Earth and Space Science 2015 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 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 crack or fissure along or beneath the surface of the Crust. Movement on either side of or along the fault can start an earthquake. Major fault lines can occur on or along plate boundaries.
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 (Oceanic, Continental) and the thin, hard, 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.
Plate - A large section of Earth that includes the Crust and the upper section of the Mantle (Lithosphere) 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 an opposite direction.
Seismograph - Records and graphs Seismic waves (Primary/Secondary/Surface) that occurs 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 (the denser oceanic crust subducts). - 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 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). 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.
Describe changes of the Earth s surface at subduction zones. -Mountains and volcanoes form. - Frequent earthquakes deep in the Mantle. -Infrequent earthquakes near the surface. - 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 10. - 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 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.