Chapter 5 Landform- a physical feature on Earth’s surface. Abyssal Plain- wide, flat area of the ocean floor. Trenches- deepest parts of the ocean floor. Rift Valley- indentation along tops of underwater mountains. Atmosphere- includes all the gases around Earth. Hydrosphere- all of Earth’s water. Crust- rocky layer of Earth. Mantle- Earth’s interior below the crust. Inner Core- deep inside Earth; made of solid metals. Diagrams: Geologist- a scientist who examines rocks to find out about Earth’s history and structure. Theory that the continents slowly moved to the position where they are today. Rock types- are the same in Eastern South America and western Africa. Faults- deep cracks in the Earth’s crust. Movement along these cracks can form mountains. Folded mountains: The Himalayan Mountains Fault-block Mountains: The Sierra Nevada Mountains Volcano- an opening in Earth’s crust. Most likely to form at plate boundaries. Tend to erupt when one plate is pushed under another plate. Rocks in the mantle melt and magma forms in a chamber. Pressure in the chamber grows and the magma is forced upward through cracks. Magma reaching the Earth’s surface is called lava. Form when thick lava is thrown into the air and falls as chunks or cinders. Hot Spot- a stationary pool of magma below Earth’s crust. As the plate moves, new islands are formed. Earthquake- sudden movement of the Earth’s crust. Waves move like ripples on a pond, making the surface and anything on it move. Earthquakes happen along the boundaries of tectonic plates. Magnitude- a measure of the amount of energy released by an earthquake. Richter Scale- measures the magnitude at the epicenter. Mercalli Scale- measures what people felt and what happened to objects at a specific location. Tsunami- a huge wave, usually occurring after an underwater earthquake. Chemical weathering- acid rain can wear away at stone and metals. Erosion- weathered rock is moved from one place to another place. As water is running faster, it can wash away soil and rock. When the water slows, the water will drop the material in another place.