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instrument that records seismic activity
Moment magnitue scale
earthquake scale
more accurately indicates energy release during large quakes
measures seismographic data in a diff way and can be modified by feild observations
most commonly used these days
some large quakes of the past have been reduced
super continent proposed by Alfred Wegner in 1915
amount of shaking
oceanic continental boundaries
type of convergent boundary
create a subduction zone, trench, and a volcanic arc
ex. the Andes Mnts
Mercalli Scale
earthquake scale used to indicate a quake''s intensity based on actual effects
strike-slip fault
type of transform boundary
a fault w/ lateral movement rather than vertical movement
Fault Block mnts
made primarily of horsts and grabens
ex. basin and range area of Utah, CA, and Nevada
frozen layers of soil
some soil can thaw and flow slowly over the underlying frozen soil
Bed load
one way a stream can move materials
sediments rolled along the bottom of a stream
Suspended Load
One way a stream can move materials
Particulate sediments being carried by currents
Most sediment carried in streams is in 
alluvium fan
sediments deposited by a stream
Volcanic peaks that rise from the bottom
Scattered about the Ocean Basin Floor theres numerous of these
These can be produced by hot spots or tectonic boundaries
Periodic changes in local sea level produces by the gravitational pull of the moon and the sun
Beach nourishment
Sediment is collected in one place and moved to another
Elongated sand bodies that project from land
Absolute dating
give age as a number
Neap tides
Tides w/ the least tidal range
Occur when sun and moon are perpendicular to each other
Principle of Original Horizontality
Key principle of relative dating
Sediments are generally deposited in horizontal layers.  Those that arent horizontal have been deformed
Any channelized flow of a liquid
They can move in 3 ways:
Dissolved load
Suspened load
Bed load
Dissolved Load
Way a stream can move materials
Dissolved solids carried in a stream
Relative dating
shows whats younger/older w/o a number
Principle of Fossil Succession
principle of relative dating
Fossil organisms succeed each other in a difinite order, so rocks taht contain them can also be arranged in order
Spring Tides
Tides w/ the greatest tidal range (difference between high and low)
When the sun and moon are aligned (during full and new moon phases tidal effect strengthens)
Semidiumal Tides
2 high and 2 low tides each day
Most areas have this
Surface currents
Driven by winds that blow across the oceans
Mesozoic Era
Part of Phanerozoic Eon
age of reptiles/dinos
astroid hit Mexico and dinos went extinct 66 million yrs ago.  mammals and reptiles survived
matching rocks in diff locations to build a geologic history
type of marine sediment that comes from land
Phanerozoic Eon
An explosion of fossils at about 540 million yrs ago
Divided into eras and periods cenozoic, mesozoic, and paleozoic
Principle of Cross-cutting relations
principle of relative dating
faults/intrustions are younger than rocks theyre found in
cenozoic era
part of Phanerozoic eon
mammals became dominant group
first human ancestors finally showed up 2 mill yrs ago (64 yrs after dinos went extinct!)
Paleozoic Era
End of = mass distiction 80-95% of marine life
Many invertebrates developed the ability to make parts.  Lots of fossils appear on rock record
First land plants appear, great swamps develop, huge coal deposits
Age of invertebrates, fishes, and amphibians
Transition to land made by waterproof skin and eggs
A sand body that connects an island to the shore
Found along the margins of much of the Ocean Basin Floor too, w/ the deepest being the
Human built structure
parallel walls on either side of a harbor or bay that keep the entrance open
Thermohaline Circulation
Circulation driven by differences in temp and salinity
Near the poles, water gets very cold and saltier when ice forms in it.  So it gets more dense and sinks
Produces deep water currents that move along ocean floors.
Baymouth Bars
spits that close off a bay/harbor
Precambrian Eon
Earth is about 4.6 billion yrs old
88% of that time is called the  
Fossils are microbes and a few soft-bodied animals. lots of organisms jsut hard to preserve as fossils
A structure is dissolved away, then the void is filled w/ mineral deposits
Uncommon types: bugs in amber, carbonized leaves, footprints/tracks, burrows, gastroliths, and caprolites
Seamounts where the tops have been weathered away, leaving them flat on top
When tiny voids in bones and such are filled by mineral deposits
Radiocarbon Dating
Absolute dating
Using carbon 14 to date things from the recent prehistoric past (thing less than 50,000 yrs old)
Longshore currents
assoc with beach drift
Sediments are moved down the shore underwater
Ocean Ridges
typically in the middle of ocean basins
Mabye as tall as many terrestrial mnts
organic solid parts are dissolved away and replaced by mineral deposits
Ocean currents
Masses of water taht move from one place to another
can be at the surface or in deep water and can move laterally and/ or vertically
Abyssal plain
Most of the Ocean Basin floor is a flat featureless expanse called 
These are the flattest parts of the earth and are covered by a blanket of very fine sediments from land and dead plankton
Continental Shelf
Part of a passive margin (cont margin)
A gently sloping area, which is simply the part of a continent thats under water
Walls built perpendicular from land out into the water to stop beach lift
Human built
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