LITHOSPHERE The solid rock portion of the Earth’s surface

Continental Drift Theory Alfred Wegner – 1912 Earth was once a supercontinent called Pangaea Divided and slowly drifted apart over millions of years

Convection Currents Rock in the asthenosphere is hot enough to flow slowly Heated rock moves up toward the lithosphere, cools, and circulates downward Riding above this circulation system are the tectonic plates

Plate Tectonics

Plate Movement & Boundaries Divergent BoundaryTransform Boundary Convergent – Collision BoundaryConvergent – Subduction Boundary

Folds and Faults When two plates meet, they can cause folding and cracking of the rock. If the rock is flexible it will fold and bend If the rock is not flexible it will crack or fracture, creating a fault

Earthquakes As plates rub together the earths shakes. Nearly 95% of all earthquakes occur at plate boundaries Video Seismograph: a special device used to measure the size of waves created by earthquakes The Richter Scale: uses information collected by seismographs to determine the relative strength of an earthquake. A tsunami can happen when an earthquake occurs in the ocean Video

Volcanoes Magma, gases, and water from the lower part of the crust or the mantle collect in underground chambers Eventually these materials pour out of a weak point in the earth’s surface called a volcano. Most volcanoes are found along plate boundaries When magma hits earth’s surface it is called lava. Papua New Guinea volcano video

Ring of Fire A zone around the rim of the pacific plate where the vast majority of volcanos are located.