Presentation on theme: "Plate Tectonics Notes # 2. Tsunamis: means “ wave in the harbor” in. When there is an earthquake underwater, the sea floor may drop down suddenly due."— Presentation transcript:
Plate Tectonics Notes # 2
Tsunamis: means “ wave in the harbor” in. When there is an earthquake underwater, the sea floor may drop down suddenly due to. The result is a wave that can reach 100 feet (30 Meters) or more in height. As the approaching tsunami rises up in the water, it pulls the water near the shore with it, sort of like lifting a flat bag off the ground. As you lift higher, the edges of the bag move towards where you are lifting. Japanese FAULTING
Zones of Earth- pg. 10 ESRT!
Discontinuity Discontinuity : a place located at the boundaries between the and mantle, the mantle and, and outer core and where the density of the rocks increases dramatically (as you move inwards). We have located these discontinuities by studying seismic wave, and refraction/reflection of the waves at these boundaries. THIS IS HOW WE KNOW WHAT THE LAYERS OF THE EARTH ARE! CRUST INNER CORE OUTER CORE PATTERNS
Examples of a discontinuity…
CRUST The crust is the outermost part of the earth below the atmosphere or hydrosphere. Composed or made up of mostly solid including all the soil and weathered and eroded rock. including all the soil and weathered and eroded rock. - The crust is solid, cold, and brittle ( breaks easily). ROCKS
MANTLE Mantle: the mantle is below the crust. The thickest zone that contains approximately 80% of Earth’s volume. The mantle is divided into three different layers. Mantle: the mantle is below the crust. The thickest zone that contains approximately 80% of Earth’s volume. The mantle is divided into three different layers. Rigid Mantle Rigid Mantle Asthenosphere Asthenosphere Stiffer Mantle Stiffer Mantle
RIGID MANTLE RIGID MANTLE: this is part of the mantle that is similar to the solid rocks in the crust. Due to this fact it travels around when the plates move with the __________. The crust and this rigid part of the mantle are collectively called the lithosphere. In between the crust and the rigid mantle is a region called the MOHO. This represents a boundary where the rocks _______________ rapidly in density. Even though there are density differences the crust and mantle are considered a single part (THE LITHOSPHERE) and move together! CRUST INCREASE
Asthenosphere (Plastic Mantle) ASTHENOSPHERE (PLASTIC MANTLE)- called the plastic mantle because it behaves and flows like silly putty, bread dough, or. This zone was discovered because it was found that seismic waves decrease in velocity from 100km to 700km below the Earth’s surface. (Seismic waves travel more slowly through liquids than solids). It is a plastic-like portion of the upper mantle that is partly. SEE ESRT PG 10! The of the asthenosphere is above the melting point indicating that it is melted. Due to its “plasticky” nature, the allows the plates of the lithosphere to float around, move, pull apart, or into each other. HONEY MELTED TEMPERATURE ASTHENOSPHERE CRASH
Stiffer Mantle Stiffer Mantle: this part is solid again until you get to the ………………..
Outer Core OUTER CORE- it is a __________ and we know this because NO ___- waves will pass through it! There is also a major drop in P-wave velocity indicating that the wave has moved from a _________(medium mantle) to a ___________medium (outer core). LIQUID S SOLID LIQUID
Inner Core INNER CORE: very dense _____________ composed of nickel and iron also. Believed to be a solid due to the observation that P-wave velocity ___________ in this region. SOLID INCREASES
What happens to the P and S waves as they travel through the layers of earth?
Composition of outer and inner cores composed or made up of mostly nickel and iron because when the Earth was forming the denser materials (like iron and nickel) sank down to the middle.
EARTHS CRUST Continental Crust Continental Crust-composed of granitic rocks with an average density of _____ g/cm 3 and makes up the continents. Thicker than oceanic crust. Thickest under ___________________ while thinnest under coastal regions. 2.7 MOUNTAINS
Oceanic Crust Oceanic Crust: composed of basaltic rocks with and average density of ____ g/cm 3. Sometimes as thin as 4 miles (about 20,000 ft) in places like mid- ocean ______. *** Remember oceanic crust is more dense than continental crust! You will need to know this for our next topic that we will be learning about!! 3.0 RIDGES