Physical Geography Earth revision notes
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sam_atwalbtinternetcom (student)
EARTH
Key terms
L’Aquila – Italy
Key facts
Occurred on 6th April 2008 at 3:32am . 6.3 on the Richter scale and focus was 9.4km deep . 70,000 made homeless . 300 died and 1500 injured .
Cause
Occurred at a destructive plate margin . Between Eurasian and African plates . The African plate was sub ducted by the Eurasian plate (went underneath)
Primary Effects
In Onna , 8/10 buildings were destroyed and 1/10 people were killed . Up to 1000 buildings were destroyed including the L’Aquila cathedral and fossa bridge . Fires were caused and spread extremely quickly , most people were asleep so didn’t notice the fire until it was too late .
Secondary Effects
The after shock was up to 5 on the Richter scale and this caused more deaths and damage . A landslide was created because of a broken water pipe in Paganica , this killed and injured more people .
Immediate responses
There was a camp for the homeless which had food and medical care , and the army were called from all over Italy to help rescue people . Cranes/diggers helped remove rubble slowly as there could be people underneath . Dogs were also sent in for extra help .
Long term responses .
Italy spent $15 billion on repairs . Many people were made redundant because their work places has collapsed . The aftershocks meant the rescuers had to run in and out of the buildings fast . The bills were stopped as the government want to help out .
Kashmir
Key facts
Occurred on 8th October 2005 in Kashmir , Pakistan at 8.50am . It was 7.6 on the Richter scale . The damage cost $5 billion . 250 times more people died than L’Aquila
Causes
Occurred at the destructive plate margin . The Indian plate was sub ducted by the Eurasian plate .
Primary Effects
80,000 people died . The main cause of death was collapsing buildings . Hundreds of thousands were injured . Some villages were fully destroyed and thousands of buildings were destroyed . 30,000 square miles was destroyed . 75m fault line . Sewage and gas pipes burst .
Secondary effects
80% of Uri was destroyed . People died from landslides and collapsed buildings . Water supplies , electricity and main roads were shut off . 3 million were made homeless . Many diseases started to spread because of the dirty conditions . Diarrhoea started to spread , this was the main disease . Many people tried to rebuild their homes but couldn’t’;t because of the freezing conditions .
Immediate responses
People started digging with their hands because they didn’t have diggers and cranes . They couldn’t get to everyone quick enough causing deaths that could have been avoided .
Long-term responses
Help took weeks to get there . Within a month all the supplies had been distributed . 40,000 moved to a new town . A new health care was made . Training was given out to help rebuild earthquake proof homes .
Tsunami
A tsunami is usually triggered by an earthquake . The crust shifting is the primary effect . The secondary effect of this is the displacement of water above the moving curst . This is the start of a tsunami .
A tsunami may be 200km in length and only 1m high out at sea there is rapid gain in height as they approach land . They can travel at speeds of 800kpm but slow , reduce in speed and increase in length as they approach land .
. If one tectonic plate is dragged beneath another , stress on the boundary causes the edges of the plates to flex and deform
2. The flexing of the plates displaces the entire column of water vertically .
3. Quickly the water column splits into two with one wave travelling out to sea and the other towards the cost .
4. The tsunami comes ashore and can surge far inland . Often secondary weaves are far more powerful than the initial one .
2004 boxing day tsunami
Date : 26th December 2004
Plate movement : Indo-Australian plate sub ducted the Eurasian plate .
9.1 on the Richter scale
Affected areas : Thailand , Sri Lanka , Malaysia , Kenya , Somalia , India and Indonesia
Highest waves :25m
Deaths L 220,000
Injuries: 650,000
Homeless : 2 million .
Primary Social effects
* In Sri Lanka , the tsunami washed away a train killing 1700 people
* 2 million people were made homeless
* 230,000 were killed
* 650,000 were seriously injured
* hundreds of fishermen went missing off the southern Indian coast and witnesses have reported to see bodies wash up on the beach .
Primary Economic effects
66% of the fishing fleet and industrial infrastructure in the coastal regions around the Indian ocean were destroyed .
Primary environmental effects
* The magnitude 9 earthquake caused land in northern Sumatra to shake up for 10 minutes
* 42 islands in the Maldives were flattened
* vast areas of protective coral was destroyed
* sea water was driven up to 2km inland causing widespread flooding
* coastlines around the Indian ocean had their shape changed
Secondary social effects
* Survivors Have continued to suffer years of trauma having lost friends and family
* Water borne diseases such as cholera and typhoid were spread in the aftermath
* In Banda Aceh , 150,000 were killed and parts of the city were permanent submerged
Secondary Economic effects
* Tourists visits tot the northwest of the coast of Sumatra has virtually stopped .
* In Galle , one year on the main fish market has been rebuilt but the infrastructure supporting the industry is not . Fishermen do not have enough refrigerated trucks to transport fish along the coast , instead they sell their stock on the highway
* The uk public donated £330 million to charities involved in aid and rebuilding
Secondary Environmental effects
* The salt water has damaged drinking water supplies . These will be affected for years
* Four major tsunamis were triggered with waves 30m high
Immediate Response
Foreign counties sent ships , soldiers and a team of specialist to help rescue people , distribute food and water and begin clearing up . Within days hundreds of million of pounds had been pledged by foreign governments , charities , individuals and business to help survivors with supplies , medical care and shelter . The dead were buried to stop the spread of diseases . There was a battle for supplies . Red cross sent thousands to help rescue and friends helped rescues .
Long – term response
Billions of pounds have been pledged to help rebuild the infrastructure of the counties affected . As well as money , programmes have been set up to help with employment and rebuilding homes . There is now a tsunami warning system in the Indian ocean . In some counties there is now disaster management . Volunteers have been trained so they are aware what to do in another tsunami . A school was built for the orphans . $14 billion was raised . 4 years later aid has helped rebuild homes , roads and schools .
Prediction
Prediction: Trying to forecast when an earthquake will occur . This way you can easily evacuate and be ready for an earthquake . Although this isn’t always accurate and can panic people . A seismograph is used to predict earthquakes . It senses the tremors on the earths surface and is recorded with a pen and vibrates at the same rate as the ground . The longer the lines , the higher the magnitude .
Protection
Protection: constructing buildings so they are safe and to an appropriate standard to withstand movement .
There are aseismic buildings (earthquake proof buildings) . When an earthquake occurs you’ll be less panicked of the building collapsing . Although it is expensive . You shouldn’t build your home to clay as this is unstable , a strong foundation is needed . There should be rubber around your home , to absorb the vibrations .
Protection in buildings
* Computer controlled weights on roofs to reduce movement
* Steel frames that reduce the swaying of the building
* Automatic window shutters to prevent falling glass
* Open areas where people can assemble if evacuated
* Foundations sunk into the bedrock , avoiding clay as this is unstable , a strong foundation is needed . There should be rubber around your home , to absorb the vibrations .
* Birdcage interlocking steel frame – they sway which reduce the chances of building falling over .
* Outer panels flexibly attached to the steel structure
* Fire-resistant building materials
* Roads to provide quick access for emergency services (get away from tall buildings before they collapse)
What you will need in an earthquake : water , food , first aid kit , radio , batteries , cash , important documents eg passport , clothing , torch and medication .
Preparation
Preparation – Organising drills and codes of practice so people know what to do in the case of an earthquake . Although this reduces panic , you could spend time preparing and it may not even happen .
Measuring earthquakes
Mercali scale : records the intensity of an earthquake by measuring the effects of an earthquake
Richter scale : assigns a number to indicate the amount of energy released during an earthquake
Earthquakes
Earthquakes are vibrations in the earth’s crust that cause at the earth’s surface . They are highly unpredictable . When a plate goes past another plate , the friction builds up pressure . The plates move because of convection currents . When the pressure keeps building up between the two plates , the plates energy which causes the seismic waves . Seismic waves is the earthquake . They mostly happen at conservation , destructive and constructive plate boundaries .The point above this above ground is called an epicentre , underground it is called a focus .
There are two kinds of waves . Primary waves go up and down they travel the fastest . S waves move back and forth , they arrive second . Earthquake energy moves radically outwards .
Super volcano
A super volcano is a mega colossal volcano that erupts at least 1000km^3 of material . A normal volcano emits roughly 1km^3 .
Key differences
* Shape – they are flat surrounded by higher mountains in contrast to the gentle or steep sided mountain . They have a caldera not a crater
* Size – much bigger but harder to notice
* Scale – more violent , less frequently eruptions , has wider effects , emits more material (ash or magma)
* Impact – have devastating consequences with 200km . All life gone and serious impact on continents unlike volcanos , where effects are more localised .
Formation of a super volcano
. Rising magma cannot escape and a large budge appears on the surface
2. Cracks appear in the surface and gas and ash erupt from the magma chamber
3. The magma chamber collapses , forming a depression called a caldera .
Yellow Stone Super Volcano
It’s a hotspot , the plate goes over it . When a plate goes over a hotspot , the plate melts the earths crust and a large magma chamber is formed . It erupted 2 Million , 1.3 million and 630 million years ago . It’s a massive tourist attraction and it has geysers (hot water erupts into the air). The magma chamber is 80km long , 40km wide and 8km deep .
Yellow stone erupting
* Burns , kills and buries
* Everything is tens of miles will be destroyed
* Triggers a mini ice age
* Blocks sunlight for all continents
* 1000 of cubic km of ash , rock and lava will be thrown out
* Ash settles over hundreds of square km
Volcanoes
Earth is made up of moving plates . Convection currents make the plates move . The core heat is burning hot , as the heat passes up the temperature decreases .
Crust relatively speaking is as thin as the skin of the apple . Oceanic crust (Sima) is layer mainly consisting of basalt averaging 6 to 10km in thickness . At its deepest it has a temperature of 1200 degrees Celsius . Continental crust (sial) can be up to 55km thick . Mantle is made mainly of silicate rocks rich in iron and ...
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Volcanoes
Earth is made up of moving plates . Convection currents make the plates move . The core heat is burning hot , as the heat passes up the temperature decreases .
Crust relatively speaking is as thin as the skin of the apple . Oceanic crust (Sima) is layer mainly consisting of basalt averaging 6 to 10km in thickness . At its deepest it has a temperature of 1200 degrees Celsius . Continental crust (sial) can be up to 55km thick . Mantle is made mainly of silicate rocks rich in iron and magnesium which are kept in a semi-molten state . It extends to a depth of 2900km , with temperatures reaching 5000 Celsius degrees . Core consists of iron and nickel . The outer core is kept in a semi-molten state but the inner core is solid . At the centre of the earth the temperatures may reach 5500 degrees Celsius .
Active volcano is liable to erupt . Dormant (potentially active) a volcano which hasn’t erupted for many years . Extinct volcano is a volcano that hasn’t erupted for thousands of millions of years .
Volcanos are distributed as linear curves around plate boundaries . The most amount of volcanoes is one the Pacific boundary also known as the ring of fire . There is also volcanoes on the west coast of south and north America . Sometimes volcanoes form a hotspot (away from a plate boundary) because the magma is close to the surface.
Composite volcano
* Steep and narrow
* Infrequent eruptions
* Occurs at the destructive boundary
* Violent eruption
* Thick , quick setting acidic lava
* Human activity , path up the side of the volcano made by tourists visiting the site in response to the eruption .
* Physical activity – gullies in the ash flow caused by rain water after the eruption . Fertile land on the slopes due to the rapid break down of the lava rich in minerals . Large crater of volcano leading down to the vent . Steep sided convex slopes made of ash and lava , possibly cause by pyroclastic flows during the eruptions
Shield Volcano
* Frequently erupts
* Non-violent eruptions
* Gentle slope
* Wide base
* Runny lava
* Occurs at a constructive boundary
Predicting eruptions
* Before an eruption , earthquakes shows the magma moving up
* You might get gases
* The water temperature increases
* A volcanoes shape changes . Tilt meters measure the change , so do geometers .
* Use satellites to measure movement
* Look at past eruptions
2010 April eruption
Primary Effects – explosions caused electrical storms and sulphur dioxide was released
Secondary effects – 8 million people were stuck at the terminal , businesses lost money as goods had to be thrown allow , 10 million flowers thrown away .
Immediate response – 800 people evacuated and airlines closed down
Long term response – oil prices went down £4 and airline stocks dropped 3-4%
Plate boundaries
* Collision plate boundary – it when two plates of the same density move together . The material between them rises to form mountains . The Himalayas are an example of this .
* Conservative plate boundary – is when 2 plates slide past each other sometimes one is going faster than the other . No volcanos form but earthquakes occur
* Destructive plate boundary – the plates move together , one goes under the other . The oceanic plate goes under the continental plate because its denser . The friction causes the plate to melt down to magma . The magma rises to the surface to form a volcano . Friction is caused by a build up of pressure which causes an earthquake . Continental plates are older and wont melt . A subduction zone is when a plate goes under another .
* Constructive plate boundary – the two plates move apart because of convection currents . Volcanoes don’t erupt with much force . When plates don’t move slowly you don’t get an earthquake .
Case studies
Economic effects : effects on property , transport and the industry
Environmental effects : the way the landscape is damaged
Social effects : the way in which people suffer from injury , death and destruction of their homes .
Primary effects – the immediate effects , what problems did it cause eg homelessness
Secondary effects – the after effects that occur as an indirect consequences of the disaster later on eg loss of business
Immediate response – how people react straight afterwards eg search for survivors
Long term response – what happens days/months/years later eg rebuilding earthquake proof buildings .
Fold mountains
Rivers erode material from land surface and transport it to sea . Sediment is deposited on ocean floor , layers build up over time forming sedimentary rock due to compression . Plates move together at destructive / collision boundaries . Rocks crumple as a result , forming fold mountains with anticlines and synclines . Fold mountains can also form at subduction zones where the continental crust crumples as it meets the oceanic crust . Here also , the oceanic crust divers below the continental crust . At this point , the sea is very deep and it is here that there are ocean trenches .
Fold mountain formation
. Collision margins – result in fold mountains
2. Rivers carry sediment to the oceans where it is deposited in layers
3. The area of the ocean in which the sediment are deposited is called a geo syncline .
4. These layers are compressed and form rock
5. Continental drift is the process where plates move
6. Convection currents are responsible for starting plate movement
7. Continental plates moving together result in a collision margin
8. As the continents move towards each other the sediment (now rock) buckles to form folds
9. The nearer the continents are to each other , the larger the folds
0. Many mountains also break a little in the process giving faults (cracks) . Eventually the two compress the rock so much it forms fold mountains and valleys
The fold mountains are on the west coastline and in Europe , and the top of India in a cluster
COASTS
Key terms
Coast – a narrow contact zone between land and sea that is constantly changing due to the effects of land , air and sea processes.
Beach – a deposit of sand or shingle at the coast , often found at the head of a bay
Fetch – the distance over which the wind goes over the sea
Crest – the top of a wave
Swash – the forward movement of a wave up a beach
Backwash – the backward movement of water down a beach when a wave has broken
Constructive wave – a powerful wave with a strong swash that surges up a beach
Destructive wave – a wave formed by a local storm , that crashes down onto a beach and has a powerful backwash
Mass movement – is the downhill movement of material under the influence of gravity
Marine processes of erosion
Erosion is the destructive waves wearing away at the coast . There are four main processes which can wear away the coast . The top half of the cliff is affected by weathering (sub-aerial) and the bottom half is affected by erosion (sub-marine) .
Four types
. Hydraulic power – the sheer power of the waves , waves hitting against the cliff
2. Abrasion / corrosion – the effect of rocks being flung at the cliff by powerful waves , rocks being thrown at a cliff by a wave .
3. Attrition – the knocking together of pebbles , making them smoother and smaller
4. Solution –The dissolving of rocks , such as lime-water and chalk
Headland and bay
Resistant (harder) rock left as a headland . Less resistant rock is worn away – bay . Headlands are most commonly chalk , limestone and sandstone.
Weathering
Mechanical Weathering
Weathering that does not involve chemical change . Freeze thaw weathering : weathering involving repeated cycles of freezing and thawing . Water collects in the cracks of the rock , water freezes to form ice , expansion causes the cracks to enlarge , repeated freezing and thawing cause rock fragments to break off and collect as scree at the rock face . Scree is little bits of cliff that have fallen off .
Chemical Weathering
Weathering that involves a chemical change taking place . Solution – dissolving of rocks or minerals by rain water .
Biological weathering
Weathering caused by living organisms such as tree roots or burrowing animals .
Weathering : the breakup or decay of rocks in their original place or close to the earth’s surface .
International responses
997- Kyoto Protocol – agreed by nearly every country in the world expect the usa and 4 others which want developing nations to have to cut their emissions as well .
998- The ipcc (international panel on climate change) established to coordinate scientific research .
uk
The UK is a leading nation , they have committed to cutting CO2 levels by 80% of the 1990 level by 2050 . Climate change act 2008- the uk was the first country in the world to have a legally binding long-term framework to cut carbon emissions . 80% of the uk’s emissions come from burning fossil fuels .
Coastal transportation
The four main types of sediment transportation are
. Solution – minerals are dissolved in sea water and carried in the solution . The load is not visible . Load can come from cliffs made from chalk or limestone and calcium carbonate is carried carried along in the solution
2. Saltation – load is bounced along the sea bed . Currents cannot keep the larger and heavier sediments afloat for long periods .
3. Traction – pebbles and larger sediments are rolled along the sea bed
4. Suspension – particles carried within the water
Long shore drift
Groynes are evidence of long shore drift . Long shore drift : the transport of sediment along a stretch of coastline caused by waves approaching the beach at an angle.
In areas where the flow of water slows down (waves lose energy) Sediment can no longer be carried or rolled along and has to be deposited . Coastal deposition most commonly , occurs in bay where the energy of waves is reduced on entering the bay . This explains the presence of beaches in bays and accounts for the lack of beaches in headlands where wave energy is much greater .
Cliffs
Strategies that are locally successful but can cause problems elsewhere
. Groynes protect local areas but can cause narrow beaches to form further down the coast , eg Cowden farm (south of Mappleton) is now at risk of falling into the sea .
2. The material produced from the erosion of Holderness is normally transported south into the Humber Estuary and down the Lincolnshire coast . Reducing the amount of material that is eroded and transported south increase the risk of flooding in Humber Estuary because there is less material to slow the flood down .
3. The rate of coastal retreat along the Lincolnshire coast is also being increased because there is less material being added on .
4. Spurn Head is at risk of being eroded away because there is less material being added on .
5. Bays are forming between the protected areas and the protected areas are becoming headlands which re being eroded away more heavily . This means maintaining the defences in the protected areas is becoming more expensive .
Methods of coastal defence
Rock armour / Riprap – Hard engineering . Piles of boulders , 10 tonnes or more are dumped at the cliff foot . The gaps between the rocks allow water to enter so the energy of the waves is being displaced very effectively . Can provide interest to the coast (fishing) . They can be obtrusive and do not fit with the local geology . £1000-£4000 per metre . An effective methods but limited life span (10 years)
Wooden Groynes – Hard engineering
£10,000 each at 200m interval , built at right angles to coast lines . Stops the movement of material along the beach . Not too expensive . Unnatural and unattractive . This helps to keep sand on the beach and protects the land .
Rock Groynes
£5-10,000 . Looks more naturals . Lasts 10 years . More expensive than wooden groynes . Stops long shore drift , keeps sand on the beach and protects the land .
Gabions
Large steel mesh cages filled with rocks . Aligned at right angles . Similar job to wooden groynes . Lasts 20-25 years because the steel rusts .The cages also absorb the energy of the waves .
Curved seawall
Sea walls absorb the impact of the waves . Lasts for 75 years . The curved design reflects the energy back out to sea . Can cause erosion . £6-10,000 per metre
Accropodes
Concrete Accropodes mesh together more than irregular riprap and absorbs the energy from the waves . Looks appealing .
Flood gates
The gates can be closed at high tide to keep the water out . It works but id doesn’t protect the sea wall which may eventually erode .
Soft engineering – a sustainable approach to managing the coast without using artificial structures Eg beach nourishment and dune regeneration .
Hard engineering – building artificial structures such as sea walls aimed at controlling natural processes eg rock armour .
Beach nourishment
£3000 per metre , relatively cheap and easy to maintain . Blends in with the existing beach . Increases tourism and needs constant maintenance. Additional sand makes the beach look higher .
Dune regeneration
£2000 per metre , cheap . Popular with the locals and wildlife . Time consuming to plant . Damaged by storms . Stops sea hitting the coast . They are hills of sand
Marsh creation (managed retreat)
Creates a much needed habitat for the wildlife. They become salt marshes and are arable . £5-10,000 per 100mx100m . Allows areas to become flooded . Farmers get compensated . Land will be lost .
Sea level rising
There will be increased erosion and flooding events because more cars / technology are causing high pollution are being made . Pollution causes green house gases , which causes global warming . This heats up the earth’s overall temperature which melts the ice caps . Causing higher sea levels . Increased sea levels . Increased storm events and stronger wind due to the climate change . Isostatic adjustment when NW Scotland is recovering from weight of ice SE England sinks .
Thermal Expansion – absorbs heat of the atmosphere , sea level rises as it takes up more room .
Melting sea ice will have no direct high effect on sea levels . Ice is water , therefore there is no change in the volume .
Melting land ice eg Greenland will increase the amount of water in the oceans but may not significantly affect sea levels .
Eustatic Charge – is the global rise or fall of sea levels . This is a global change
Economic effects
* Valuable agricultural land which can be at greater risk of flooding
* The broads would flood causing a loss in tourism .
* Thames Barrier currently protects buildings worth £80 billion.
Environmental effects
* Erosion rates are likely to increase threatening coastal settlements such as over strand and Hassisburgh .
* Areas of salt marsh are being squeezed between sea walls and rising sea
Social effects
* In 1953 East Anglia suffered terribly from a storm surge which killed 300 people .
* Settlements such as King’s Lynn may be under threat as sea levels rise .
Spits
. Material is eroded along the coast
2. Material is transported by longshore drift until the coastline changes direction
3. Material is deposited and extends into the sea
4. If the wind changes direction the end may become curved .
5. Over time , on the landward , more sheltered side , a salt marsh , mud flat may form
Landforms created by deposition
Beaches – constructive waves rather than destructive waves
Sheltered areas where waves aren’t powerful
Clear source of sediment nearby
Deposition outweighs any erosion
They are accumulation of sand and shingle (pebbles) found where deposition occurs at the coast
Sandy beaches
Often found in a bay – bay head beaches .
Wave refraction – bay curves – bends around – mirroring bay – not as powerful – drops material
Pebble beach – high energy waves , cliffs have been eroded .
Spits – a finger of new land of sand and shingle , out into the sea from the coast .
Salt marshes
On the landward sheltered side of a spit where the water is calm , mudflats and salt marshes form . These are important habitats for plants and birds .
. Accumulation of mud and salt
2. Mud begins to break the surface – above the water – mudflows are formed
3. New plates start to colonize (form)
Cliff collapse
. Soft clay cliffs are permeable (soak up water) and hold rain water .
2. Sea attacking / eroding ( abrasion / hydraulic power) the base of the cliff , causing a wave cut notch to form . At the same time heavy rainfall causes the soft clay to become saturated(full of water) , causing a slip plane to from
3. The weight of the clay causes the cliff to slump or collapse .
Keyhaven salt marshes
This is situated between Hurst Castle spit in the west and Lymington river to the east . This reserves extends to over 2000 acres of salting’s and mudflats thus forming SSSI . SSSI is a site of special scientific interest . The area is carefully monitored and managed to maintain its rich biodiversity . The marshes east of the Lymington river become a local nature reserve in 1995.
Wildlife
The salt marshes and mudflats together with associated shingle ridges , support nationally and internationally a number of important birds . During the breeding season the most frequent bird is the black-headed owl with up to 7000 pairs regularly nesting in the reserve . Several species of Tern and breed here , including little , common and sandwich terns . Among breeding waders the most conspicuous are oyster-catcher , ringer plover and redshank . The plants on the reserve are also of great importance . Species common cord grass , glassworts , sea-pursiane and sea aster which looks like a Michaelmas Daisy . The uncommon golden –sapphire is however perhaps the most common .
* Cord grass – spiky , untidy looking grass that grows fast on mudflats
* Sea lavender – attractive , colourful flowers attract wildlife
* Bird – oystercatcher , feeds and nests in the salt marshes .
* Common blue butterfly – resident butterfly , commonly found on higher marshes .
* Wold spider – clings for hours to submerged stems of cord grass waiting for low tide and food
The process of vegetation succession on salt marshes
. A salt marsh begins life as an accumulation of mud and slit in a sheltered part of the coastline for example in Lee of a spit or bar .
2. As more deposition takes place , the mud begins to break the surface to form mudflats
3. As the level of the mud rises , it is less frequently covered by water . The conditions become less harsh as the rainwater begins to wash out some of the salt and decomposing plant matter . This improve the fertility of the newly forming soil . New plant species such as sea asters and sea lavenders start to colonize the high marsh area and gradually over hundreds of years a succession of plants develops . This is known as vegetation succession .
4. Salt tolerant plants are called halophytes . This is a species that is adapted to the harsh conditions including being under water twice a day at high tide . It’s tangle of roots also helps to trap sediment and stabilize the mud in the low marsh
5. These plants trap more sediment and contribute organic matter when they die . These processes help the salty marsh to grow .
6. Salt-tolerant plants such as cord grass soon start to colonize the mud plants . These early colonisers are called pioneer plants . Cord grass is tolerant of the salt water and its long roots prevent it from being swept away by the waves and the tides .
7. New plants start to colonize the area inland as it is more fertile and salinity has decreased and gradually over hundreds of years a salt marsh develops . This is known as vegetation succession . plants found further inland include shrubs and brambles
8. Eventually the salt marsh will grow further and an even more plants will colonise the areas it is much more fertile and much less salty until the climax community of alder and ash trees is .
Why the marshes are undertreat
* Keyhaven salt marshes are under threat from the construction of groynes to the west which were designed to trap sediment for some of the south coast beaches . The effect of this has been to starve the spit behind which the salt marsh ecosystem has formed and relies upon for shelter . This has weakened the spit as it has been eroded and some plants have died .
* Increasing tourism – careful management is needed to prevent damage by trampling , parking and pollution . Damage comes from boats moored in the area too .
* Damage during storms – in December 1989 a storm pushed part of the shingle of the spit on top of the salt marsh . This meant the spit was not protecting between 50m and 80m of it anymore and is was eroded in less than 3 months .
* Animals also graze on the marsh which damages it .
* The marshes are retreating by 6m a year and sea level rise is a threat
Sustainable management to make sure that the marshes are conserved
* In 1997 550m of rock armour and large amounts of shingle (beach nourishment) were used to increase the height and width of the spit to stop it being breached and therefore keeping it as protection for the marsh .
* Keyhaven marshes are an SSSI and part of a nature reserve . This means that is sustainably managed by limiting access and monitoring and protecting the wildlife .
* In December 2007 the reserve opened its improved footpath around Moses Dock . This work forms part of an ongoing programme of safety and access improvements around the whole of the nature reserve that will be of great benefit to walkers and all users of these routes , including families and wheel chair users . Thanks to sustained efforts over the last few years the reserve is now much more accessible to wheel chair users and is better equipped to cope with 250,000 plus visitors per year than ever before .
* Other traditional uses of the area such as non-commercial bait digging and the collection of gull eggs are permitted under a series of licenses and leases .
Mappleton
3KM South of hornsea . Protect this because its expensive to rebuild , there’s 30 homes and a busy main road . Built in 1991 : blocks of granite for groynes from Norway . This stops the cliffs eroding so quickly . Although makes the erosion go faster further down south (sediment starvation) . the groynes cost £2 million . This is a town in Holderness . The annual rate of erosion is 2m . The reason for this is that : the bolder clay is soft and erodes quickly , destructive waves , sediment starvation , hydraulic power and 10 waves per minute .
Mass movement
Both mass movement and weathering provide provide an input of material to the coastal system . Much of this material is carried away by the waves to be deposited elsewhere along the coast .
Types of mass movement
* Rock fall – fragments of rock break away from the cliff face often due to freeze thaw weathering
* Landslide – blocks of rock slide downhill
* Mudflow – saturated soil and weak rock flows down a slope
* Rotational slip – slump of saturated soil and weak rock along a curved surface
Mass movement – the shifting of loose material down a slope
Sea Stack
The formation of a sea stack : waves attack a crack in the headland . This is enlarged to from a cave by the pounding of the waves compressing air in the rock face and abrasion where material carried by the water is flung against the cliff . In this way , the cave is made bigger and if there is one on either side of the headland an arch will form as the result . Continued erosion will wear away the rock supporting the arch and this will collapse . This will leave an isolated piece or pieces of rock separated from the headland which is known as a sea stack .
Cliffs
Impacts on people’s lives
* Homes near the cliff (eg in Swansea) are at risk of collapsing into the sea
* Property prices along the coast have fallen sharply for those homes at risk from erosion
* Accessibility to some settlements has been affected because roads near the cliffs tops are at risk of collapsing into the sea (eg Southfield Lane which runs between Skipsea and Ulrome has been closed )
* Businesses are at risk from erosion so people will lose their jobs (eg Seaside caravan park , Ulrome which is loses an average 10 pitches a year)
* The gas terminal at Easington is at risk (only 25m from cliff edge) . This terminal accounts for 25% of Britain’s gas supply
* 80,000m^2 of farmland is lost each year . This has a huge effect on farmer’s livelihoods
Environmental impacts
Some SSI’s are threatened – eg the lagoon near Easington are part of the SSSI . They lagoons are separated from the sea by a narrow strip of sand and shingle (a bar) . If this is eroded it will connect the lagoons to the sea and they would be destroyed
Waves
In the open sea , despite the wavy motion of the water surface , there is little horizontal transfer of water . It is only when the waves approach the shore that there is forward movement of water as waves break and wash up the beach . Speed , time and distance affect the wave formation.
Constructive Waves
Formed by distant storms . They are long in relation to their height . They break gently on the beach so that the swash up the beach is stronger than the backwash carrying them away . 6 – 9 waves per minute . They carry large amounts of sand and shingle that is deposited and builds up on the beach
Destructive waves
The backwash is much stronger than the swash that rocks , pebbles , and sand are carried back out to the sea. They are high in relation to their length . They are frequent , 11-15 waves per minute . They are formed by local storms close to the coast and removes sediment from the beach
Formation of stacks and stumps
. The sea attacks the foot of the cliff and erodes areas of weakness such as joints and cracks
2. The cracks in the cliff gradually get larger , these will develop into small caves
3. Further erosion widens the cave . This will eventually form an arch , passing through the headland
4. A combination of waves attack the base of the arch and weathering of the roof of the arch (by frost , wind and rain) weakens the arch
5. The roof of the arch has collapses to create a stack
6. A stump is created as the stack continues to erode . This will be covered by water at high tide
Recycle for Hampshire
In 2011 22.9 million tonnes of Rubbish were collected per person in England . Landfills release methane . Study area –Farnborough , Hampshire . 214 resident questionnaires , 10 interviews ( 2 members of the council)
Recycle for Hampshire is a behaviour change campaign which attempts to reduce the amount of waste that goes to landfill.
Initiatives in place:
* A school’s recycling programme
* Recycling door steppers
* Larger recycling bins , smaller waste bins
* Website , social media , adverts to spread the message
* Citizen panels
* Performance charts are available to the public
50% recycling bins are full when collected which means people are recycling . More people recycle than reduce or reuse .
WEATHER
Winter Flood December 2013- January 2014
Introduction / Traffic / Transport
There was very strong winds in Scotland and northern England which leads to a winter storm . The flood occurred on 5th December 2013 . Two people died . In Glasgow , Edinburgh and Aberdeen the lights were cancelled . Scotland’s rail network shut down . Rail services were cancelled due to the fallen trees . . Gatwick was affected by the flooding . There was a few traffic accidents . In wales , trees blocked the roads and rail ways were flooded . 23rd – 24th December had particularly heavy rain to SE England and Wales . Dorset has 50-70mm of rain . The main flooding was in the SW England and South wales .A large area of low pressure in the north Atlantic , driving strong winds and coinciding with high spring tides resulted in exceptionally high waves . In Scotland this was the wettest month since 1910
Services such as schools , hospitals / power
00,000 homes were left without power in Western Scotland Northern Ireland . This carried on through Christmas , 50,000 homes were left without power
Impacts on businesses / agriculture
Many trees fell over and blocked roads . River Nirth burst its banks . There was also parts of flooding from the River Thames and River Severn in Gloucestershire . The spring waves and large waves were combining to cause major floods on coastal areas .
People’s homes / lives generally
Near the east coast of England several hundred homes were flooded (Boston and Lincolnshire) . Thousands of residents were evacuated from their homes . Several homes collapsed in the sea because in Hemsby Norfolk there was cliff erosion . In Devon a man and a teenager were swept away by the sea .
Flood Warnings
* Avoid non-essential journeys
* Remain extra vigilant
* Protect yourself
Weather and Climate
Weather – day to day conditions of the atmosphere involving a description of temperature , precipitation , humidity , cloud cover , sunshine , air pressure , wind direction and speed .
Wind direction – where it comes from
Air pressure – high air pressure is dry , low air pressure is wet
Precipitation – anything that comes out the sky
Climate – the average weather conditions recorded over a period of at least 30 years
Prevailing winds – the dominant wind direction
Water cycle
. The sun evaporates the water
2. The air cools and condenses
3. The minute water particles join together , become too heavy and fall as rain
4. The rain returns to the sea via rivers
Evaporation – the process where water changes from liquid to vapour
Condensation – the process by which cooling vapour turns into a liquid
Surface run- off – the movement of water over land , possibly as a river
Transpiration – plants giving off water vapour from their leaves
Ground water – water that has sunk through the soil into the rocks below
Relief rainfall – a collection of these minute water droplets is known as a cloud
There are 3 main types of rainfall : relief , convectional and frontal depressions . Rainfall occurs because air rises . Air contains water vapour and as the air rises it cools and condensation occurs . This means the water vapour returns back into minute droplets of water and falls as rain
Relief rainfall
The west gets more water because the winds come from over the Atlantic and are full over water vapour . This is because relief rainfall and the uplands in the west . In the west there are hills / mountains . The east is in the rain shadow
Convectional rainfall
The rains fall you get in summer when the temperatures are higher . The SE is higher
. Sun heats the earth
2. The earth heats the air above it
3. Hot air rises quickly because its less dense
4. Water vapour in the air cools and condenses into water droplets
Frontal rain – depressions
When hot air and cold air because the warmer air is lighter it rises above the cold air , it cools and condenses and it rains . The depression moves east to west hence why its drier here .
Factors that affect temperature
* Latitude – how far you are from the equator . The south of the UK is at a lower latitude , the suns at a higher angle in the sky – more overhead so we get more heat energy
* Altitude – how high up you are . The higher you go up , the colder it is . Every 100-150m you go up , it gets 1 degree Celsius colder . More exposed tot eh wind , it rains a lot more causing clouds to block more sunlight .
* Prevailing winds – the dominant wind direction
* Distance from the sea . The sea takes longer to heat up and cool down than land . Places on the coast are cooler because the sea takes longer to get warmer . In winter you get a warming affect because the sea is still cooling down .
* The north Atlantic drift is a warm ocean current that brings higher temperatures to the west of the UK . The north Atlantic drift starts its journey in the gulf of Mexico . This causes places like Cornwall to be 7 degrees Celsius in January and the east to the 5 degrees Celsius .
Air masses are huge blocks of air . They can be damp or dry , warm or cold , depending on where they came from and over what type of surface they have travelled .
From the North you get Artic cold . From the NE , its polar continental , dry and cold . From the SE , its tropical continental , warm and dry . From the SW , its tropical maritime , wet and warm . From the NW , its polar maritime , wet and cold . All towards the UK.
Depressions (low pressure system) form when a cold air mass meets a warm air mass .The junction between these two different air masses is called a front . The depression moves west to east
Cold sector
Passage of the cold front
Warm sector
Passage of the warm front
Ahead of the warm front
Pressure
Continues to rise
Starts to rise
Steadies
Continues to fall
Starts to fall steadily
Temperature
Remains cold
Sudden drop
Quite mild
Continues to rise
Quite cold . starts to rise
Cloud cover
Clouds thin with some cumulus
Clouds thicken , sometimes with large cumulonimbus
Clouds may thin and break
Cloud base is low and thick , nimbostratus clouds
Cloud base drops and thickens , cirrus and altostratus
Wind speed and direction
Gets windy
Speeds increase , change in gale force / wind direction
Remains steady
Wind changes direction and becomes blustery with strong gusts
Speeds increase
Precipitation
Showers
Heavy rain , hail , sleet and thunder
Rain turns to drizzle or stops
Sometimes heavy rainfall
None at first , rain closer to front , some times snows
A warm front means warm air is coming . The warm air is less dense . At a warm front , warm air is rising over cold air . As the water vapour rises it cools and condenses , forming rain . You notice this because you get cirrus first , they thicken , grey nimbostratus , little drizzle of rain and then steady rain . It would get warmer and windier .
Warm sector – break in the rain because you’re now in the warm air , low air pressure
Cold front , cold air pushes under the warm air . you get cumulus clouds ,strong winds and heavy rain (slightly violent). The rain may stop and start again.
Depressions start in the west move over Britain west to east . its hard to predict their wind speed or direction because the front could speed up or slow down . You always get the warm front first .
Blue lines with triangles – cold front
Red lines with semicircles – warm front
Responses to global warming
Two types of response to climate change
* Adaptation – planning to reduce the damaging effects of global warming
* Mitigation – trying to slow down global warming by controlling greenhouse gases .
Adaptation examples:
* Building sea defences
* Develop drought proof strains of plants
* Improve water catchment and supply
Mitigation examples
* Afforestation (this is also considered as adaption)
* Use more renewable energy types
* Conserve energy
Evidence for climate change
Throughout the last few hundred years , temperatures have continued to fluctuate . During the medieval period (800-1400AD) the climate displayed a warming trend . Between 1550 and 1750 , there was a period of lower temperatures called the little ice age . These can be considered as a natural change . Since 1950 , there is evidence of a very steep increase in temperatures
Instrument readings
The global temperature is measured with a thermometer . In the last 100 years ,t eh global temperature went up and back down but generally increased by 0.74 – 0.5 degrees since 1980 . There could be other factors causing the weather to change like vegetation and volcanoes . As the temperatures increase the ice caps melt causing the sea to expand . We can see a general increase by 20cm by last century .
Glacier retreat
There is photographic evidence that the world’s glacier have been retreating . By 2050 , 25% of the global mountain ice could disappear . A reduction in snowfall and an increase melting are the causes of glacier retreat .
Artic ice cover
In the last 30 years , the artic ice has thinned to almost half its thickness . The albedo effect – as the ice continues to thin less solar radiation will be reflected back to space , Instead the sea will absorb more radiation , increasing temperatures further .
Ice cores
Water molecules and trapped air which ahs been built up the past few years will be analysed to detect change in temperatures . ice cores have been extracted from Greenland and Antarctica .
Early spring
In the last 30 years spring has been coming earlier . the evidence is that the birds are nesting earlier and bulbs (flowers) are flowering earlier
Depressions
‘Explain why the weather changes with the passage of a depression”
As the warm front passes , temperatures start to rise as the warm air takes over from cold air . Cloud increases – low level and thick and it begins to rain steadily as the rising air is cooled . As the warm sector passes , it is quite mild and rain becomes lighter as there is less uplift . As the cold front passes , temperatures fall and rain increases . Rain is heavier due to the cold air undercutting the warm air and causing rapid uplift . It is windiest as this time and the direction will change from SW to NW around the centre of the low .
‘describe and explain the global responses to the threat of climate change”
To try and reduce greenhouse gas emissions , 37 countries signed the Kyoto protocol . These countries must reduce their 1990 carbon emissions levels by 5.2% by 2012 . This is a step to reducing emissions worldwide where all counties need to take part as gases are not contained by political boundaries . Carbon credits aim to identity an overall amount of emissions by allowing countries to trade in amounts . Local strategies are also important as every little helps so turning off lights , using buses rather than cars will reduce our use of fossil fuels . Governments switching to wind power and introducing transport strategies such as congesting charging all play a part .
Responses to global warming
Gas – Carbon dioxide
Sources – burning fossil fuels , car exhausts , deforestation , burning wood
Individual responses – walking / cycling , conserving energy , paying a carbon offset , promoting public transport , congestion charging
National responses ; tougher MOT tests , congestion charge , filters in power stations , road tax
International responses : carbon credits , Kyoto protocol
Gas – methane
Sources – decaying organic matter in landfill sites and compost tips , rice farming , farm livestock , burning biomass for energy
Individual response’s – recycling , recycling for Hampshire
National responses – government promotion of recycling , waste reduction initiatives
International responses – discus at Earth’s summits , cattle farming , rice farms
Gas – nitrous oxides
Sources – car exhausts , power stations producing electricity , agricultural fertilisers , sewage treatment
Individual Reponses – walking , cycling , alternatives to fertilisers , organic food
National responses – filters in power stations , road tax , rules about chemicals in fertilisers and sewage works
International responses – Treaty signed tor educe GHG emissions
Extreme weather
Extreme weather – weather that is not what is expected normally . It occurs relatively rarely but may last longer than expected . It may break met office records . Examples of exceptional weather would be drought , heat waves , heavy snow , heavy rain , strong winds , storms , thick fog .
If there’s a flood coming to you , you can call Flood line . Met office , SEPA and environment agency flood warnings is updated regularly with incoming weather warnings . The highway agency is more for people on the road , there are specific websites for different places . Another one for the national rail . There is also one for airports.
Weathering Warning Guide
Red: extreme weather is expected , listen to emergency services as you are at risk . Avoid dangerous areas. Roofs may be blown off , phones could be overturned and power lines may fall down . There may be flying debris .
Amber : Interruptions to power , closed buildings , falling trees , tiles moving around on roofs and flying debris .
Yellow : small trees / branches may fall
During the storm – stay inside , don’t walk near other buildings and trees . Don’t try to repair damage during the storm , try not to drive .
After the storm – don’t touch any cables that have been blown over . Don’t walk near trees / buildings because the storm may have weakened them and they can fall on you . Try to help family and neighbours , see if they are okay .
Firstly in 2005 there was a flood in Carlisle , 3 people died , buses were damaged . Homes , schools and businesses were flooded . Appleby , cokermouth and Keswick also had flooding . this is the worse flood since 1822 . There was rainfall of 180mm (only rains this much every 200 years) . In January there was two major stormy spells . On the A1 it was reported that lorries were overturned . 80,000 people lost power in the NE . 20,000 homes were without power on the 2nd day . Most train services were closed because of the fallen trees , bridges and ferries were closed . 5 people died as they tried to drive through this . A deep depression which reached up to 962b and winds of 101mph . Now in June 2015 in North Yorkshire there was floods , within 30 mins there was 50mm of rain . Then in 2007 there was 150mm of rain in wales , in the Scottish highlands there was over 200mm . In May there was 385mm of rain in wales , the midlands , NE , northern Ireland , parts of Scotland and SE . In 2009 there was heavy snowfall in London , parts of Essex , Kent , surrey and Hampshire . Heathrow was closed and all London buses were stopped . In surrey there was 290mm of snow and 320mm in Hampshire . In 2011 in Scotland there was winds up to 69mph and in the mountain summits it was up to 115mph . In north wales , NE and Ireland there was winds up to 69mph. Many schools were closed and there was lots of power cuts. The trains were given a speed limit because of all the fallen trees. 150,000 homes lost power. In 2013 on the 5th December there was very stung winds in Scotland and NE which lead to a winter storm . 100,000 homes were left without power . In Glasgow , Edinburgh and Aberdeen the flights were cancelled , two people died , trees fell and traffic accidents occurred . Near the east coast of England several homes were flooded , thousands of residents were evacuated from their homes . This carried on through Christmas , 50,000 homes were without power then .
Case study – Atlantic storm
An Atlantic storm brought storm force winds to the Uk in December 2011 . A deep Atlantic low pressure system hit the north of England on 8th December . The strongest winds were in central , southern , north east Scotland , northern parts of Northern Ireland and NE.
Gusts of up ton 164mph were recorded on higher ground – the highest recorded gusts in the Uk since 1996 . At lower levels , wind speeds of 105mph were recorded at Twloch Bridge , while maximums of 77mph were recorded in Edinburgh during the rush hour and 71mph in Glasgow at lunchtime .
Met office action
5th December
* Issued a yellow alert for winds across the north
* They shared advice for the weather
* There was daily multi-agency response meetings
7th December
* Issued a red warning for strong winds across Scotland
* Issued red/amber alerts for areas of Scotland and the north of the uk
* A video forecast was spread so the public and emergency response community were well prepared .
Outcome – Everyone was prepared so people avoided potential damage . Schools were closed , reducing further disruption
Anticyclones
Anticyclones – an area of high atmospheric pressure , caused by air sinking towards the ground surface .
There are no clouds because the air sinks , the air needs to rise for clouds The air sinks and evaporates the moisture .
Characteristics – high pressure , hot and dry summer , cold and dry in winter . Cold air descends and warms up . Lasts for several days sometimes weeks . The wind moves clockwise in the northern hemisphere an anti clockwise in the southern hemisphere .
Summer – in both winter and summer the wind is the same , very calm and little wind . Very little precipitation because rain isn’t forming . Dry , hot and sunny . Early morning dew and mist . Heatwave conditions :thunder storms . The sun is strong . Water vapour condenses on grass to form dew .
Winter – its already and cold and clouds act as a blanket . If you don’t have clouds it is even colder , there a bigger impact in winter (losing 10 degrees) . In summer if you lost 10 degrees , it would still be warm . It’s dry , cold and bright . Early morning frost and fog . Low cloud and fog can last all day , causing gloomy conditions . Can cause icy roads and flooding from when burst pipes freeze .
Isobars show air pressure . They are lines on a weather map joining places of equal atmospheric pressure.
