2What Makes the Crust Move? Earth’s crust is constantly moving, if not in one place then in another. Sometimes it moves quickly enough to be seen and felt (such as an earthquake).Earthquake
3Earthquakes are related to cracks in the crust called faults Earthquakes are related to cracks in the crust called faults. The faults may have formed from earlier earthquakes. Sometimes they form while the earthquake happens.
4Earth’s VibrationsDuring an earthquake vibrations travel through the crust. The farther away people are from the earthquake, the harder it is for them to feel the vibrations.The vibrations that move through the Earth’s layers are called seismic waves.These vibrations are measured on a machine called a seismograph.Fault
5SeismographA seismograph, or seismometer, is an instrument used to detect and record earthquakes. Generally, it consists of a mass attached to a fixed base. During an earthquake, the base moves and the mass does not.
6Not all motion happens along faults. Often, layers of the crust bend Not all motion happens along faults. Often, layers of the crust bend. Bending, like motion along a fault, may happen gradually over time.To measure crust movement, surveyors measure elevation—how high a place is above sea level.They leave plaques called bench marks that tell the exact location and elevation of a place. When some bench marks are remeasured, they are found to have risen or sunk.
7Geologists are scientists who study the Earth. Tools of the TradeGeologist Brunton Pocket TransitGeologist Estwing Rock HammerGeologist Outfit
8Earth’s Layers The Earth is composed of four different layers. 1. Crust – Earth’s outermost layer that is thinnest under the oceans and thickest through the mountains. 2. Mantle – largest layer of Earth’s interior that lies above the outer core and is solid yet flows slowly. 3. Outer core – layer of Earth that lies above the inner core and is thought to be composed mostly of molten metal. 4. Inner core – solid, innermost layer of Earth’s interior that is the hottest part of the Earth and experiences the greatest amount of pressure.
9Clues to Earth’s Interior Scientist or geologist use indirect observations to gather clues about what the Earth’s interior is made of and how it is structured. Geologist studies:1. Waves Rock Clues
10Earth’s PlatesThe rigid, upper part of Earth’s mantle and the crust is called the lithosphere.
11Plates – The moving pieces of the relatively rigid outer layer of the Earth (the lithosphere), made up of the crust and upper mantle, which contain the continents and ocean floors.
12Plate Boundaries (3 types): Plate boundaries – the places where the edges of different plates meet. 1. Mountains – landforms that extends above the surrounding terrain. 2. Rift valleys – elongated depressions. 3. Faults – large fracture in rocks along which movement occurs (Fracture – a break in a rock formation due to structural stresses.)
13The movements of the plates are fairly slow, often taking more than a year to creep a few centimeters. Plates Slow Creep
15Subduction – a type of plate movement that occurs when one plate sinks beneath another plate.
16Three Types of Convergent Plate Boundaries Continental-continental collisionsContinental-oceanic collisionsOceanic-oceanic collisions
17Uplift of Earth’s Crust There are four main types of mountains: 1. Fault-block 2. Folded 3. Upwarped 4. Volcanic
18Fault-Block Mountains Fault-block mountains form from pulling forces. They are sharp jagged mountains made of huge, tilted blocks of rock that are separated from surrounding rock by faults and form because of pulling forces. (Fault – large fracture in rock along which movement occurs.)
19Folded MountainsFolded mountains are mountains formed by the folding of rock layers caused by compression forces.
20Upwarped MountainsUpwarped mountains form when forces inside Earth push up the crust.
21Volcanic MountainsVolcanic mountains are mountains that forms when magma is forced upward and flows onto Earth’s surface.
24What type of mountains make up the Hawaiian Islands? Volcanic Mountains
25Other Types Of UpliftAccording to the principal of isostasy, the crust and lithosphere are able to float on the mantle.The principle of isostasy relates to the buoyancy of rocks. (Buoyancy is the tendency of a body to float or rise when submerged in a fluid.)
26Does all of this drive you apes? The EndDoes all of this drive you apes?