theme two Flashcards
volcano def
cone shaped mountained formed by eruptions of lava at the surface of the earth
crater def
a depression on the surface of a volcano, formed by volcanic activity, often circular in shape with deep sides.
vent def
the natural pipe or fissure that links the magma chamber to the crater or opening on the earths surface through which lava, ash and gases flow.
lava def
magma that has escaped from beneath the earth’s crust and has flowed onto the surface.
tectonic plates def
huge pieces of the earths crust that float and move on top of the much denser mantle below them
constructive/divergent plate boundary def
where two plates move apart, allowing magma to come to the surface as lava
magma def
molten rock found beneath the earths crust
magma chamber def
a large natural underground chamber of magma found within the surface of the earth beneath a volcano.
destructive/convergent plate boundary def
where two plates move towards each other
subduction def
when one plate sinks below another
hot spot def
a central part of the earths crust where plumes of magma rise to the earths surface
how can magma leave a volcano on to the earths crust
lava
volcanic bombs
very fine ash
what can volcanic eruptions be accompanied by
pyroclastic flows
lahars
earthquakes
composite/strato volcanoes
these are made from alternating layers of lava and ash as both come out of the vent during an eruption.
where do composite/strato volcanoes form
on destructive plate boundaries
shield volcanoes
these are made from lava. they from large volcanoes with gently sloping sides, sometimes hundreds of kilometres across before cooling and solidfying
where do shield volcanoes form
on a constructive plate boundary
dome volcanoes
these are also made from lava but the lava is acid and thicker and cools quicker. it does not flow very far before becoming solid and are steep sided and high.
active volcano
one that has recently erupted and is likely to again.
domant volcano
one that has erupted in the last 2000 years and may erupt again. hard to predict.
extinct volcano
long since finished erupting and has cooled down
earthquake def
a sudden and often violent shift in the rocks forming the earth’s crust, which is felt at the surface.
fault line def
a fracture or break in the earths surface along which rocks have moved alongside each other
focus def
the location of the actual source of an earthquake below the ground surface; also called the origin
conservative platae boundary def
where two plates are sliding alongside each other
epicentre def
location on the surface of the earth above the focus or origin of the earthquake
tsunami def
powerful, devastating waves at the coast caused by an undersea earthquake or volcanic eruption that displaces the water lying above it
seismometer def
an instrument that meaures movement of the ground, including the seismic waves generated by earthquakes and volcanic eruptions
seismic waves
waves of energy that travel through the earths layers as a result of earthquakes, volcanic eruptions, magma movements and large landslides
moment magnitude scale and richter scale def
numerical scales showing the size or magnitude of an earthwuake based on readings from a seisometer
mercalli scale def
a scale showing the effect of an earthwuake on the earths surface
aftershock def
a smaller earthquake following after the main earthquake
fold mountains def
a long, high mountain range formed by uplifting and folding of sediments
convection currents def
differences in temperature of material beneath the plates of the earth’s crust leads to the creation of currents to transfer the heat. these currents move the plants above them.
subduction zone def
the zone where one tectonic plate sinks under another
island arc def
a chain of volcaniv islands located above a subduction zone at a tectonic plate boundary
tephra def
rock fragments and particles ejected by a volcanic eruption
fumarole def
an opening in or near a volcano, through which gases, such as sulphur dioxide, are emitted
impacts of earthquakes and volcanoes on people
loss of life cutting of basic necessitites collapse of bildings infrastructure damage loss of crops fish can be killed spread of disease loss of jobs and businesses higher insurance premiums
primary effects
direct result of the earthquake or volcanic eruption
secondary effect
result of primary effects
what does the amount of damage caused by earthquakes depend on
strength depth distance from epicentre geology building construction and design space between buildings population density time of day secondary hazards like landslides contamination
opportunites granted by volcanoes
volcanic soils often fertile
geothermal power
raw materials / resources
attract tourists
how to reduce impact of volcanoes and earthquakes
improved technology
mapping high risk areas
improvind building design
ensuring emergency drills are in place
how can scientists predict volcanic eruptions
seismometers tilt meters thermometers gas sensors satellites
swash def
the movement of a sea wave up a beach after the breaking of a wave
backwash def
the movement of a sea wave down the beach after the breaking of a wave
hydraulic action
the weight and force of a wave crashing against a cliff removes particles of rockss from the cliff. also includes the process where air is trapped by a wave in a cliff and the enormous hydraulic pressure this creates opens up the clfif further.
abrasion
where rocks and sand are picekd up by a wave and thrown against the cliff
solution
some minerals are put into solution by weak acids found in seawater
attrition
rocks on the beach are rolled up and down the beach by swash and backwash. as this happens they collide with each other and become smaller and rounder as a result
longshore drift def
the movement of material along a beach transported by wave action
spits def
ridges of sand or shingle attached to the land but ending in open sea
bars def
ridges of sand or shingle acrss the entrance of a bay or river mouth
tombolos def
spits connecting an island to the mainland
groynes def
wooden, stone or concrete barriers built perpendicular to the coast in order to break waves and reduce the movement of sediment along the beach
constructive wave action
swash stronger than backwash so more sand and shingle will travel up the beach
destructive wave action
swash weaker than backwash so more sand and shingle will be moved down offshore
salt marsh def
an area of mudflats formed when sediment is deposited in the low wave energy area behind a spit
cliff notch def
a small overhang formed at the base of a cliff by wave action
wave cut platform def
a wide, flat area of rock at the bottom of cliffs seen at low tide
headlands def
areas ofmore resistant rock jutting out from the coast into the sea
cave def
a hollow at the base of a cliff which has been eroded by rocks
arch def
a rock bridge formed at a headland that has been partly broken through by the sea
stack def
an isolated column of rock at the end of a headland formed after a stack has collapsed
bay def
a broad coastal inlet, often curved and with a beach, between two headlands
what will happen if the coastline alternates between soft and hard rock
differntial erosion will take place resulting in a disconcordant coastline
wherer do salt marshes form
sheltered bays and estuaries in the protected area behind a spit or tombolo
coral reef def
a ridge of rock near the surface of the sea, formed by frowth and deposit of coral
types of coral reef
barrier
fringe
atoll
conditions for coral reefs to form
temp has to be 23-25 degrees depth of water had to be less than 25cm water has be clear for lots of sunlight low salinaty low sediment high energy wave action for freshly oxygenated water exposure to air
where are mangerove swamps found
along coastliens between 30 north and 30 south of the equator.
magrove swamps def
tidal swamps that are dominated by mangroves (shrubs or small trees with numerous tangled roots that grow above ground
adaptations of mangroves
low oxygen conditions low salt intake in tree low water loss aerial roots to absorb nutrients the seeds float
roles of mangroves
coastal protection
breeding ground
source of food, medicine and raw materials
managing impacts of coastal erosion
sea walls
revetment
gabions
rock armour
groynes
beach nourishment
assessments on how to defend a coast:
cost-benefit analysis
environmental impact assements
shoreline management plan
tropical storm def
areas of very low pressure in low latitudes, with strong winds and heavy rains
ICZM def
integrated coastal zone management
the management of the coast using an integraed approach, taking into account all aspects of the coastal zone, including geographical and political boundaries
littoral cell def
a length/section of the coast that is isolated from adjacent sections of coast and has its own sources
weather def
the state of the atmosphere at any paticular moment in time
climate def
a description of the averages and extremes of weather variables of an area over an extended period of time
stevenson screen def
a container in which weather/meteorological instruments are placed
isohyet def
a line on a map joining places of equal rainfall
how is weather data collected
stevenson screen rain gauge maximum minimum thermometer wet and dry bulb thermometer barometer anemometer wind vanes cloud cover sunshine recorder
diurnal range def
the daily range of temperature
relative humidity def
the amount of water vapour (moisture) in the air, expressed as a percentage of the maximum amount of water vapour that the air could hold at a given time
stevenson screen
box that contains weather/meteological for protection
rain guages
many characteristics for an accurate reading
maximum and minimum thermometers
measures diurnal range
wet and dry thermometers
measures relative humidity by measuring the temperature of the air and the temperature of the air if there was 100% humididty
sunshine recorder
measures the length of time that the sun has shone during the day in between periods of cloud cover, fog or when the sky has been obscured by smoke or some other form of pollution
barometer
measures atmospheric pressure in millibars (mb)
anemometers
measure the speed of wind
wind vanes
indicate wind direction
cloud cover
the amount of cloud covering the sky is measured in oktas
characteristics of an equitorial climate
low range of monthly mean temps constant high temp high rainfall high humidity high levels of soil moisture
equitorial climatae def
the constantly hot and cold wet climate of regions near the equator
insolation def
a measure of the amount of solar energy received per square centimetre per minute at the earths surface
prevailing winds def
the direction from which the wind blows into an area for most of the year
trade winds def
the prevailing pattern of easterly surface winds found blowing between the tropics and the equator
convectional rainfall def
this occurs when land is heated up and the warm air goes above it rises, cools, and condenses to give clouds and rains.
average monthly temperature in the desert
over 29 degrees in the hot summer season but 10 degrees in the cool winter season
daytime temps in the desert
over 38
nighttime temps in the desert
under 5
how much water does a desert get a year
under 250mm
humidity in the desert
25-30%
climate graph def
a graph showing the average weather for a period of time for a named location. temperature is shown as a line graph and precipitation as a bar graph.
hot desert climate def
the constantly hot and dry climate regions between 15 to 30 degrees north and south of the equator
latitude def
this is used to locate the north south position of a point on the earths surface. latitude ranges from 0 at the equator to 90 at the poles. lines of altitude run east-west as circles parallel to equator
rain shadow def
a region having little rainfall because it is sheltered from prevailing winds by a range of hills or mountains
ocean current def
any permanent or continuous, directed movement of ocean water that flows in one of the earths oceans
factors that influence the characteristics of the hot desert climate (7pts)
located in latitudes from 15 to 30 north and south of the equator.
high atmospheric pressure
long distance from oceans
prevailing winds
in areas of rain shadow
some have cold ocean current flowing past them
relief can affect the humidity and rainfall.
altitude def
the height above sea level
coriolis effect def
this causes a deflection in global wind patterns. the anticlockwise rotation of the earth deflects winds to the right in the northern hemisphere and to the left in the southern hemisphere
where are rainforests found
amazonia
central africa
indo-malaysia
HADLEY
CELL
ecosystems def
communities of biotic and abiotic things interacting with each other in an area
adaptations def
changes and mechanisms that help organisms survive in their ecological habitat
biodiverse def
describe the varity of organisms present in different ecosystems
describe the emergent layer (45-55m)
tall, large trees above the general canopy
branchless
can withstand hot temperatures and strong winds
some have buttress roots for support
might have lianas/epiphytes etc growing on them
epihytes
grow on trees and use the dead leaves and water for nutrients
describe the canopy layer (30m)
smooth oval leaves with drip tips thick and dense very little light gets through to the roots below home to 50%of the earth's plant species food is abundant
the under/sub canopy layer (15m)
little light so plants have large leaves
lots of insects
shrub layer (3-4m)
very dark (5% of sunlight reaches here)
tree ferns and small shrubs
large leaves to collect any light
floor ground layer (0m)
very dark (1% of sunlight reaches) things decay quickly
deforestation def
permanently removing forest so the land can be used for something else.
slash and burn def
a form of agriculture where the natural vegetation is cut down and burnt a method of clearing the land for cultivation
reasons and impacts of deforestation
logging plantation agriculture cattle ranching new settlement mining HEP, dams and reservoirs foods and spices climate change and carbon sinks loss of indigenous people
wadi def
the bed or valley of a stream in regions of south-western asia and northern africa that is usually dry except during the rainy season
oasis def
an isolated area of vegetation in a desert, typically surrounding a spring or similar water source, such as a pond or small lake. they also provide a habitat for animlas and people if the area is big enough.
xerophytes def
a species of plant that has adapted to survive in an environment with little liquid water.
plant adaptations for water (desert)
some store water in their leaves, roots and stems - like the prickly pear cactus.
long tap roots (60m)
wide-spreading shallow roots to absorb water when it rains before it evaporates
small, spiny leaves which give foff less moisture than leaves with greater surface areas
dersertification def
a type of land degradation in which a relatively dry area of alnd becomes increasingly arid, typically losing its sources of water as well as its vegetation and wildlife. caused by a variety of factors, such as through climate change and through the overexploitation of the land and its water resources
how to reduce desertifiation
trees are being reintroduced to the desert to stabilise the sand and act as wind breaks. the choice of trees and shrubs is extremely important - need to be able to survive, be low maintence and have other uses.
describe the impacts of an earthquake on a named area you have studied
nepal: 7.8 magnitude, april 2015, major fault line under indian plate under eurasion plate
9000 died
9000 schools destroyed
damages from $5 billion to $10 billion
describe the impacts of a volcanic eruption on a named area you have studied
eyjafjallajokull: 500m fissure, dissolved gases in molten rock along with steam generated from melting ice caused a large column of volcanic ash
airlines lost £130 million / day
Nissan forced to stop production because they could not import parts from ireland
major flood in iceland - 700 people forced to evacuate
for a named example which you have studied, explain why people live close to a volcano
eyjafjallokull:
fertile soil - (volcanic eruptions deposit the necessary minerals for a steady supply of nutrients) 1/5 of total are of iceland suitable for fodder production
tourism - eyjafjallajokull visitor centre
energy - nearly 100% from geothermal
for a named example of a volcanic eruption you have studied, describe its effects on people and the natural environment
eyjafjallajokul:
700 to evacuate due to flood
ash fall poisoned animals in nearby fields
7km of volcanic ash plumes
for a named area of hot desert you have studied, explain why the climate is hot and dry
sahara:
prevailing wind blows from the northeast takes moisture from the air and leaves dust (therefore aridness)
hadley cell: in the 25 degrees either side of the desert the atmosphere has high pressure. this forces the low pressure air closer to the ground, and as it already has little moisture the sun heats it easily. the heat then transfers to the ground.
rainshadow effect: as air makes contact with moisture, it rises above it, therefore the moisture precipitates onto the mountain peaks, leaving little to fall on the desert
for a named (hot) area you have studied, describe and explain the characteristics of its natural vegetation
saguaro cactus: waxy cuticles to prevent water loss by evapaotranspiration
acacia tree: umbrella shaped top to collect all the sunlight and water, and force plants to grow elsewhere to get minerals and nutrients
tap roots: long roots of 7-10m to get as much water as possible
for a named area you have studied, explain how the wildlife are adapted to the environment
fennec fox: thick furry feet for traction and protection
horned desert viper: horns over eyes to protect from sand and can bury itself to escape from heat and predators
sandfish lizard: lower jaws countersunk behind snout and upper jaws to stop sand getting in mouth
describe the impacts of deforestation of tropical rainforests on the global natural environment. refer to named areas affected.
loss of biodiversity and habitats
amazon has 80% of worlds documented land species’
climate change increase
amazon absorbs 2.2 billion tons of CO2 a year
desertification
fertile land becomes desert, after deforestation vegetation is much harder to grow
for a named area of tropical rainforest you have studied, explain how its characteristics are influenced by equatorial climate
amazon
proximity to equator - 214 miles
tropic of cancer and capricorn - hadley cell
close to sea on east so prevailing wind takes moisture and leaves dust
for a named area of tropical rainforest you have studied, describe the impacts of latge scale deforestation on the local environment
flash floods
football field cleared / minute
soil erosion
top soil thin and recives most nutrients. deforestaiton removes these
damage to local ecosystems
microorganims destroyed through burning
less plants grow, less evapotranspiration
for a named coast you have studied, explain what is being doen to manage coastal erosion
new forest coastline, uk
rock revetments at barton on sea, prevents flooding and futher erosion
sea wall from lymington to keyhaven, decrease wave power
beach replenishment: sediment taken away from areas where its reguarly deposited and placed in an area where it is needed
for a named area you have studied, describe the impacts of a tropical storm
hurricane floyd
4 million evacuated due to floods
500 roads made impassable (jobs)
insurance companies forced to pay out $460,000
drainage basin def
the area of land drained by a river and its tributaries. known as river basin or river catchment area
river mouth def
where the river ends when it meets a body of water such as the sea or a lake
watershed def
the boundary of a drainage basin
tributary def
a stream or small river that joins a larger one
confluence
the point where two or more rivers meet
discharge of a river def
the volume of water passing a point or location along the river channel in a given time. it is usually measured in cubic meters per second (cumecs) at a gauging station in a river
what does a drainage basin do
all the precipitaiton that falls within a drainage basin will attempt to make its way towards the river channel (underground or surface) and eventually to river mouth.
what is the input
the water added to a drainage basin in the form of precipitation
store def
surface or underground locations in a drainage basin that hold and contain water
what is the output
the losses of water from the drainage basin in terms of evaporation, transpiration and river/channel flow
aquifer def
a body of underground rock thatthrough its rock type or structures, holds water. this water can be abstracted from the rock by drilling wells and boreholes.
what is evaporation
the loss of water as it transfers from liquid to gas. higher the temp, higher the rate of evaporation
what is transpiraton
loss of water vapour from stomata in the leaves. rates depend on amount and type of vegetation
what i evapotranspiration
combined loss of water from evaporation and transpiration
what is dripflow
leaves and trees intercept precipitation and it then flows off leaves.
what is stemflow
the precipitation from dripflow flows down the stems of trees and plants
waht is inflitration
when intercepted water is released slowly into the land surface ,allowing it to enter into the soil.
impermeable def
these rocks are watertight and do not allow water to pass through
infiltration capacity def
the rate at which water infiltrates the land surface
when might water have to flow over land (overland flow)
when the soil and rock are saturated
impermeable land surface
when there is lots of trees and vegetation
porous def
describes rocks that contain many small air spaces
permeable def
describes rocks that allow water to pass through them via cracks, faults, joints and bedding planes
what is percolation
when water has infiltrated the ground and now flows/percolates through the underlying rock by gravity. rate depends on how porous the soil/rock is and how permeable the rock is
what is the top of an aquifier called
the water table
what is throughflow
when water is moving laterally as throughflow
what is groundwater flow
when water had inglitated and percolated into the rock below the soil and then moves laterally.
where does groundwater flow usually increase
where the soil and rock are very porous and permeable and during periods of steady rainfall
what is weathering
the actual breakdown of rock where it is found by physical, chemical, biological processes.
hydraulic action def
Where the weight and force of the water flowing in the river removes particles of rocks from the river channel’s bed and sides.
abrasion def
Where the river’s bedload (boulders, pebbles, gravel, sand and silt) as it rolls, bounces and collides with the channel bed and sides, removes particles of rock from the channel bed and sides.
solution def
Where some minerals (mainly the carbonate minerals found in rocks like limestone and chalk) are put into solution b the weak acids include carbonic acid which is formed as carbon dioxide gas in the atmosphere joins with rainwater and this has a great impact on the carbonate rocks and limestone in paticular
attrition def
Process which does not erode the river channel bed and sides, but breaks up the river’s bedload. It takes place when the rocks on the bed of the river are rolled along and they collide with each other and become smaller and rounder as a result. This means that the average size of rock particle (sediment) becomes smaller as it moves down towards the river mouth
traction def
Where the larger, heavier material that make up the river’s bedload (boulders, pebbles, and gravel either through rolling or bouncing are in actual contact with the river bed) is rolled along the river bed.
saltation def
Where the lighter materiak that makes up the river’s bedload (gravel, sand and silt) is bounced along the river bed.
suspension def
Where the smaller, lighter material that makes up the rivers suspended load (clay-size - a particle that is less than 0.02mm in diameter) is carried/suspended by the river
solution def
Where dissolved material that makes up the river’s solute load is moved by the river in solution.
weathering def
the breakdown of rocks in their locatiosn
erosion def
the removal of weathered material from the land by water, ice or wind
bedload def
fragments of rock which have come into contact with the bd of the river channel during their transportation
floodplain def
an area next to a river that would be affected by flooding if the river overflowed its banks
delta def
a landform, often triangular in shape, which develops where a river meets a slow body of moving water such as a lake or ocean. sediment builds up above the water level forcing the river to split into distributaries to form a delta
gradient def
how steep a slope, river channel or valley is
when does the velocity or speed of a river decrease
when the gradient of a river decreaes
when the river channel bed becomes rougher and shallower
when the river meets a large, static bidy of water such as the sea or a lake is slowed/halted.
long profile def
the shape and gradient of the river channel from soruce to mouth
cross section def
the shape across the river valley, from one side to another
source def
the starting point of a river, often a spring, melting glacier or wetland
v-shaped valley def
a valley with a v-shaped cross profile
vertical erosion def
where a stream or river erodes the river channel bed at a faster rate thatn the channel or valley sides, often leading to a narrow, v-shaped , valley
lateral erosion def
where a stream or river erodes away the sides and banks on each side of the river channel.
upper course valley
narrow steep sided v-shaped large angular boulders and stones slow flow rough channel bed predominantly vertical erosion smaller discharge
lower course
wide valley larger channel river channel often next to a floodplain smaller, rounder rocks (sand) faster flowing predominantly lateral erosion
middle course
comibation of the upper and middle features
how does the discharge of a river change through the courses
will increase from the source to the mouth as smaller tributary channels add more water to the main channel
how does velocity change through a river
increase because as discharge increases there is less friction so faster flow
how do waterfalls form: differential erosion
where a layer of more resistant rock runs across the river channel. the softer, less resistant rock is eroded at a faster rate, causing a drop in the river bed.
how do waterfalls form: sea level
sea level drops leaving the mouth of the river suspended above the lower sea level. knick point
when do potholes start to form
when a weakness or crack or fault line is exposed in the rock in the riverbed and differential erosion takes place
meander def
a bend in a river
river cliff/bluff
a steep section of the river bank caused by fast-flowing water eroding the outside of the bank of a meander
slip-off slope/point bar
a gentle slope on the inside of a meander formed by deposited on the inside of a meander where the river flows more slowly and less energy.q
oxbow lake def
a lake, often semi-circular in shape in a river floodplain, where a meander has been cut off from the river channel
bankfull discharge
the river discharge when the river channel full to the top of its banks and is just about to spill onto its floodplain.
alluvium
sediments which are depositied by rivers
levee
a raised bank of sediment along the sides of a river channel
what happens to a meander ove rtime
its neck becomes very narrow. the river may break through the neck - often during high flow conditions. this may result in a section of the river channel being isolated from the main river chanel to form an oxbow lake. with time these dry out to form oxbow scars.
what is the outside bank of the river called
river cliff or bluff
what is the inside bank of the river called
the slip off slope or point bar
describe the river cliff/bluff
deep, fast flowing and often undercut by river, large sediment size
describe the slip off slope or pointbar
shallow, slow flowing. small sediment size
for a named volcano you have studied, explain the causes of an eruption
eyjafjallajokull
North american and eurasion plate
The two plates are moving apart (constructive) due to ridge push along the Mid-Atlantic Ridge. As the plates move apart, magma fills the magma chamber below Eyjafjallajokull.
describe the causes of an earthquake on an area you have studied
caused by a sudden thrust, or release of built-up stress.
Indian Plate is diving underneath the Eurasian Plate.
magnitude of 8.1
