Plate tectonics and associated hazards

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  • Created by: EmmaC
  • Created on: 23-04-16 15:37

Draw a diagram of the structure of the earth

(http://pubs.usgs.gov/gip/dynamic/graphics/FigS1-1.gif)Draw 

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Describe the core

The inner core is the centre of the earth and is made of solid Ni and Fe, which is being decayed radioactively to produce the heat and convection currents for the mantle. 

It is 5,100km to 6,37k5m deep and is over 6,000 degrees celcius. 

The outer core is semi molten and is 2,900km ro 5,100km deep

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Describe the mantle

The mantle surrounds the core and is make of silicate rocks, rich in iron and magnesium, apart from the more rigid upper mantle (asthenosphere) is semi-molten, with temperatures near the core reaching 5000 degrees celcius. 
These create the convection currents.

It is 100km to 2900km deep

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Describe the crust (lithosphere)

The crust of the eart is between 0-100km think being the thinnest part of the earth. 

There are two types of crust: oceanic and continental.

Oceanic:

  • younger ( less than 200 million years and still being made)
  • More dense at 3g/cm-3
  • Can sink and is destroyable
  • 5-9km think
  • Mainly basaltic called SiMa (silica and magesium)

Continental:

  • Older 1.5 billion years old
  • Less dense at 2.6g/cm-3
  • Floats on the mantle
  • 30-70km think(average) (maxi=100km min=60km)
  • Granite mainly called SiAl (silica and aluminum)
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What is the Moho discontinuity and the lithosphere

the Moho discontinuity is the boundary between the mantle and the crust on the earth. This is because this part is semi molten as is half crust, half mantle. Gradually becoming more molton.

The lithosphere is the crust of the earth

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What is the Moho discontinuity and the lithosphere

the Moho discontinuity is the boundary between the mantle and the crust on the earth. This is because this part is semi molten as is half crust, half mantle. Gradually becoming more molton.

The lithosphere is the crust of the earth

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Outline the history of plate tectonic theory

English philosopher Francis Bacon was aware of the shapes of S.America and Africa fitting together since the 1620's.

Topographical and geological evidence built up over the following centuries  allowed Alfred Wegner the geologist to publish a theory in 1912 suggesting that all the continents were once a supercontinent called pangea. He proposed that over time the land masses had drifted apart (continental drift) until they occupied the current postitions on the globe.

When pangaea broke up, the northern continents (N.America and Europe) seperated from the southern continets (Antarctica, S.America, Australia and Africa). The northern continent is Laurasia dn the southern is Gondwanaland

His theory collated the different pieces of evidnece that seemed to support the idea that continents were once joined. 

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What were the pieces of evidence for plate movemen

Continental -> Some continents (such as the western seaboard of Africa and the eastern seaboard of South America fit together is places next to each toher. This is particularly true if the continental shelves are taken into account as the true edges of the land masses.

Geological -> Rocks of the same ages and type displaying the same formations are found in SE Brazil and S Africa and trends of the mountains in Eastern USA and NW Europe are similar when they are placed in their old positions. SImilar glacial deposits are found in Antarctica, S.America and India which are now 1000s of miles apart and striations show the same orientations when the continents are reuninted, are found in Brazil and West Africa.

Climatological -> Antarctica, N.Amercia Svarlbard and the UK all have coal deposits of a similar age all formed in tropical conditions, they are no longer in tropical climate zones and must have drifted since the carboniferous period.

Biological evidence -> Similar fossil formations either side of the Atlantic such as the Mesosauraus in S.American and S.African sediments of the Permian age (280 mill years ago). Plant remains from swamps formed coal deposirs in India and Antarctica. Marsupials are found only in Australia because it drifted away from the main supercontinent before the predators that wiped them out elsewhere migrated there.

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What was correct and incorrect about Wegener's the

Wegener was unable to demonstrate a mechanism for continental drift, which, combined with his mostly circumstantial evidence, meant that his hypothesis was not accepted until the 1950s, when numerous discoveries provided evidence of continental drift.

The evidence he used, was correct, but without the mechanism is purely circumstantial. 

People tried arguing against his theories but suggesting the similar fossils were found, as the animals crossed 'land bridges'.

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Draw the map with the plate tectonics on

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Directions of some key boundaries

Constructive -> Eurasian and N.American plate moving apart  at 4cm per year

Destructive -> Nazca and S.American plate. Nazca moving 15cm per year but S.American only 10

Conservative -> Pacific plate and N.American plate (San Andreas Fault). The Pacific plate moves 7cm per year but the N.American at only 2.5cm

Destrucive -> Eurasiand and Indian plate -> Himalayas

                  -> Pacific and Phillipene plate -> Marianas trench

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How do plates move?

They move by convection currents. These are made by heat being released by the radioactive decay in the earths core. 

The circular motions of heat cause magama to rise towards the crust and then spread before cooling and sinking, this allows the plates to move.

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Explain the process of sea floor spreading and out

In 1948 a survery of the sea floor of teh Atlantic revealed a continuous ridge running north to south. It was 1000km wide reaching 2.5km heights and composed of volcanic rocks. Magnetic surverys in the 1950's showed the regular patterns of palaeomagnetic striping about the ridges. 

When the lavas erupt on the ocean floor, the magnetic domains within the iron rich minerals in the lava aligned with the magnetic field of the earth. This is fixed as the lavas cool. Recording the earths polarity as they do. As teh earths polarity reverses roughly every 400,000 years bands or stripes of normal and reverse polarity rocks are mirrored either side ot the mid-ocean ridges, suggesting rocks are added evenly on both sides

Surverys revealed that the rocks on or near the rocks were very young (Iceland less than 1 million) and much older near continental masses such(200 million). The old crust is geting pushed aside by the younger rocks. There is no evidence for the earth growing however. This lead to the discovery of trenches where large areas of ocean floor are being subducted, such as around the fringes of the Pacific ocean. Subduction provided the mechanism for sea floor spreading and drifting of continents. This explains why continental crust is more complex and has older rocks. 

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Explain the features of a constructive margin

A constructive margin occours when two plates move apart. The mantle is udner pressure from the plates above and as they more apart the pressure is released at the margin. The release of pressure caused the mantle to melt to create magma. 

The magma is less dense than the plate above so can rise to form a volcano.

As the plates don't move apart uniformly, pressure builds up to form fault lines and creating EQ. 

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Formation of mid-ocean ridges

Where constructive plates are underwater a mid ocean ridge forms. Such as the mid-atlantic ridge with the Eutrasion and North American plate.

Underwater volcanoes also erupt along mid ocean ridges and they can build up above sea level such as Iceland along the Mid-Atlantic ridge

There precise form appears to be influenced by the rate at which the plates seperate:

-A Slow rate - (10-15mm per year) as seen in parts of the Mid-Atlantic ridge produces a wide ridge axis (30-50km) and a deep (3000m) central rift valley with inwards-facing fault scarps

- An intermediate rate - (50-90mm per year) such as that on the Galapagos ridge (Pacific) produces a less well marked rift (50-200m deep) with a smoother outline

- A rapid rate (>90mm per year) such as on the east Pacifi rise, produces a smooth crest and no rift

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Formation of Rift valleys

Where plates seperate beneath the landrising magma causes the continental crust to bulge nad fracture forming fault lines. 

As the plates keep moving apart, the crust between the parallel faults drops down to form a rift valley. Such as the East African Rift System is a series of rift valleys that stretches from Mozambique to the Red Sea (about 400km) 

Formed due to the Nubian and SOmalian plates seperating.

Volcanoes are found aroung the rift valleyes cuh as Mount Kenya and Mount Kilimanjaro. 

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Diagram of mid-ocean ridges

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Diagram of rift valleys

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Explain the features of a destructive margin

Two plates are moving towards each other. What happens at the plate depends on the types of plates converging.

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Describe the formation of features at oceanic-cont

Continental and oceanic convegre, the more dense oceanic crust is forced under the less dense continental crust (subducted), forming a deep sea trench. Such as the peru chile trench in the Pacific ocean.

Fold mountains also form, thy're made of sediments that have accumulated on the continental crust, which are folded upwards along the edge of the continental crust. 

The oceanic crust is heated by the friction and contact with the upper mantle which melts into magma. The magma is less dense than the continental crust and so will rise back to the surface to form a volcano.

As one plate moves under the other they can get stuck, causing pressure to build up. When the pressure becomes too much the plates jerk past each other causing an EQ

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Draw a diagram showing all land formations created

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Describe the features found at oceanic-oceanic col

Most of the same processes occour as continental-continental. 

Volcanic eruptions that also take place underwater (two oceanic plates converge) to create island arcs, these are clusters of islands that sit in a curved line such as the Mariana Islands.

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Describe the features found at continental-contine

Two plates move towards each other neither is subducted and they're aren't any volcanoes but the pressure thay builds up between them can cause EQ

Fold mountains form when continental crusts converge such as the Himalayas

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Describe the features found at conservative margin

Plates pass each other.

The two plates may get locked together and causes pressure to build up, this causes the plates to jerk past each other creating fault lines and causing EQ

The pacific plate and the North American plate show this with the San Andreas fault in Californica

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Describe the features found at conservative margin

Plates pass each other.

The two plates may get locked together and causes pressure to build up, this causes the plates to jerk past each other creating fault lines and causing EQ

The pacific plate and the North American plate show this with the San Andreas fault in Californica

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Explain the presence of Hotspots?

A concentration of radioactive elements inside the mantle may cause a hot spot to develop. From this a stationary plume of magma develops which eats into the plate above. 

Where the lava breaks through to the surface active volcanoes occur above the hotspot. 

In the middle of the Pacifc plate a string of hotpot volcanoes are formed. These are the Hawaiian islands. As the pacific plate moves over it, a line of extinct volcanoes are formed.
Some of the islands become eroded by waves and form flat topped sea mounts called guyots.

The pacific plate moves NW at 10cm/year. 

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Diagram of Hawaiian islands

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Features of fissure volcanoes?

Elongated criacks in crust allow lave to spill out over a large area. Around spreading ridges were tension pulls the crust apart.

Such as Eurasian and N.American plate causing Heimacey Iceland to erupt in 1973.

Rock Type: Basaltic

Location: Contructive margins and rifts

Eruption type: Gentle and persistent

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Diagram of a fissure volcano

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Features of a shield volcano?

Basaltic rock and form gently sloping cones of less viscous lava e.g Mauna Loa Hawaii

Rock type: Basaltic

Locations: Oceanic crust meets oceanic crust

Eruptions: Gentle and predictable

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Diagram of a shield volcano

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Features of composite volcanoes?

Most common type in the world, created from layers of ash from inital explosive phases of eruption. Such as Mount Etna

Rock type: Andesitic

Location: Destructive margins

Eruptions: Explosive, unpredictable 

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Diagram of a composite volcano

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Features of acid/dome volcanoes?

Steep sided from viscous lava, creates convex cone-shaped volcanoes. Lava can solidify in the vent and later be exposed by erosion.

Rock Type: Rhylotic

Location: Continental crust

Eruptions: Explosive and unpredictable

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Diagram of acid/dome volcano

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Features of Calderas?

Form when gases that have built up beneath a blocked volcanic vent result in a catastrophic eruption that destroys the volcanic summit, leaving an enormous crater where later eruptions may form smaller cones.

In the case if the crater lake in the US, the Caldera has filled with water.

Rock Type: Andesitic

Location: Destructive Margin

Eruptions: Very explosive, unpredictable

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Diagram of a caldera

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The nature of volcanic eruptions

Vulcanologists have traditionally classifies volcanoes according to the nature of the eruption. This is based in the degree of violence of the explosion which is a consequence of the pressure and amount of gas in the magma.

The least explosive:    Basaltic:

  • Icelandic
  • Hawaiian
  • Vesuvian                Andesitic:
  • Krakatoan
  • Pelean                   Rhyolitic:
  • Plinean

The most explosive:               

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What are the different types of lava and where are

Andesitic and Rhyolitic - Silica rich magma that is very viscous. This often solidifies before reaching the surface leading to a build up of pressure and a violent explosion.

Basaltic - Magma low in silica. More fluid magma that allows gas bubbles to expand on the way up to the surface preventing sudden explosive activity.

Aa lava - Rhyolitic and andesitic so is slow moving and think.

Pahoehoe (Hawaii) - Basaltic, thin so runs easily and spreads into sheets

Pillow- underwater, sac like blocks. Quick to cool, cystalline structure

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Primary hazards

  • Lava flows 
  • Pyroclastic flows - Very hot (800 degrees), gas charge, high velocity flows made up of gases and tephra
  • Gases - CO, CO2, H2S, SO2, Cl, HCl. Emissions of CO2 from Lake Nyos in Cameroon in 1986 suffocated 1,700 people
  • Tephra - Solid material varying from grain size, to volcanic bombs. Usually is ash and is ejected into the atmosphere
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Secondary Hazards

  • Lahars - Volcanic mud flows such as those that devestated the Colombian town of Armero after the eruption of Nevado del Ruiz in Novemeber 1985
  • Flooding - melting glaciers and ice caps such as Grimsvotn glacial burst on Iceland in November1996
  • Tsunamis - Giant sea waves generated after violent caldera forming events such as Krakatoa in 1883 the tsunamis from this eruption have drowned 36,000 people
  • Volcanic landslides 
  • Climate change - The ejection of vast amounts of volcanic debris into the atmosphere can reduce global temperatures and cause acid rain
  • Ecosystem impacts
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Positive impacts of volcanic activity

  • Tourism
  • Agriculture
  • Geothermal Energy
  • Minerals
  • Island creation from lava
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What are boiling mud and hot springs?

Sometimes the water heated below does not explode onto the surface. If the water mixes with surface deposits, boiling mud is formed. Such features are very common in Iceland. Hot springs in Bath in West of England. 

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What are solfatara?

Small volcanic areas without cones, produced by gas (mainly sulphurous) escaping the surface, for example the bay of Naples in Italy.

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What are geysers?

These occour when water, heated by volcanic activity, exploded onto the surface such as Olf Faithful in Yellowstone.

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What are fumeroles?

They are areas where superheated water turns into steam as it condenses on the surface. These features are typical of areas such as Solfatara in Italy where the escape of steam and water mixed with sulphur-rich gases gives rise to the collective name for these features of solfatara

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What is a batholith, a sill, and a dyke?

The majority of magama never reaches the surface but cools to forms igeneous rocks beneath the ground.

These rocks make contribute to surface geomorphology through erosion.

Batholiths forms when large masses of magma cool very slowly, producing coarse grained rocks, such as the granites uner the Lake District.

Where magma has been squeezed between existing strat it may form a sill (horizontal) or a dyke (Vertical). The Whin sill stretches from Dufton in N.Yorkshire to Holy Island in Northumberland. The erosion of the surrouding rocks can leave dykes exposed as low ridges, as at Kildonan on the Isle of Arran in Scotland. 

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Draw the major intrusive features

(http://www.acegeography.com/uploads/1/8/6/4/18647856/1617860_orig.jpg)

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Explain the cause of EQ at plate margins and intra

EQ are caused by a build up of pressure within the earths crust which is suddenly released causeing the ground to shake violently. 

The point within the crust where the pressure release occours is called the focus and can be at a range of depths:

Shallow - 0-70km

Intermediate - 70-300km

Deep -300-700km

The seismic waves have their highest level of energy at the focus, energy decreases as the waves spread out. The place on the earths surface abouve the focus is the epicentre. It recieves the most energy so is potentially hazardous.

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Describe the different types of seismic waves

P Waves are the fastest and shake the earth backwards and forwards. These travel fastest and move through solids and liquids

S Waves are the slower and move with a sidways motion, shaking the earth at right angles to the direction of travel. They cannot move through liquids but do much more damage than Pwaves

Surface Waves - Travel near the surface and more slowly than P or S waves but are more destructive than both. They include L waves (long) which cause the ground to move sidewaysand Raleigh waves which make it move up and down.

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How does the richter scale and Mercalli scale work

Magnitude is amount of energy released by event, measured by richter scale. This is a logarithmic scale, with each unit representing a 10 fold increase in strength and a 30 fold increase in energy released.

The intensity of an EQ is meaured by a 12 point mercalli scale.

The moment magnitude scale is also used  it: "The moment magnitude includes the area of the fault's rupture and slippage along the fault. It also includes the size of the seismic waves recorded by seismographs on seismograms"

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Effects of EQ

Tsuanami - Sea waves generated by disturbances on the sea floor. 

Liquefaction - Violent disruption of ground causes it to become liquid like when shaken.  San Fransisco US$100,000 damages in 1989 EQ

Landslides and avalanches - due to slope failure

Human Impacs - Population density and distance from the epicentre, disrupt gas and electricity. Buildings and infrastructure may collapse. Fires. Contamination, disease. 

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EQ management

Prediction - not reliable: 

Seismic records - Study patterns helps predict next one. Recorded on seismograph.

Radon Gas emissions - Inert gas that is released from rocks such as granite at a faster rate when fractured by deformation. 

Ground water - deformation of ground can cause water levels to rise or fall independantly of atmospheric conditions. 

Remote sensing - Some evidence that electromagnetic disturbances in the atmosphere above the areas to have an EQ detected. 

Low frequency Electromagnetic activty - A sudden change in inospheric electron densiy and temp happens before EQ such as Japan Sept 2004 7.1M EQ.

Protection - Evacuation plans, Education, buildings resistence such as deep foundations or pendulum bearings, Land use plannings

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Features of a tsunami?

Caused by the movement of energy through water from energy underwater rather than wind.

Energy rised through water displacing it above sea level, gravity then pulls it down, causing the energy to ripple outwards horizontally.

Waves can be created moving at 500mph plus.

When the wave reaches shallow water, wave shoalling occours as less water is available for the water to move through and so the massive amount of energy is compressed. Causing wave speed to slow, yet wave height rises to 100ft.

Called a habour wave as occours near the coast. Water will withdraw before the wave hits.

After the wave has hit, it will retreat taking debris with it. 

Sea wall, flood defences and channels created to reduce impact however not always effective such as the 2011 Japanese EQ the waver went over the sea walls into Fukishima causing a nuclear disaster.

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MEDC EQ - Etna - Location and background

  • Highest (3,310m) active volcanoes in Europe, 5000 year history 
  • 25% population live on slopes
  • Decade volcano
  • 60 flank eruptions and many summit eruptions since AD1600
  • Since 2001, erutptions every year
  • Well monitered
  • Destructive plate margin on a subduction zone of Africa under Eurasian
  • Magma to rise to surface through weaknesses in crust
  • On the Isle of Sicily near Italy and is easy to monitor as no montain range in the way.
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MEDC EQ - Etna - Nature of hazard

  • Fertile soil =agricultural land
  • Minor explosive eruptions
  • Composite -> Basaltic lava (typically andesitic) 
  • Fissure open to release lava flows from a variety of locations and parastic cones open also
  • Seismicity -> Buildings and infrastructure around volcano effected
  • Gas, Volcanic dust and ash -> High explosive events at craters lead to eruptive columns of ash. Issues to settlments, agriculture and traffic.
  • Flank collpase -> Avalanche of volcanic debris
  • Phreatic eruptions -> Steam driven, water beneath ground is heated causing steam, water, ash and lava bombs.
  • 16992 - Lava headed to Zafferana -> howver was successfuly redirected by explosives
  • 2002/3 - Huge ash column deposited in Libiya 600km across Mediteranen sea and the eastern flanks slipped by 2m damaging houses
  • 2006 - Ash emissions on east side
  • May 2008 - New fissure opening and lava flow down 6km of the Valle Del Bove
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MEDC EQ - Etna - Impacts

  • 77 deaths due to eruptions, mainly tourists off pathways
  • 2002 eruption destroyed tourist station at Piano Provenzana and Rifugio Sapienza
  • 29 July 2002, Catania airport closed to clear ash from runway affecting tourism
  • Ash fall on Catania and libya
  • Catania closed for 4 days
  • Magma 100m in the air and ran quickly down the mountain and residential areas such as Ling Vaglossa. Evacuation of 1000 people
  • Skiing areas damaged by lava flow, resturants destroyed and ski lifts pushed over and 1000s of ha of forest destroyed
  • 300 family businesses affected and ski schools closed for years so people left the island to find work
  • 4 September 2007 an eruption on the SE crater caused lava to go 400m into the air and strong winds sent ash and smoke to towns below
  • Roads destroyed
  • Farms covered in ash and crops planted were lost, loss of money
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MEDC EQ - Etna - Responses to the events

  • Rescue workers tried diverting lava as it threatened a scientific monitering centre as the base of the volcano. They did this by using explosions and dropping chunks of concrete to act as walls for diversion
  • Bulldozers used to crack tarmac in car parks to channel lava away from residential areas such as Linguaglossa
  • Ship with medical clinic near Catania is needed
  • Tax breaks given to the affected
  • £5.6 million immediate financial assistance
  • Italian army heavy earth moving equiptment used to divert flows
  • Most people rebuild own houses from sallvaged material, little government intervention. 
  • 2002 eruptions of soil and volcanic rock put up to protect tourists base at Rifugio Sapienza to divert flow
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MEDC EQ - Etna - Management of event

  • Catania section of Instituto Nazionale Di Geofisica e Vulcanolgia (INGV) monitored the volcano for 20 years, using a permenant network of remote sensors connected in real time to aquisition centre in Cantania
  • Data continuously recorded by permanant stations are integrated to evaluate the activity level of the volcano and to issue warnings
  • Geochemical monitoring programme test gas and fluid emissions and predict new eruptions and to warn of dangerous gas emissions such as an SO2 plume be measured by spectrometry.
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LEDC EQ - Chaiten - Location and background

  • Friday 22nd May 2008 in SE 
  • Nazca and S.American plate -> subduction -> Benioff zone
  • Oceanic and continental convergence
  • 150km east of Peru-Chile trench
  • Chaiten town is situated 10km SW of the volcano and was covered in ash
  • A low subduction angle explained the lack of volcanic activity
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LEDC EQ - Chaiten - Nature of Hazard

  • Rhyolitic lava from the composite volcano
  • Numerous plumes, pyroclastic flow, EQ and lahars
  • Ash cloud 17km high
  • Plinian eruption
  • VEI of 4 from 0-7
  • Lava eruptions by late May created a new dome of 540,000m2 containing 55million3 of material
  • The collpase of the eruption column brought more ash down, causing asphyxiation of animals and blocked roads
  • Caused thunderstorms, heavy rains, ash and flooding
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LEDC EQ - Chaiten - Impact

  • Chaiten had lahars and ash causing disruption of travel and agriculture in other countries
  • 4000 people evacuated by boat
  • Futaleufu had 1000 residents evacuated
  • Smaller communities such as Chubut and Rio Negro had heavy ashfall
  • Ash plume so thick that schools, highways and an airport in Argentina close which is 2,300km away
  • 5 planes has engine damage
  • Health problems in Chile and Argentina
  • International and home flights cancelled
  • Lahars are 15cm deep and cut communication and become contaminated due to water supplies
  • 90% Chaiten closed due to rivers
  • 1 death by stress
  • 80-90% of Chaiten damaged and 20-30% destroyed. The damages was extensive to airport and marine facillities
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LEDC EQ - Chaiten -Management and responses

  • 5000 people evacuated from nearby towns
  • Chilean gov made a comlete evacuation of town and planning to relocate town
  • Chilean Navy evacuated 3,900 people
  • They also told the residents not to drink the water and were given fresh water and face masks. 
  • There was a 50km exclusion around the town
  • $1200 and $2200 per month per family as a stripend
  • Financial aid was given to small businesses, there was a 90 day freeze on payment of existing loans on state bank, Banco Estado
  • Seismic monitoring began on 16 May 2008 by the USGS (not a home agency)
  • Chiles geological survey created a new programme to monitor 43 of Chiles high threat volcanoes.
  • Before the eruption there was no monitoring because of how long the volcano was dormant for and becuase of the low population density so not a priority
  • Only 20 volcanoes with completed risk assesment studies and full histories out of 200
  • A huge development was the volcano disaster assistance programme (VDAP) to aid prediction on subsequence eruptions
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LEDC EQ - Chaiten - Vulnerability

  • Low pop density- Limits the potential impacts to humans on a local scale
  • The country is nationally vulnervale to EQ and volcanic events due to location on subduction zone
  • Andes have 40 active volanoes and 200 in total
  • Regular storms and ash making lahars and causing flooding
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LEDC EQ - Chaiten - Capacity to cope

  • Only 20 volcanoes with geological studies
  • Chaiten was low threat but even wihour rating there was no observatory in Chile which effects the prediction of events
  • Low pop density and dormant makes it not a priority for explosive past
  • Eruption was not monitored until USGS moved in 15 days after the eruptions
  • Prediction and preperation of hazard was poor
  • However chile has an armed service which was intrumental to the aid of the region.
  • Stable democratic government
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Gujarat EQ - Location and background

  • West India, 26th Jan 2001, centred (focus) in the small town of Bhuj, Gujarat. Only 197km from the Pakistani border making this an international event
  • 7.9 richter scale
  • 17km deep focus
  • One of the most powerful EQ felt in India in the last 100 years and therefore the effects were felt on the far eastern side of India and in adjoining countries such as Nepal and Bangladesh
  • India is developing country which has frequent EQ that last being only 2 years before so the rebuilding of EQ proof buildings is costly to the country and also time bound
  • The EQ caused due to conservative plate movement between the Indo-Australian plate and the Eurasian plate.
  • Minimal pre-planning in the are and little agreement on EQ policies due to many seperate small villages making up the population. 
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Gujarat EQ - Impacts

  • Short term:
  • Over 1 million people were made homeless due to the weak nature of the buildings
  • More than 160,000 people were seriously injured meaning specialised treatment in a specialised centre is required
  • 4 hospitals were destroyed in Bhuj therefore making it very difficult to treat the immediately injured e.g. excessive bleeding. They had to be brought in from exterior sources
  • Approx 345,000 dwellings were destroyed and 800,000 suffered from some damage leaving some homeless striaght away and some businesses abandoned. 
  • Long term:
  • The death toll was between 15 and 20,000. No accurate measure could be calculated until days after the EQ as the authoritites were unable to cope with magnitude and so families left devesated for years to come
  • Much cultural heritage destroyed including palaces and temples, hindering tourism
  • Communications severely disrupted and weak power lines brought down making external phone calls hard to make
  • Immediate loss of 20,000 cattle ment a sustained loss of agriculture, major impact as the agriculture was significant to economy of the area.
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Gujarat EQ - Responses

  • Short term:
  • A section of the population commited to widepread looting occuping the authorities for 5 days
  • Rescue teams were sent into release the people trapped beneath fallen buildings
  • The indian government sent 5000 troopede into the area alongside 40 military aircraft, maily helicopters and three navy vessels with full functioning hospitals each capable of coping 200 patients
  • Trained military personal transported medical aid, food, tents and communication equiptment immediatley to the worst effected areas such as Anjar
  • Long term:
  • Many of the present population suffered from widespread epidemics like Typhoid and Cholera following the event for weeks after due to sewage works being damaged. Aided vaccinations meant these didn't surface too much but diarrhoea and gastroenteritis were reported more seriously
  • It was suggested that within a month 1 million people benefited from some variety of aid - Britain sent 70 teams of international development members to help with resuce operations.
  • Mass disinfectant was spreayed to prevent the spreading of disease weeks after due to buried rotting bodies.
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Gujarat EQ - Management

  • 99% of houses repaired and 90% of houses reconstructed
  • 100% schools repaired and 50% extra schools made
  • 5,500km of transmission and distribution lines repaired
  • Restored the livlihoods of 2,000,000 familes.
  • Houses were upgraded and community buildings such as hospitals upgraded
  • Education so 80% knew what to do in case of disaster in comparision to 6% before
  • Employment among women rose by 50%
  • The quality of life index rose from 1% to 1.143%
  • The rebuilding was completed by the Gujarat relief manual and their template for tebuilding has now been adopted by diaster zones such as Bam and Sri Lanka.
  • Massive information education and activity undertaen to educate people on multi-hazard resistant construction.
  • Over one million pamphlets on safe housing repair and reconstruction distributed in EQ affected areas. These were also local village communities completed to train locals about EQ evacuation. 
  • Local newspapers also posted up-to-date methodologies in the area.
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Indonesian Tsunami - Intro

  • Struck on the west coast of Sumatra on 26th December
  • Submarine EQ measured 9.1-9.3 on the richter scale and reached the highest intensity of destruction on the mercalli scale.
  • The EQ triggered a huge displacement of water, Indonesia was the hardest hit country followed soon by Sri Lanka and Thailand

(http://www.coolgeography.co.uk/GCSE/AQA/Restless%20Earth/Tsunamis/tsunami%20map.gif)

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Indonesian Tsunami - What happened and why?

  • Result of the Indo-Australian plate subducting below the Eurasian plate 
  • It was a moment magtiude of 9.1-9.3 EQ.
  • The epicentre of the EQ happened just off the west coast of Sumatra, an Indonesian island. This was 12 on the Mercalli scale. 
  • The EQ caused a series of tsunamis at 1am UTC, it was the third largest EQ every recorded by a seismograph and the longest duration of faulting lasting 8.3 minutes.
  • They caused EQ to trigger as far away as Alaska
  • The tsunami waves travelled speeds up to 800km per hour, making it very difficult to carry out an adequate warning system.
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Indonesian Tsunami - Impacts 1

  • Inital wave killed 150,000 people yet the final death toll was nearer 300,000 due to those dyying from lack of medical care and their injuries.
  • 1.7 million people homeless, displacing people in countries as far as Somalia.
  • 5.6 million left needing medical aid and fresh water. Threat of disease long term due to the mixing of salt and fresh water. The tsunami had destroyed sewage works increasing the spread of disease such as Typhoid and Cholera and Dysentry. 
  • As many of the countries effected were LEDC's meanign governments were less able to send out aid and relied on international aid more, yet it took longer to arrive. 
  • Sumatra one of the first effected and witnessed a 30m wave an the initial wave destoyed over 1,500 villages in the north of the area
  • Long term implications as issues over how to fund rebuilding infrastructure.
  • Pushed the gov to think about planning for natural disasters and introduce management strategies.
  • Aceh island had huge conflicts with gov forces however tsunami caused peace to return
  • The port in Meulaboh was completely destroyed and an Indonesian Navy ship had to turn around as it was unable to dock and bring in supplies. In addition the Port of Tanjung Priok in North Jakarta was out of access for 1 month. It handles 50% of imports and exports
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Indonesian Tsunami - Impacts 2

  • Estimated 60% of the fishing fleet was destrpyed - 3% of GDP in Indonesia and took 6 years for the fishing industry to recover in the islands. This effet economically but also socially as a huge part of the diet was fish and so more aid was needed to sustain the diets.
  • Structural damage costing billions of dollars to rebuild. Loss of tourism profits. Foregin visitors the year after to Phuket fell by 80% in 2005.
  • Destroyed communication routes, making getting the aid also hard as airports weren't safe to land at. 
  • Immediately destroyed 116,000 acres of land, swamping them with salt water, making it uncultivable as few plants can exist in saline conditions.  It took over 10 years for the area to become suitably alkaline enough to farm. 
  • Mangrove along coast destroyed, important ecosystems for a large variety of marine animals. Also stabilise coastlines preventing erosion from storms and waves, causing the rapid erosion of the coastline since 2004. 
  • 20,000 people in Thailand diagnosed with PTSD
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Indonesian Tsunami - Responses

  • Most individuals run for higher grounf after seeing water retreat however as tsunamis hit many LEDCs they didn't understand the drawback due to insufficent education
  • Re-established buildings and businesses to bring back the community feel
  • Many migrated out of the area over 433,000 from affected cuntries migrate to Canada in 2005
  • NGO's also played a huge role, within an hour Sri Lanka actionaid sent in food aid. And Actionaid in the UK raised £13 million in the first week
  • Helped to rebuild infrastructure and offer psychological conunciling to those who needed it. 
  • Another NGO (food and agriculture organisation of the UN)  who trained 140 boat builders and supplies 200 boats to the area so that the fishermen could start to rebuild the economy
  • Thai and Indonesidan gov sent a warning to Africa which saves many lives
  • Slow reaction due to limited resources
  • India managed to send navel ships within hours to effected areas
  • WHO also warned that thyphoid and cholera could prove fatal.
  • A long term response was the UK and France sending a team of medics to provide medical care and purification tablets
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Indonesian Tsunami - Responses 2

  • DEC EQ fund set up on the 27th and recieved £32 million in donations
  • Introduction of the early warning systems in the Indian Ocean as an international response sends all data to all Pacific countries
  • Small scale sustainable development projects to aid recovery and helps locals rebuild their lives.
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Indonesian Tsunami - Management

  • Prediction
  • No warning systems before 2004
  • The Thai authrorities recieved news of the tsunami but failed to issue a warning as had no idea about potential samage of magnitude
  • Failure to predict the wave unveiled in 2005 and made fully functional in 2008 warnign system. 
  • Use 39 detection buoys worldwide sends signals if experience any suddent movement due to release of plate energy
  • Protection
  • Little resources to spend on protecting are for 'What if?' scenerios
  • LEDC dont have the acedemic know how to know how to protect areas
  • Government after 2004 did some land use planning and re-built houses on higher land
  • The green coast project was a 5 mill euro project to protect rebuilt areas from future wave. Re-planting Mangroves in the shallow waters, they had been cut down from the Gle Jong coastline as ruined the beaches for the tourists. These slow down force of water from future waves.
  • The project focuses on sustainable methods of tsunami protection in the area.
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Indonesian Tsunami - Management 2

  • Preparation
  • WHO provided over 200 leading experts in tsunamis and post disaster care to provide resources for any future disasters
  • Sri Lanka 86% of school children recieved training on how to deal with future tsunamis
  • Early warning systems
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