesium and silicon Approximately 2,000 km thick Temperature of 3,000-4,000 °C Liquid nickel and iron Approximately 1,200 km thick Temperature of 5,000-6,000 °C Solid nickel and iron Source of magnetic field Middle: 6,378 km

PLATE TECTONICS THEY’RE WHAT’S HOT AND ON THE MOVE!

YOU TRY IT! In partners, open your binder flat and line it up next to the edge of your partner’s open binder. Push the binders together firmly without breaking anything (or anyone!).

WHAT HAPPENED? One binder slipped under the other? This is how plate subduction works! One binder buckled up and bent? This is how fold mountains are created!

3 TYPES OF PLATE MOVEMENT Convergent boundaries involve tectonic plates moving towards each other. It is typical for one plate to descend under the other in a process known as subduction.

3 TYPES OF PLATE MOVEMENT Divergent boundaries involve tectonic plates moving away from each other. These often form rift or large ridges.

3 TYPES OF PLATE MOVEMENT Transform boundaries involve two plates scraping each other while moving in opposite directions. (Or sometimes moving in the same direction at different speeds!)

WATCH IT IN ACTION! Check out this site for an interactive “inside the earth” experience and test your knowledge! Now for some awesome tectonic Flash clips! https://www.learner.org/interactives/dynamicearth/index.html

AN EXAMPLE! The Indian subcontinent is subducting under the Eurasian Plate, resulting in the building of the Himalaya Mountains… Yes, Mount Everest is always getting taller!

EVEREST GETS TALLER…

PLATE BOUNDARIES IN SUMMARY

THE WORLD’S FASTEST PLATE! The Nazca Plate is currently moving at a rate of 16cm / year! Why might it be moving faster than other plates?

SUBDUCTION DRAG…

DISASTER STRIKES! WHY WE HAVE EARTHQUAKES AND VOLCANOS

VOLCANOS IN ACTION ANIMATION

EARTHQUAKES IN ACTION VIDEO

Some results of earthquakes…

THE QUAKE-O-METER! RICHTER SCALE: EFFECTS: Less than 3.5 Generally not felt, but recorded. 3.5-5.4 Often felt, but rarely causes damage. Under 6.0 At most slight damage to well-designed buildings. 6.1-6.9 Can be destructive in areas up to about 100 kilometers across. 7.0-7.9 Major earthquake. Can cause serious damage over larger areas. 8 or greater Great earthquake. Can cause serious damage in areas several hundred km across.