Appendix 1
In order to teach this unit, an educator will need to address the following concepts and terminology to have a unit that is affective and connected to the purpose of this unit.
Alfred Wagener- He is remembered for his contribution to geology, for the theory of the continental drift. He named and described Pangaea and provided strong arguments as a supercontinent. He was not the first to recognize the separation of the continents, but he was the individual, that till his death tried to prove his theory.
Harry Hess-He was a professor of geology at Princeton University. Even when serving in WWII, he conducted research-using sonar. He was very influential in setting the stage for the emerging plate-tectonics theory in the early 1960s. He believed in many of the observations Wegener used in defending his theory of continental drift, but he had very different views about large-scale movements of the Earth. He said that the evidence came from the mapping of the sea floor. (due to WWII submarines)
Pangea- meaning "all earth" supposedly covered about half the Earth and was completely surrounded by the ocean. It then began to break apart. The movement of the continents took millions of years to be where they are today.
Plate Tectonics Theory- This theory is considered a relative new theory. Alfred Wegener proposed this theory in 1915. The theory is stated that the Earth is broken up into large plates. The size and the proportion change over time. Where the plates move against each other, one will usually find intense geologic events: volcanoes, earthquakes, and mountain building.
Sea Floor Spreading-In the theory of plate tectonics, the process by which new oceanic crust is formed by the convective upwelling of magma at mid-ocean ridges, resulting in the continuous lateral displacement of existing oceanic crust.
Continental Drift-The movement, formation, or re-formation of continents described by the theory of plate tectonics. It is referred to the movement of the Earth''s Continents.
Transform Plate Boundaries -This boundary is located where two plates slide past one another. The fracture zone that forms a transform plate boundary is known as a transform fault. Most transform faults are found in the ocean basin and connect offsets in the mid-ocean ridges. A smaller number connect mid-ocean ridges and seduction zones.
Convergent Plate Boundaries- This boundary is located where lithosphere plates are moving towards one another. The plate collisions that occur in these areas can produce earthquakes, volcanic activity and crystal deformation.
Divergent Plate Boundaries- This boundary is located where plates are moving away from one another. This occurs above rising convection currents. The rising current pushes up on the bottom of the lithosphere, lifting it and flowing laterally beneath it. This lateral flow causes the plate material above to be dragged along in the direction of flow. At the crest of the uplift, the overlying plate is stretched thin, breaks and pulls apart.
Strike-Slip Fault- The strike faults are either right or left laterals. The fault ruptures as the ground generates vibrations-or waves-in the rock that we feel as ground shaking. Faults are weaknesses in the rock and therefore earthquakes tend to occur over and over along the same faults. For strike-slip faults, the rupture is nearly vertical and during an earthquake one side slides past the other. The San Andreas Fault is a strike-slip fault formed where two parts of the earths crust (plates) slide past each other.
Reverse Faults- This type of fault forms when the hanging wall moves up. The forces creating reverse faults are compressional, pushing the sides together.
Normal Fault-This type of fault forms when the hanging wall drops down. The forces that create normal faults are pulling the sides apart, or extensional.
Primary Waves-Another name for this wave is-P waves or compression waves. The P- waves are the first to arrive at the surface during an earthquake. They can travel through solid, liquid and gas, and so will pass completely through the body of the earth. As they travel through rock, the waves move tiny rock particles back and forth—pushing them apart and then back together—in line with the direction the wave is traveling. These waves typically arrive at the surface as an abrupt thud.
Secondary Waves-Another name for this wave is-S waves or shears waves. They actually lag a little behind the P waves. As these waves move, they displace rock particles outward, pushing them perpendicular to the path of the waves. This results in the first period of rolling associated with earthquakes. Unlike P waves, S waves don''t move straight through the earth. They only travel through solid material, and so are stopped at the liquid layer in the earth''s core.
Love Waves-Another name for this wave is-L waves. They are actually secondary waves but they movesidetosideinsteadof upanddown.
Mercalli Scale- this scale was incise away to measure the strength of an earthquake. Invented by Giuseppe Mercalli in 1902, this scale uses the observations of the people who experienced the earthquake to estimate its intensity. The Mercalli scale isn''t considered as scientific as the Richter scale. Some witnesses of the earthquake might exaggerate just how bad things were during the earthquake and you may not find two witnesses who agree on what happened; everybody will say something different. The amount of damage caused by the earthquake may not accurately record how strong it was either.
Richter- This type of measurement was invented by Charles F. Richter in 1934. The magnitude of most earthquakes is measured on the Richter scale, invented by Charles F. Richter in 1934. The Richter magnitude is calculated from the amplitude of the largest seismic wave recorded for the earthquake, no matter what type of wave was the strongest. The Richter magnitudes are based on a logarithmic scale (base 10). What this means is that for each whole number you go up on the Richter scale, the amplitude of the ground motion recorded by a seismograph goes up ten times.
Liquefaction- Liquefaction is a phenomenon in which the strength and stiffness of a soil is reduced by earthquake shaking or other rapid loading. Liquefaction and related phenomena have been responsible for tremendous amounts of damage in historical earthquakes around the world. Liquefaction occurs in saturated soils, that is, soils in which the space between individual particles is completely filled with water. This water exerts a pressure on the soil particles that influences how tightly the particles themselves are pressed together. Prior to an earthquake, the water pressure is relatively low. However, earthquake shaking can cause the water pressure to increase to the point where the soil particles can readily move with respect to each other.
Truss- There is a variety of trusses that can be identified in numerous bridges throughout the world.
King Post Truss-It is the simplest form. This truss has been adapted to support shorter bridge spans.
Queen Post Truss-It actually adds a horizontal top chord to achieve a larger span.
Lattice Truss-It is easy to construct, but labor intense.
Vierendeel Truss-It is a rectangular system of structural elements capable of transferring loads by imposing bending moments on all structural elements.
Arch-It is intriguing in that they are truly a natural form of bridge. It is the shape of the structure that gives it its strength. An arch bridge requires end supports or abutments.
Beam-This bridge is basically a rigid horizontal structure that is resting on two piers, one at each end. The piers directly support the weight of the bridge and any traffic on it. The weight is traveling directly downward.
Cantilever-A projecting beam or member supported at only one end: as a:a bracket-shaped member supporting a balcony or a cornice b:either of the two beams or trusses that project from piers toward each other and support a suspended connecting member.
Suspension-A suspension bridge is one where cables (or ropes or chains) are strung across the river (or whatever the obstacle happens to be) and the deck is suspended from these cables. Modern suspension bridges have two tall towers overwhich the cables are strung. Thus, the towers are supporting the majority of the roadway's weight.
Tension- It is a force that acts to expand or lengthen the object on which it is applied.
Compression- It is a force that acts to compress or shorten the object on which it is applied.
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