Earth and Space Science. Semester 2 Exam Review. Part 1. - Convection currents circulate in the Asthenosphere located in the Upper Mantle.

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1 Earth and Space Science Semester 2 Exam Review Part 1 Convection -A form of heat transfer. - Convection currents circulate in the Asthenosphere located in the Upper Mantle. - Source of heat is from the Earth s Interior and is the driving force for Lithospheric Plate movement. Convergence - Lithospheric plates converge at a Convergent Plate Boundary (Oceanic-Continental, Continental-Continental and Oceanic-Oceanic convergence). -With the exception of Continental-Continental convergence, the subducting plate is consumed and recycled as it descends into the Mantle. Divergence -Lithospheric Plates are moving in opposite directions. -The creation of oceanic crust and Sea-floor spreading occurs at mid-ocean ridges. -Rift Valleys occur along Continental Divergent Boundaries. Earthquake Fault -A sudden movement or faulting that occurs beneath the Earth s surface that causes powerful vibrations or seismic waves of energy. - A break in Earth s crust where masses of rock slip by each other.

2 Hot Spot - A large pool or reservoir of magma located in the Mantle and beneath a moving Oceanic or Continental plate. -Hawaiian Islands, Emperor Sea Mount Chain and Yellowstone Park are examples. -Hot Spots can also occur at Divergent Plate Boundaries such as Iceland. Island Chain - Volcanic islands that were produced by Hot Spots. Lithosphere -Broken up into large plates that move slowly over the Earth s surface. -It consists of the entire Crust and the thin upper layer of the Mantle located above the Asthenosphere. Mantle -The largest section of Earth. - Located between the Outer Core and the Crust. -Convection Currents circulate in the Asthenosphere located in the upper part of the Mantle. Mid-ocean ridge -A low lying mountain range that occurs alongside a Divergent Plate Boundary. - Oceanic crust and Sea-Floor Spreading is produced on both sides of the boundary. - Iceland is located on both sides of the Mid-Atlantic Ridge.

3 Plate - A large section of Earth that includes the Crust and the upper section of the Mantle that moves and interacts with other plates at plate boundaries. Plate boundary - A location on the Earth s crust where two or more Lithospheric Plates interact. Plate Tectonics -The study of forces and processes that cause Lithospheric plates to interact. - Forces and processes include earthquakes, volcanoes, subduction, mountains and sea-floor spreading. Rift Valley - A valley located along a divergent plate boundary that occurs between Continental Plates. San Andreas Fault - An example of a Transform Boundary. - Located between central and southern California. - One side of the fault (Western) is the Pacific Plate while the other side of the fault (Eastern) is the North American Plate. Sea Floor Spreading - Occurs on both sides of a Divergent Plate Boundary. - Rising molten material creates oceanic crust (denser than Continental crust) that moves in opposite directions.

4 Seismograph - A machine that records and graphs Seismic waves (P/Sec./Sur) that occur during an earthquake. Subduction - Occurs when an oceanic crust subducts or moves underneath a continental (less dense) and into the Mantle. -Subduction can also occur between two oceanic crusts. - An oceanic trench occurs prior to the subduction. Transform Boundary -Where two plates move adjacent to one another and in opposite directions. -The San Andreas Fault is an example. -Shallow earthquakes often occur along the boundary. Volcano -A mountain that is formed by lava. -Commonly occurs at a Hot Spot, or at a Subduction Zone where a Convergent Boundary exists or at a Divergent Plate Boundary. How does heat flow in the Earth s interior affect the circulation of the mantle? - The heat from the Earth s interior (Outer and Inner Cores) rises and circulates as Convection Currents in the Asthenosphere (Upper part of the mantle that is not as Solid as the lower part).

5 How does the same heat flow affect plate movement and volcanoes? - These Convection currents soften material in the Asthenosphere and are the driving force behind plate motion. Give evidence to support continental drift, sea floor spreading and plate tectonics. - Discovery of mid-ocean ridges and changes in the magnetic striping of rocks at mid-ocean ridges. - Trenches followed by subduction zones, mountains and volcanoes. - Plant and animal fossils. - Glaciation marks or scars. - Fracture zones. - Similarities of distant mountain ranges. - Similarities of plant and animal fossils separated by great distance. - Shapes of Continents appear to fit together like a puzzle piece. Examples of earth features caused by sea floor spreading and plate tectonics. - Mid ocean ridges. - Trenches, subduction zones, mountains, volcanoes and earthquakes. Compare the three types of plate boundaries. Convergent Divergent Transform Oceanic Continental Oceanic-Oceanic Continental-Continental Mid- ocean ridge (Sea-floor Spreading) Continental-Continental (Rift Valley) Plates slide by each other (adjacent) without creating or consuming lithosphere.

6 Describe changes of the Earth s surface at subduction zones. -Mountains and volcanoes form. - Frequent earthquakes deep in the Mantle. - An oceanic trench forms near the coastline. Describe how island chains are produced by Hot Spots. -As a plate moves slowly over a large reservoir of magma in the mantle, it produces volcanic islands above. -As the islands move with the plate, the Hot Spot continues to produce volcanic islands. - At present, there is a new seamount rising off the SE coast of Hawaii. What are the factors that influence magnitude and intensity? -Magnitude is determined by the strength and duration of the primary, secondary and surface waves. -Magnitude is measured by the Richter Scale that increases by an exponential of A 9 is 10x s more powerful than an 8 and 100x s more powerful than a 7. -Intensity is measured by the Mercalli Scale which measures the damage that an earthquake can cause. -Structure design, building materials, proximity to the epicenter and type of land formation (loose sand, strong bedrock) can influence the amount of damaged caused by an earthquake. What does a volcano tell us about what is happening in the Earth s Interior? -The Earth releases tremendous amounts of stored energy from its Inner and Outer Cores in a controlled manner by way of tectonic processes. - These processes create changes to existing land and produce new land formation. -Volcanoes can indicate the presence of subduction zones in the mantle or hot spots beneath a moving plate.

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