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81 Cards in this Set
- Front
- Back
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What are the 3 ways the river systems modify land surface? |
-Erosion -Transportation -Deposition |
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What are the four stream network patters? |
-dendritic -radial -trellis -rectangular |
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What is a dendritic stream patterns? |
treelike, tributaries meet a main stream at acute angles. Normally, associated with uniform bedrock area and flat land, such as plain, plateau regions. |
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What is a radial stream pattern? |
drainage diverges away from a central high area -associated landform: dome, volcanic cones, and glacial horns |
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What is a trellis stream pattern? |
parallel streams joined with short tributaries at nearly 90 degrees. -folded mountain, coastal plains |
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What is a rectangular or other structure controlled patterns? |
streams forms rectangular fissures or joints |
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What are the two ways that you can classify streams? |
-size & shape -permanence of flow |
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What are the 3 shapes streams can take |
-straight (youngest) -meandering -braided |
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What are the 4 classifications under permanence of flow? |
-perennial -intermittent -ephemeral -exotic |
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What is stream discharge? |
the volume of water passing a certain point per unit of time |
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What is stream velocity? |
depends on stream discharge, shape and roughness, and especially the stream gradient |
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What is stream gradient? |
vertical elevation drop over a given horizontal flowing distance |
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What is a bedrock? |
the rock's resistance affects stream velocity and channel shapes |
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What is base level? |
the lowest level to which a stream can erode its channel, the elevation at the stream's mouth |
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What are different types of erosion? |
-abrasion -corrosion -downcutting -lateral erosion -headward erosion |
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What are knickpoints? |
location where gradient is high and water flows faster |
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What is a graded stream? |
stream with a smooth concave longitudinal profile, has achieved a dynamic equilibrium between its velocity and load (erodes down knickpoints) |
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What are the 3 types of stream transportation? |
-dissolved load -suspended load -bed load |
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What is a dissolved load? |
chemical matter is dissolved in the water |
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What is a suspended load? |
the largest amount of material transported by a stream |
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What is a bed load? |
Moving along the stream bottom by saltation and traction |
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What is stream capacity? |
the maximum load a stream can transport -determined by the stream's discharge |
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What is stream competency? |
indicates the maximum particle size a stream can transport -determined by the stream's velocity |
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When do streams deposit? |
-whenever it slows down -gradient decreases -discharge decreases -velocity decreases -shape changes |
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What are stream depositional features? |
-floodplain -levee -point bars -deltas -alluvial fans -island bars |
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How does a stream evolve/ mature? |
-climate changes -tectonic changes -stream rejuvenation: deepens and meanders in shape -land use -stream management |
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What is a shoreline? |
it is a dynamic interface among air, land, and the ocean -it is constantly being modified
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What are tides? |
the oscillation of water in a predictable fashion due to the gravitational pull of the moon and of the sun |
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What are waves? |
the rising and falling motions of ocean waters caused mainly by surface winds, and submarine activities -most important agent of shaping coastlines |
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Wavelength |
between two adjacent crests or troughs |
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Wave height |
vertical distance between trough and crest |
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Tsunami |
strong wave triggered by earthquake |
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Deep water waves? |
symmetrical with no apparent forward motion |
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shallow water waves |
when water depth <1/2 wavelength -wave surf forward |
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Wave breaker |
when water depth < 1/20 wavelength -wave breaks |
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What is wave translation |
as waves approach shallow shore wavelength decreases and wave height increases |
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What is wave refraction? |
as waves approach irregular shoreline, wave appear changing direction or bending -most converge toward headlands and diffuse away from bays |
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What is a current? |
horizontal movement of a large volume of water -caused by temp, salinity, and oblique waves |
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What are the different types of currents? |
-surface -deep water -longshore current -rip currents |
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What are some coastal depositional features? |
-beach -spits -baymouth bars -barrier islands -tombolo -tidal delta -lagoon |
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What are some influencing factors of shoreline erosion? |
-proximity to sediment-laden rivers -degree of tectonic activity -topography and composition of the land -prevailing wind and weather -configuration of the coastline |
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What are the 3 responses to erosion problems |
-building structures -beach nourishment -abandonment and relocation of buildings away from the beach |
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What happens as sea level rises and drops? |
rises: coast of submergence drops: coast of emergence |
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What is a primary coast? |
shaped dominantly by terrestrial processes |
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What is a secondary coast? |
shaped dominantly by marine processes |
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What is a fjord coast? |
A long, narrow, deep inlet from the sea between steep slopes of a mountainous coast. Fjords usually occur where ocean water flows into valleys formed near the coast by glaciers. |
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What is a coral reef |
cluster of polyps with hard external skeleton |
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Where can you typically find a coral reef? |
clear, warm, shallow sea over continental shelf |
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What are the different types of reefs? |
-fringe reef -barrier reef -atoll -platform |
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What are the 2 types of glaciers |
Valley (alpine) continental/ ice sheets |
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Zone of accumulation |
net gain of ice |
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zone of ablation |
ice loss by melting, evaporating, and calving along its edge |
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snowline |
the lowest topographic limits to sustain a year-round snow cover, the boundary between the zone of accumulation and ablation |
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Real movement of glaciers? |
from zone of accumulation to the zone of ablation basal slip: movement as whole along the bottom differential: central part moves faster and steep slope moves faster creating crevasses |
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Apparent movement |
advancement and retreat of its terminus due to the change in snowline |
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When was the last ice age (Pleistocene) |
about 10,000 years ago -covered30% of landmasses in ice |
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Erosion through plucking |
ice wedging, then the loosened bedrock frozen to the bottom of a moving glacier |
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Erosion through abrasion |
the rasping action of moving ice and its rock loads against the bedrock and forming polished glaciated hills, striations, and grooves |
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Alpine Glaciation erosional and depositional features |
-erosion: cirque, tarn, horn, arête, U-shaped trough -deposition: erratic, moraines, outwash plain |
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What is a moraine? |
layers or ridges of till left behind by a retreating glacier |
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What is an erratic? |
larger boulder that is not from the nearby bedrock, but transported by glacier from far away |
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What is outwash |
deposits from glacial meltwater |
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Continental erosional and depositional features |
erosion: tends to level off the land surface deposition: erratic, moraines, drumlins, eskers, outwash plains, and kettle lakes |
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What is an earthquake? |
is the vibration of earth, produced by the rapid release of energy |
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What is the focus? |
a subsurface place where earthquake occurred/started, the initial site of rock failure |
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What is an epicenter? |
the surface location directly above the focus |
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What are the cause of earthquakes |
faulting of rocks and releases strain energy |
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What Is the Elastic Rebound Theory? |
as internal tectonic forces act on rocks, rock will bend and then fail (break) when the strain energy exceeds the strength of the rocks |
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P-waves |
compression, primary, or push-pull waves -vibration is parallel to the direction in which the wave is moving -travels fastest speed and transmits through all media |
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S-waves |
shear or secondary waves -movement is perpendicular to the direction in which the wave is moving -travels only through solid material -slower than P waves |
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Surface Waves |
travels along earth's surface -movement is perpendicular to the direction of the wave -causes great ground vibration and travels the longest distance in the slowest speed -causes the most damage on the surface |
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Seismograph |
-time lapse between seismic P-S waves -distance to the epicenter -amplitude of ground movement -earthquake magnitude -time when the earthquake will occur |
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how to locate epicenter |
at least three different seismograms needed to pinpoint |
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Richter Scale |
measures the magnitude of ground motions and the amount of energy released by an earthquake |
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Intensity scale |
based on ground survey of the damages to surface structures -ranges from 1-7 |
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What are the factors of the intensity scale? |
-magnitude of quake -types of rock and rock structure -distance from epicenter -human awareness and preparation |
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What are some earthquake hazards? |
-infrastructure and loss of lives -ground shaking -seiches -Tsunami -liquefaction -landslide, broken dam, fire, etc. |
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Earthquake predictions |
no reliable method for short range predictions -look at precursors like uplift, tilt, foreshocks, abnormal animal behavior, etc.
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plate tectonics and earthquakes |
earthquakes are mostly distributed along plate boundaries |
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What is the most important erosion agent? |
WATER |
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Erosional landforms of fluvial, coastal, and glacial processes. |
fluvial- meandering cutback, bluff, terraces, knickpoint coastal- sea arch, cliff, sea stack, inlets, marine terraces Glacial- horn, arête, cirque, hanging and U- shaped valley |
