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| 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 |
hot spot |
