Science 4th QE

• Crust - The thin outermost layer of the geosphere
• Oceanic Crust - Crust covered by the ocean water
• Core - The innermost part of Earth composed mainly of iron and nickel
• Continental Crust - Crust which is covered by soil
• Lithosphere - The rigid upper portion of the mantle that includes the crust
• Asthenosphere - The upper part of the mantle that is hot and flowing
• Mantle - Lies below the crust. It is made of very hot and very slow-flowing solid rock.
• Core - The center of the Earth. It is made of iron and nickel and is the densest layer.
• Tectonic Plates - Plates that are always moving but at a very slow rate
• Plate Tectonics - The movement of the plates
• Seismic Waves - Vibrations generated by earthquakes or explosions that travel through the Earth's interior.
• Seismologists - Geophysicists who are experts in earthquakes
• Richter Scale - A scale used to measure the intensity of an earthquake based on its seismic waves.
• Seismic Wave - An elastic wave generated by an earthquake or an explosion.
• Body Waves - Seismic waves that travel through the Earth's interior
• Primary Waves - Fastest seismic waves. Moves the material in a path parallel to the direction of movement.
• Secondary Waves - Slower than P-waves. Can only travel through solids and they cannot pass through liquids
• Surface Waves - Travel along the surface of the earth, causing ground shaking during an earthquake.
• Love Waves - Move up and down as well as sideways. They are slower than S-waves but faster than L-waves.
• Rayleigh Waves - The most destructive type of seismic wave. It moves up and down while also moving from side to side.
• Andrija Mohorovicic - Discovered that seismic waves from distant earthquakes reach the seismographs faster than those from nearby earthquakes.
• Mohorovicic Discontinuity - The boundary between the mantle and crust
• Beno Gutenberg - Discovered an abrupt change in seismic waves from 2,900 km below the surface that recorded by seismographs all over the world.
• Gutenberg Discontinuity - The Core and Mantle boundary
• Elastic Rebound Theory - Explains the occurrence of earthquakes
• Elastic rebound - The return of the rock to its original shape after elastic deformation
• Focus - Spot within the crust where a fault shifts or moves
• Hypocenter - Spot directly above the focus
• Epicenter - The spot on the ground where the movement or shaking is felt during an earthquake
• Fault - The crack that forms when large blocks of rock break and move past each other.
• Fault Blocks - Blocks of rock on either side of the fault
• Fault Plane - The location where two fault blocks meet
• Fault Dip - The angle between the fault plane and the horizontal plane.
• Dip-Slip Fault - Type of fault when the fault dip is inclined relative to the horizontal surface of the ground
• Normal Fault - Formed when the stress on the rock pulls it apart causing it to stretch.
• Reverse Fault - Created when the stress pushes the rocks toward each other.
• Thrust Fault - A special type of reverse fault wherein the fracture is nearly horizontal
• Strike-Slip Fault - The rocks on both sides of the fault move horizontally but in opposite directions.\
• Transform Fault - Develops from the many sections of the Mid-Oceanic ridge formed by the magma that forces itself to the oceanic crust and becomes part of the ocean floor.
• Modified Mercalli Scale - Used to describe the intensity of an earthquake