The single most important agent sculpting the Earths land surface
running water
Lowering a streams base level will cause the stream to
downcut
along a stream meander, the maximun velocity of water occurs
near the outer bank of the meander
a typical profile of a stream exhibits a constantly ______ gradient from the head to the mouth
decreasing
the flat portion of a valley floor adjacent to a stream channel
floodplain
which type of drainage pattern will most likely develop where the underlying material is relatively uniform
dendritic
ice sheets and glaciers represent ___% of the total volume of freshwater
85
the function of artificial levees built along a river is to control
flooding
plant release water into the atmosphere through a process called
transpiration
Occasionally depostion causes the main channel of a stream to divide into several smaller channels called
distributaries
the average annual precipitation worldwide must equal the quanity of water
evaporated
during periods when rain does not fall, rivers are sustained by
groundwater
which on of the following would least likely be found in a wide valley
rapids
along straight stretches the highest velocities of water are near the ___ of the channel, just below the surface
center
the combined effects of ____ and running water produce stream valleys
mass wasting
which one of the following is a measure of material's ability to transmit water through interconnected pore spaces
permeability
the capacity of a stream is directly related to its
discharge
drawdown of a well creates a roughly conical lowering of the water table called the cone of
depression
in a typical stream, where gradient is steep, discharge is
small
most natural water contains the weak acid, ____ acid, which makes it possible for groundwater to dissolve limestone and form cavers
carbonic
the area above the water table where soil is not saturated is called the zone of
aeration
most streams carry the largest part of their load
in suspension
the great majority of hot springs and geysers in the US are found in the
West
Whenever the water table intersects the ground surface, a natural flow of water called a ___ results
spring
a broad ramplike surface of stratified drift built adjacent to the downstream edge of most end moraines
outwash plain
icebergs are produced when large pieces of ice break off from the front of a glacier during
calving
which type of dune will form at a right angle to the prevailing wind when there is abundant sand, little or no vegetation and a constant wind direction
transverse dune
most of the major glacial episodes during the ice age occurred during a division of the geologic time scale
pleistocene epoch
the two major ways that glaciers erode land are abrasion and
plucking
which one of the following is NOT an effect that pleistocene glaciers had upon the landscape
mass extinctions
a thick ice mass that forms over the land from the accumulation compaction and recrystallization of snow
glacier
the ____ drainage of arid regions is characterized by intermittent streams that do n ot flow out of the desert to the ocean
interior
the all-embracing term for sediments of glacuial origin
glacial drift
the end moraine that marks the farthest advance of a glacier is called
terminal moraine
cracks that form in the zone of fracture of a glacier
crevasses
desert streams that carry water only in response to specific episodes of rainfall are said to be
ephemeral
sinous ridges composed of sand and gravel deposited by streams flowing in tunnesl beneath glacial ice
eskers
materials that have been deposited directly by a glacier are called
till
valleys that are left standing high above the main trough of a receding valley glacier are termed
hanging valleys
the thickest and most extensive loess deposits occur in western and northern
China
glacial troughs that have become deep steep-sided inlets of the sea are called
fiords
moraines that form when two valley glaciers coalesce to form a single ice stream are termed
medial moraines
boulders found in glaciers till or lying free on the surface are called glacial
erratics
which on of the following is NOT a feature associated with valley glaciers
arroyo
dry flat lake beds located in the center of basins in arid areas are called
playas
the most noticeable result of deflation in some places are shallow depressions called
blowouts
evidence indicates that in addition to the pleistocene epoch, there were at least ___ earlier periods of glacial activity
three
the leeward slope of a dune is called the
slip face
which one of the following states is included in the Basin and Range region
nevada
it is estimated that over ______ earthquakes that are strong enough to be felt occur worldwide annually
30,000
the location on the surface directly above the earthquake focus is called the
epicenter
the cool rigid layer of earth that includes the entire crust as well as the uppermost mantle is called the
lithosphere
underground storage tanks rising to the surface as the result of an earthquake is evidence of
liquefaction
which earthquake body wave has the greatest velocity
p wave
the belt from about 105-140 degrees away from an earthquake where no P waves are recorded is known as the
shadow zone
the study of earthquakes is called
seismology
which one of the following regions has the greates amount of seismic activity
the circum-pacific belt
the difference in _____ of Pand S waves provides a method for determining the epicenter of an earthquake
velocities
the source of an earthquake is called the
focus
long-range earthquake forecasts are based on the premise that earthquakes are
repetitive
the epicenter of an earthquake is located using the distances from a minimum of __ seismic stations
three
which of the earthquake body waves cannot be transmitted through fluids
S waves
dense rocks like _____ are thought to make up the mantle and provide the lava for oceanic eruptions
peridotite
in areas where unconsolidated materials are saturated with water, earthquakes can turn stable soil into a fluid during a phenomenon called
liquefaction
the adjustments of materials that follow a major earthquake often generate smaller earthquakes called
aftershocks
an earthquake with a magnitude of 6.5 releases __ times more energy than one with a magnitude of 5.5
30
earthquake epicenters are most closely correlated with
plate boundaries
the amount of damage caused by an earthquake at a specific location is used to determine the intensity of an earthquake in the
modified mercalli scale
the greatest concentration of metals occure in earth's
core
most of earth's seismic activity, volcanism, and mountain building occur along
plate boundaries
the apparent movement of earth
(blank)
the type of plate boundary where plates move together, causing one of the slabs of lithosphere to be consumed into the mantle as it descends beneath an overriding plate, is called
convergent boundary
typical rates of seafloor spreading average around __ centimeters per year
5
the name given by Wegener to the supercontinent he believed existed prior to the current continents was
pangoea
magnetic minerals lose their magnitism when heated above a certain temperature, called the
curie point
the best approximation of the true outer boundary of the continents is the seaward edfe of the
continental shelf
the ateutian, mariana, and tonga islands are examples
volcanic island arcs
beneath earth's lithosphere, the hotter, weaker zone known as the ______ allows for motion of earht
asthenosphere
one of the main objections to wegener's hypothesis was his inability to provide an acceptable _____ for contiental drift
mechinism
the spreading rate for the mid-atlantic ridge is ___ than the rate for most of the east pacific rise
less
earth's rigid outer shell is called
lithosphere
most deep-focus earthquakes occur in association with
open trenches
the theory of plate tectonics holds the earth
(blank)
most deep-focus earthquakes occur in association with
open trenches
the theory of plate tectonics holds the earth's rigid outer shell consists of ___ major plates
seven
the age of the deepest sediment in an ocean basin _____ with increasing distance from the oceanic basin
increases
during oceanic-continental convergence, as the oceanic plate slides beneath the overriding plate, a _______ is often produced adjacent to the zone of subduction
deap-ocean trench
the chain of volcanic structures extending from the hawaiian islands to midway island and the continuing northward towaed the aleutian trench has formed over a _____ as the pacific plate
Science Vocab 147928
