Earth Science Topic 12
Terms
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- is the outer core solid liquid or gas?
- liquid
- epicenter
- spot on the surface above the point in the ground of the earthquake
- focus
- the point under teh ground where the earthquake occurs
- crust
- upper portion of the lithosphere
- orginial horizontality
- sedimentary rocks and some extrusive igneous rocks form in horizontal layers parallel to earths surface
- fault
- crack in a mass of rock along which there has been displacement, shifting, or movement of the rock layers on each side of the crack
- what principle supports the conclusion that layers have undergone extensive movement since deposition?
- deposited in horizontal layers
- what do tilted rock layers suggest?
- crustal movement occurred sometime after the sediments were deposited
- land uplift
- land has been raised up to its present position
- what does it suggest when marine rocks are found in sedimentary rock hundreds or thousands of meters above sea level?
- the land has been uplifted
- what are most earthquakes caused by?
- movement along faults
- seismic waves
- earthquake waves that give off potential energy
- seismogaph
- instrument that shows how earth sjhakes from seismic waves
- seismogram
- recording of the amplitudes of the wave that represent earths shakings
- what are the 3 categories of seismic waves
- p-waves, s-waves, and surface waves
- what way do the particles that p-waves travel through vibrate?
- in the direction of the waves
- what is slower s or p waves
- s-waves
- what way do the particles vibrate when s waves travel through them
- at right angles
- what reaches a seismograph first?
- pwaves
- how does velocity of waves change?
- more dense, the greater velocity of waves
- what can pwaves pass through
- solids, liquids, and gases
- what can swaves pass through
- only solids
- time interval vs. distance from epicenter
- bigger the time interval, the farther the distance to the epicenter
- damage vs. closeness to epicenter
- the closer to the epicenter, the greater the damage
- how can a reasonable earthquake prediciton be made?
- by knowing the earthquakes history of a specific zone
- 5 waays to prepare for earthquakes
-
1. radios
2. fragile tems on floor
3. keep cabinets locked
4. extra food, batteries
5. practice drills - tsunami
- large wavelength oceanwave produced by disruption of the ocean floor
- what can the disruption be from?
- faulting associated with an earthquake, colvani eruptions, or rapid landslide type of mass movement
- volcano
- mountain composed of extrusive igneous rocks
- how can u predict a volcano eruption?
- satellites measure infrared energy froom the upper atmosphere and report on the increasing heat from rising magma. when the magma rises, a chicken is coming
- ring of fire
- regions surrounding the pacific ocean that contain a majority of these related events and features: earthquakes, uplifting, sinking, volcanic eruptions; ocean trenches, island arches, mid-oceans irdges
- mid-ocean ridge
- moutain ranges in ocean areas
- where do most earthquakes originate?
- aloing specific belts within the crust
- where are volcanoes mainly located?
- zones of crustal activity
- where is teh shadow zone from?>
- 102-143 debgrees
- in which parts of earths interior would melted or partially melted material be found?
- asthenosphere and outer core
- the composition of some meteorites supports the inference that earths core is composed of
- iron and nickel
- what is the oceanic crust made of?
- mostly basalt
- what is the continental crust mostly made of?
- granite
- how does thickness and density of the continental crust compare to that of the oceanic crust?
- the continental crust is thicker and less dense than the oceanic crust
- what is the san andreas fault system ?
- an example of a transform plate boundary between north american and pacific plates
- divergent boundary
- plates move apart and magma rises from below to fill the separation, resulting in igneous intrustions and extrusions.
- convergent plate boundary
- when two plates collide
- 3 types of convergent boundaries
-
1. both plates w/ oceanic crust on top
2. both plates w/ continental crust on top
3. one with cont. one with oc. - transform plate boundary
- when two plates collide by sliding past each other
- what is the most accepted theory of how plates move?
- mantle convection currents drag or push the plates apart at places hwere plates diverge
- according to the theory of plate tectonics, the distance between two continents on opposide sides of a mid-oceanic ridge will generally
- increase
- what feature is commonly formed at a plate boundary where oceanic crust converges with continental crust?
- an oceanic trench
- what are two pieces of evidence that prove africa and south america were one part of the same large continent?
-
1. matched up minerals
2. matched up fossils - evidence of subduction exists at the boundary between the __plates
- indian, australian, and antarctic plates
- what do igenous materials found along mid-ocean ridges that contain magnetic particles show?
- the reversal of magnectic orientation
- what is this evidence of?
- that earths magnetic poles have exchanged their positions