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43 Cards in this Set
- Front
- Back
this states that the older strata or sedimentary layers are at the bottom in a series and the younger layers are at the top
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Principle of Superposition
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rock layers are laid down in an essentially horizontal manner.
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Principle of Horizontality
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sediments extend laterally in all directionsuntil they extended to the edges of the basin in which they are deposited
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Principle of Lateral Continuity
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states that an igneous intrusion or fault mustbe younger than the rocks it intrudes or displaces
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Principle of cross-cutting relationships
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states that the fragments or inclusions of onerock contained in another rock layer are older than the rock layer itself
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Principle of Inclusion
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a surface of nondeposition or erosion that separatesyounger strata from older rocks. It represents a break in our record ofgeologic time.
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Unconformities
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a surface of erosion or non-deposition betweenyounger and older beds that are parallel to one another. ,4*�_v��
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Disconformities
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an erosional surface on tilted or folded strataover which younger strata have been deposited. nt4*�_u��
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Angulare unconformities
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an erosional surface cut into a metamorphic origneous rock layer and overlaid by younger sedimentary rock strata. oung*ic
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Non-Conformity
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rock layers are squeezed
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Compressional Stress
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forces acting in opposite directions.
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Tension
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lengthening the rock layer and ultimatelypulling it apart
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Shear Stress
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rocks are stressed and deformed but return backto their original shape
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Elastic
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rocks are stressed past their elastic limit andremain in their new deformed shape
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Plastic
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the direction of a line formed by theintersections of a horizontal plane and an incline plane
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Strike
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A measure of the maximum angular deviation of anincline plane with the horizontal. It is measured perpendicular to the strike
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Dip
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A fault in which the hanging wall has moved downrelative to the foot wall.
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normal fault |
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a fault in which the hanging wall has moved uprelative to the foot wall
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Reverse Fault
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fault where the hanging wall is bounded by twofoot walls, one on either side of the hanging wall block. The hanging wall hasmoved down relative to the two foot walls
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Graben Fault
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Fault where the foot wall is bound by twohanging wall, one on either side of the footwall. The footwall is moved uprelative to the two hanging walls
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Horst Fault |
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a bend or a flexure in an otherwise horizontalor uniformly dipping rock layers
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Fold |
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a fold where the rock layers are arched upward
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Anticlyne |
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Downward folded rock layer
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Syncline |
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A plane that cuts the fold in half
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axial plane |
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One half of a fold (created by the axial plane)
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Limb |
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A line formed by the intersection of axial planeand the folded layers
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fold axis |
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the axial plane is vertical and each limb dipsat the same angletr!y
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symmetric fold |
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the axial plane is incline and the limbs dip atdifferent angles?_ �?y�i
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Asymmetric fold |
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a fold where the fold axis is inclined to thesurrounding layers, so it appears to be plunging into the surrounding rocklayers
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Plunging fold |
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a type of asymmetric fold in which axial planeis horizontal
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Recumbent fold |
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vibration of the earth caused by a suddenrelease of energy, usually as a result of faulting, which involves thedisplacement of rocks along fractures
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Earthquake |
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rocks on either side of a fault where motion istaking place, will bend or become deformed. When the rocks reach their breakingpoint, they break and snap back to their original deformed shape, releasingenergy in the process. ��W
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elastic rebound theory |
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the instrument that detects, records andmeasures the various vibrations produced by a earthquake. tures.R �2v�i
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seismagraph |
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the record made by a seismograph
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seismogram |
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the location within the earths crust wheremotion or rupture takes place and energy is first released. W
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Focus |
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the point on the earths surface locatedvertically above the focus-EndFra^ �>z�i
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Epicenter |
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waves produced by earthquakes are either bodywaves or surface wavesndFra^ �>z�i
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Seismic Waves |
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primary waves the fastest seismic waves and cantravel through solids liquids and gasses. This type of wave is a compressionalwave
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p-waves |
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secondary waves that can only travel throughsolidse of wX �8x�i
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s-waves |
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slower of the two surface waves. These behavelike a water wave in which particles move in an elliptical pattern along avertical plane perpendicular to the direction of the motion of the wave] �=I�
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R-waves |
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similar to the motion of an s-wave but the particlesof the material move back and forth along a horizontal plane perpendicular tothe direction of wave travelFY �9M�
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L-waves |
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a qualitative subject measurement of theearthquake based on the amount and kind of damage buildings and surroundinggeologic structure-D �$r�
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Intensity |
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a qualitative comparison of the amount of energyreleased by an earthquake at its source. It is an open ended scale beginning with1. It is a base -10 logarithmic scale used to compare the amplitude of EQ’s.each whole number EQ has 10 fold the amount of energy than the previous whole numberon the scale. S!2X
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Magnitude |