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205 Cards in this Set
- Front
- Back
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Any change in shape or volume or both of rocks is what?
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Deformation
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The force applied to a given area of rock is?
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stress
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_______ results from forces acting along the same line bu in opposite directions?
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tension
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In _____________ forces act parallel to one another but in opposite directions, resulting in deformation by displacement along closely spaced planes
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shear stress
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__________ causes shortening of rock layers by folding or faulting.
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compression
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_______ lengthens rock layers and causes faulting.
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tension
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________ causes deformation by displacement along closely spaced planes.
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shear stress
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What is this describing?
Material is deformed but at stresses that are lower than the yield strength. If stress is relieved, strain is recovered. |
elastic recoverable (Ductile)
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What is this describing?
Applied stress exceeds yield strength, therefore material is permanently deformed. |
elastic non-recoverable (Ductile)
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What is this describing?
Applied stress exceeds fail strength, therefore material fractures to resolve internal strain. |
brittle (non-ductile)
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Compass bearing, with reference to Magnetic North =
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strike
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Tilt angle with reference to horizontal =
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dip
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Folds form in response to what?
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compression
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Up folds are characteristics of what?
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anticlines
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Youngest rocks on the outside of the fold and oldest rocks in the middle of the fold is a characteristic of what?
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anticlines
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Down folds are characteristics of what?
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synclines
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Oldest rocks on the outside of the fold and youngest rocks in the middle of the fold are characteristics of what?
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synclines
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A fold with an inclined axis is called a what?
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plunging fold
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What are the oval and circular equivalents of anticlines and synclines?
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domes and basins
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The circular fold in which all strata dip toward a central point, and the youngest exposed rocks are in the center is a what?
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basin
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A rather circular geologic structure in which all strata dip away from a central point, and the oldest exposes rocks are at the the center is called what?
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dome
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The reverse of a dome is a what?
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basin
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What is the closest dome?
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Nashville
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A fracture along which no movement has occurred or where movement has been perpendicular to the fracture surface is called what?
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a joint
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A __________ means that the rocks on opposite sides of the fracture surface have not slid up down, or sideways along the fracture surface.
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joint
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Up and Down slip =
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dip
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Side to Side slip =
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strike
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Can't stand on it =
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hanging wall
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Can stand on it=
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foot wall
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Can you tell how the dip and strike slips moved?
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no
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What can you say about Hanging Wall and Foot Wall movements?
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That they either moved up or down
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The line between 2 fault blocks is the _________.
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fault wall
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True or False: You can only tell the last event that happened at the fault.
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True
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On fault the rock on one side of the fracture surface is displaced by relative to the rock on the opposite side of the fracture is called the what?
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fault plane
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When movement takes place along a fault plane, the rocks on opposite sides may be scratched and polished or they may be crushed and shattered into angular blocks forming what?
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fault breccia
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A normal fault =
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extension <--------- ------------->
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Reverse fault =
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compression -------><------
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Thrust fault=
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compressional stress
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If the fault plane dips at less than 45 degrees, it is a _________ fault.
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thrust
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____________ faults can only produce where you have space to stretch the crust out.
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normal faults
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How can you see how much faulting has occurred?
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find the difference in offsets
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reverse faults =
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compressional
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_______ faults are unique and a very low angle reverse fault.
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thrust
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In _________ faults, the crust is pushed back over itself during crustal collisions.
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overthrust
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Strike slip faults =
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shear
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Which fault allows us to tell more history of how many times the fault moved?
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strike slip
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What fault system is not one big fault, it's a series of faults that piggy back off each other until you get a major fault?
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San Andreas
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A dextral strike slip fault is moving to the what?
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right
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In an earthquake the yield point and the fail point are what?
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very close
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In an earthquake, deformation consists of _________ and _________ events.
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elastic and brittle
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On the fault plane at depth is the what?
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focus
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The map location at the surface above the focus is the what?
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epicenter
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The _________ is the first point of rupture on t he fault.
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focus
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Most earthquakes occur at what?
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plate boundaries
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Shallow earthquakes are at what km?
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70
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Deep earthquakes occur at what?
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more than 300 km
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Focal depths are usually around what km?
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100
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How far down is the lithosphere?
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100 km
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What is the epicentral distance from the ocean trench and the depth to the focus beneath the epicenter?
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angle of subduction
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In this zone, there are 2 events happening. The crust is stretching AND subducting.
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Benioff Zone
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What two things do we have to know to find the angle of subduction?
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distance of epicenter from trench and depth of focus
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The qualitative assessment of the kinds of damage done by an earthquake is called what?
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intensity
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The quantitative measure of the amount of energy released by an earthquake is called what?
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magnitude
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What is most important to finding the epicenter of an earthquake?
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p-s time interval
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The P-S time interval will tell us what?
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how far away from the earthquake we are
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P and S waves are __________ waves that travel through the planet.
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body
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R an L waves are __________ waves that travel over the planet surface.
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surface
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______ waves are compression-expansion waves, like sound waves.
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P waves
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What waves have vibrations that move back and forth along the line of propagation?
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P waves
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________ waves are slow traveling shear waves that only travel through solids.
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S-waves
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Which wave has vibrations that move up and down perpendicular to the direction of travel, like shaking a rug?
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S waves
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The Richter scale is __________ ended.
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open
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The _________ scale is a measure of economic and societal cost of an earthquake and was developed in 1902 and modified in 1931 by Wood and Newmann.
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Modified Mercalli Scale
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Magnitude, focal depth, and distance from epicenter control what?
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intensity
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Would you rather be at the epicenter, with the focus 400 km down or 200 km away from the epicenter?
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At the epicenter with the focus 400 km down.
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Duration of shaking, aftershocks, construction type, bedrock type, fire, time of day, early warning all control what?
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intensity
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What does the bulk of the damage after an earthquake?
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fire
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What satellite system gives us an early warning for earthquakes?
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Global Earthquake Satellite System
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____________ can give images of ground height shifts to give a few days early warning for earthquakes.
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InSar (interferometric synthetic aperture radar)
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What was the magnitude and speed of the Indonesia earthquake/tsunami?
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9.0 and traveled at 700 km/hr
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What fault caused a major change in the MS River?
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New Madrid Fault
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What degrees is the P-Wave Shadow zone?
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143-103
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What do the p-waves do inside the earth?
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speed up in the mantle and slow down in the core
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What will happen to seismologists stationed in the p-shadow zone?
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they won't know there was an earthquake
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Does the S- wave go through the core? Why or why not?
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No, doesn't travel through liquid
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What degrees is the S-Wave shadow zone?
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103-103
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What can we tell by the travel of P and S waves throughout our planet?
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the size of the inner and outer core, thickness of crusts
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What is the thickness of the continental crust?
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30 km
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What is the thickness of the ocean crust?
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7 km
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What is the thickness of the lithosphere?
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100 km
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What is the thickness of the mantle?
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2000 km
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What is the thickness of the inner/outer core?
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5150 km
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What is the thickness of the asthenosphere?
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200 km
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According to isostacy, gravity, and magnetism, everything is in a state of what?
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flux
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Isostacy =
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density differences
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Continental blocks flowat on the mantle and have what?
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mountain roots
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Erosion over time results in subsidence of the continental interior and exposure of the root. This happens when a mountain gets eroded. What is this an example of?
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isostacy
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If you add weight to the crust it will what?
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Sink over long periods of time
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If you erode weight from the crust it will what?
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rise over long periods of time
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The mouth of the MS River are sinking because?
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sediments are being deposited
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Isostatic __________ happens over 1000's of years.
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Balance
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If _______ increases, gravity increases.
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mass/ gravity
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As ________ increases, gravity decreases.
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distance
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Size of body and distance from each other is effected by what?
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gravity
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Why do we always see some face of the moon?
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because of gravitational pull
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Every 24 hours we have what in the ocean?
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2 high tides
2 low tides |
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Heavier material that is more dense will have a higher what?
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gravity reading
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___________ is inseparable from magnetic fields.
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electric current
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What creates the magnetic field?
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convection current of the liquid outer core around the solid inner core
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What comes out at the south end of the earth and re-enters at the north end?
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lines of flux
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Earth's magnetic field behaves like a what?
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dipole magnet
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What happens to a compass on the North and South Pole?
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it doesn't work for geographic direction
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When an eruption occurs, the ions of iron will do what?
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point North at the time of solidification
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What do the ions in iron aligning themselves to magnetic north as the crystals grow help geologists do?
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determine magnetic reversals
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how many magnetic reversals have happened over the last 76 million years?
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170
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Short term magnetic reversals happen how often?
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every thousand of years
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Epochs, longer term magnetic reversals happen how often?
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every few million years
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_____________ is an observed result of something else.
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continental drift
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___________ is a global process driven by mantle convection.
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plate tectonics
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_____________ is a casual mechanism (what actually makes plate tectonics move) driven by radiation.
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mantle convection
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What serves as the heat source for the mantle?
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radioactive stuff
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Past climates, fossils, structural continuity, apparent polar wandering, and fit of the continents are all evidence of what?
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continental drift
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______________ allows us to see that mountain belts link up to other features....so they used to be connected.
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structural continuity
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What evoked the continental drift theory?
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Past climates: the fact that India was under ice in the Northern Hemisphere.
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What made geologists disagree that the entire earth was frozen 250 million years ago?
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Coal from rain forests
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Each continent has its own what?
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polar wandering curve
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___________ makes up more than 80% of the earth's volume and two-thirds of its mass.
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Mantle
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The mantel is made up of three parts...what are they?
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upper mantle, the astehnosphere, and the lower mantle
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The departure from expected force of gravity is what?
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a gravity anomaly
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The unloading of the crust causes it to respond by rising upward until equilibrium is again attained. This is called what?
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isostatic rebound
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Morphology of the ocean floor, age of the ocean basins, and magnetic striping are all evidence of what?
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plate tectonics
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Technology gave us what about the ocean?
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shape of the sea floor and composition of the ocean crust
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What allows us to get the depth of the ocean sea floor?
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sonar (sound waves)
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What percentage of the earth's surface is covered by oceans and seas?
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71%
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At _________________ the sea levels rising and falling will record a history in the sediments on the shorelines.
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passive continental margins
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At _______________ there is mostly a mix of shallow marine deposits and no earthquake or volcano activity.
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passive continental margins
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___________ active continental margin.
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Pacific
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__________ passive continental margin.
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Atlantic
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______________ develops at the leading edge of a continental plate where oceanic lithosphere is subducted.
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active continental margin
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In a passive continental margin the continental slope has an enormous what?
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submarine fan
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________________ is sediment delivered after an earthquake at the rate of volcanic ash. It rolls down the slope and deposits on the submarine fan.
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turbidity flow
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______________ margins are associated with volcanic and earthquake activity.
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active continental margins
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Active continental margins have _________.
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trenches
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Passive continental margins have _________.
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slopes
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These characteristics are for what kind of continental margin?
Negative gravity anomaly Benioff seismic zone 6000 km long 100 km wide 8-11 km deep |
active continental margin
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In a leading and trailing margin, what is happening?
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the pacific active is leading (tractor)
the atlantic passive is trailing (trailer) |
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_________ is a system of mostly submarine mountainous topography.
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mid oceanic ridge
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What are oceanic ridges mostly compose of?
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basalt and gabbro
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Where does the MOR rise above land at?
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Iceland
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______________ are a place where new oceanic crust is generated and plates diverge.
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oceanic ridge
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The mid oceanic ridge system is how tall?
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2-3 km
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The mid oceanic ridge system is how deep?
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2 km
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The mid oceanic ridge system is how long?
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65,000 km
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The mid oceanic ridge's earthquake activity is shallow or deep?
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shallow
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Humans are dependent on photosynthesis. Oceanic ecosystems are dependent on what?
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chemosynthesis
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Pillow basalts and black smokers/vents are characteristics of what?
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mid oceanic ridge systems
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_________ is building basalt and pushing the valley further out.
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mid oceanic ridges
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Older rocks are located where at the oceanic ridge?
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further out
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To figure out __________ we need to know the rate of reversal and the rate at which the crust is spreading and producing magma.
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magnetic striping
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There are three types of plate boundary actions. What are they/
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stretch (tension)
squeeze (compression) slide (shear) |
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Where is new crust made?
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oceanic rifts and MOR
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Where is there neither destroying of the crust nor making of the crust?
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transform margins
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What is happening at:
Ocean/Ocean Collisions Ocean/Continent Collisions and Continent/Continent Collisions |
Destroying of the crust
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What melts before magnesium and iron?
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silica
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After subduction, rising, weathering, and subduction again, what are the sediments?
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more silica rich
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In ______________________ the makeup is mostly silica rich, over time the chemistry makeup will move down Bowen's reaction series.
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island arc system
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The earth is _________ crust at oceanic ridges.
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making
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The earth is ________ crust at trenches.
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destroying
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___________ is low pressure/high temperature.
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hornfels
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_____________ is high pressure/low temperature
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bludschist
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___________ is high pressure/high temperature.
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eclogite
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__________ is high pressure/high temperature.
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granulite
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_______ is medium conditions.
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amphibolite
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_______ is low conditions.
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greenschist
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What sea is making a new ocean right now?
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Red Sea
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The deeper into the earth you go, the _______ the temperature and pressure.
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Higher
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India is ______________ Southern Asia.
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subducting under
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Because a continent is less dense and wants to bounce back up like a Styrofoam board at the bottom of a pool, you can't ________ it.
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subduct
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Southern Asia is eroding faster or slower after the continent continent collision?
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faster
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What forms at continent/continent collisions?
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migmatite
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The pressure and temperature are _________ at continent/continent collisions.
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high
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why is southern asia eroding faster?
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because India is trying to rise
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At spreading centers, things are ripped apart, creating what?
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rift valleys
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As things are ripped apart in spreading centers, the crust does what?
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thins
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The aesthenosphere conditions are weak and are almost a liquid, but remains a solid. As pressure releases, the aesthenosphere becomes what?
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a liquid
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As the aesthenosphere becomes a liquid at a spreading center, what happens?
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it rises and forms volcanoes
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What do spreading centers eventually lead to?
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an ocean
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What do spreading centers cause?
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passive continental trailing margins
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Rift means what?
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pulling apart
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The North Atlantic plate is moving _______ the the South Atlantic plate.
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slower
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______________ change one type of motion between plates into another type of motion.
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transform faults
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At a ________________ an interior mountain belt is formed consisting of deformed sediments and sedimentary rocks, igneous intrusions, metamorphic rocks, and fragments of ocean crust.
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continental/continental plate boundary
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Spreading centers are also called what?
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divergent plant boundaries
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______ mostly occur along fractures in the seafloor where plates slide laterally past each other roughly parallel to the direction of plate movement.
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transform faults
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________________ have movement in 3 different directions at one time.
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transform faults
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__________ have differential spreading rates because we live on a curved surface.
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transform faults
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Name a well known transform fault.
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San Andreas
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What drives plate tectonics?
What drives the mantle? |
the mantle
radioactivity |
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Name a well known transform fault.
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San Andreas
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What drives plate tectonics?
What drives the mantle? |
the mantle
radioactivity |
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Anticline and synclines are exposed in areas of what?
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deep erosion
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Anticlines and synclines are easily distinguished by their ________ and ___________ and the relative ages of the folded layers.
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strike and slip
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In a ____________ fold, both limbs dip in the same direction because one fold limb has been rotated more than 90 degrees from its original position so that it is now upside down.
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overturned
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In __________ folds, the axial plane is horizontal.
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recumbent
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________ and _________ folds formed by compression or convergent plate boundaries.
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recumbent and overturned
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