What are the four layers of the earth? 1. Inner core 2. Outer core 3. Mantle 4. Crust Seismologist A scientist who studies earthquakes. Seismograph A machine that records earthquakes Seismogram The piece of paper that the earthquake is recorded upon. A – the distance between the P and S waves is used to figure out how far away the earthquake was. B – the height of the L waves is used to figure out the magnitude (strength) of the earthquake. Richter Scale A scale that compares earthquake destruction and strength Magnitude The strength of an earthquake Aftershock Smaller earthquakes that follow the first San Andreas Fault A famous fault line in California Fault A crack in the earth’s crust where two plates meet each other. What are the three kinds of seismic waves? P, S, and L waves Focus The spot inside the earth where an earthquake starts – where the p,s and L waves start Epicentre The spot on the crust directly above the focus Tsunami A giant wave created by an under water earthquake. Volcano A crack in the earth’s crust with gas, lava or ashes/cinders coming out of it. Vulcanologist A scientist who studies volcanoes 3 kinds of volcanoes Cinder Cones, Shield Cones, and Composite Cones (Stratacone) The largest volcanoes Composite cones The smallest volcanoes Ash/Cinder cones The most explosive volcanoes Composite cones Lava only Shield Cones Cinders/Ash only Cinder cones Lava and cinders and ash Composite cones Caldera The bowl shaped rim of a volcano How many seismographs are needed to pinpoint the location of an earthquake? Three How do we know what is inside the earth? By listening to earthquakes as they pass through the Earth Why is a spinning metal core so important to our survival? It generates the Earth’s magnetic field which protects us from solar radiation. Theory of Continental Drift The theory that stated that the continents slowly drifted apart over millions of years to their current day position. Alfred Wegener German scientist who came up with the theory of continental drift Pangaea The super continent that existed 200 million years ago. What are 4 pieces of evidence that Wegener had to support his theory? The continents of Africa and South America look like they fit together. Fossils of the same animals on widely separated continents. Glaciers on the equator and tropical swamps in the arctic. Mountain ranges that connect on both sides of the ocean Theory of Plate Tectonics The current theory that says the earth’s crust is broken into large jigsaw puzzle pieces that are slowly moving (as they move they create volcanoes, earthquakes and mountains) Where do earthquakes, volcanoes and mountains occur? Along the edges of tectonic plates What are the three kinds of plate boundaries? 1.Transform faults – plates sliding past each other 2.Divergent boundary – plates separating from each other – making new crust 3.Convergent boundary – plates colliding – destroying old crust J. Tuzo Wilson Canadian scientist who helped form Theory of Plate Tetonics.