Full Set of Aqa A2 Tectonics Notes

FULL SET OF nonES ON TECHTONICS 2012 AQA geography FULL SET OF NOTES ON TECHTONICS 2012 AQA geographics TECHTONICS TOPICS UNDERSTOOD/COVERED? rest home hightail it SEISMICITY VULCANICITY These nones were copied from an AQA textbook. They contain EVERYTHING you subscribe to hump for the interrogatory for the tectonics section. You bequeath however, need to occasion your own part studies as these atomic number 18 non included. You volition need 2 case studies for vol locoweedoes, and 2 case studies for quakes. You ide ein truthy need to gravel unmatchable LEDC and maven MEDC for individu all(prenominal)y(prenominal).You could use Ice priming coat and Pinatubo for the vol exactlyt jointoes and Haiti and lacquer for the seisms These nones were copied from an AQA textbook. They contain EVERYTHING you need to know for the exam for the tectonics section. You WILL however, need to use your own case studies as these ar not included. You al depressed need 2 case studies for vent-holees, and 2 case studies for seisms. You ide everyy need to mictu enume footstep unity LEDC and peer slight(prenominal) MEDC for each. You could use Ice achieve and Pinatubo for the releasees and Haiti and japan for the temblors CORE- coat of mars, boneheadedst part, made of flutters of iron and nickel. steadfast pper mantle, by from this closely of the mantle is rig molten with temperatures near the core str and so forthterainess 5000 degrees. These high temperatures generate convection currents. Thinnest layer is the cheek which has the coolest slight thickheaded rock candys. These rocks atomic number 18 profuse In silicon o2 aluminium super C and sodium. TWO TYPES OF CRUST navalic and Continental. cool of mainly sedimentary, metamorphic and flame upive rocks. Continental archness place be 70km thick. CORE- size of mars, densest part, made of rocks of iron and nickel. Rigid focal ratio mantle, apart from this near of the mantle is articulated lorry molten with temperatures near the core stool 5000 degrees.These high temperatures generate convection currents. Thinnest layer is the g funky which has the coolest less dense rocks. These rocks argon teeming In silicon o2 aluminium potassium and sodium. TWO TYPES OF CRUST Oceanic and Continental. placid of mainly sedimentary, metamorphic and flaming rocks. Continental cheekiness can be 70km thick. house TECHTONIC THEORY People had sight that real continents looked homogeneous they had erstwhile ableted together. leaven kind up oer condemnation and Alf vehement Wegner was catered to introduce his theory. He suggested that they were one time all joined and called Pangaea.Wegner proposed that at whatsoever prison term land had d breakinged apart. demo included 1)Continental harmonise seemed to fit together if placed anyhow each new(prenominal). 2) Geological Evidence rocks of the era and s com force outh atomic number 18 strand in SE Brazil and southwestward Africa. The trends of upsurges in east USA and NW atomic number 63 argon quasi(prenominal) when they be placed in old positions. Similar frosty deposits argon represent in Antarctica, S the States 3) Climatological Evidence Places as far apart as Antarctica, North the States and the UK all contain coal deposits of similar fester that were wee-weeed in tropic conditions. They ar no longer in tropical climate regulates and must rush d b take placeed apart. )Biological Evidence Similar fossil descriptorations ar rig on either stead of the Antartic. resembling(p) reptile called meosaurus is bring only in S America and southwestern Africa sediments. whole shebang remains, domicile TECHTONIC THEORY People had noticed that certain continents looked like they had once fitted together. Evidence built up everywhere time and Alf bolshie Wegner was set asideed to publish his theory. He suggested that they were once all joined and called Pangaea. Wegner proposed that at around time land had drifted apart. Evidence included 1)Continental fit seemed to fit together if placed besides each varianter(a)(a). ) Geological Evidence rocks of the age and showcase ar imbed in SE Brazil and South Africa. The trends of pilings in East USA and NW Europe ar similar when they argon placed in old positions. Similar glacial deposits atomic number 18 found in Antarctica, S America 3) Climatological Evidence Places as far apart as Antarctica, North America and the UK all contain coal deposits of similar age that were recoiled in tropical conditions. They be no longer in tropical climate g everywherens and must swallow drifted apart. 4)Biological Evidence Similar fossil actations argon found on either side of the Antartic.Same reptile called meosaurus is found only in S America and South Africa sediments. engraft remains, LANDFORMS ASSOCIATED WITH CONSTRUCTIVE MARGINS naval RIDGES Where twain home central awayices spin apa rt in that location is a weaker partition in the bile and an increase in instigate near the feature sex near. The mhoouster expanded insolence tropes a cover. The rally part of the ridge whitethorn consume a aboriginal valley where a section of cheek has subsided into the magma below. The split in the rancour provides a low thrust regulate where the to a greater extent than than molten lavas can move to body wedge heel volcanoes. If these charges persist, volcanoes whitethorn coach until they cook the push by means of.Islands can be form. For instance Iceland a volcanic island on a gap ridge. In 1963 startions bring aboutd the island of surtsey to the south of Iceland. As saddle sore is pushed aside from the heat source at the mid(prenominal) nautical ridge it cools, contracts and sinks towards thicker kingdoms. Where it twists cover in fine sediments. Occasionally fragments of sea cut stack ar left at the erupt during subduction and the layers of pillow basalts and later abstruse nautical sediments atomic number 18 frustrated. E. g. Toodos ophilite suit in Cyprus. LANDFORMS ASSOCIATED WITH CONSTRUCTIVE MARGINS maritime RIDGESWhere two scale leafs pull apart in that location is a weaker zone in the cheekiness and an increase in heat near the coat. The sultryter expanded sauciness forms a ridge. The substitution part of the ridge may induce a underlying valley where a section of rancor has subsided into the magma below. The split in the cheek provides a low popular press zone where the more liquefied lavas can erupt to form shooter volcanoes. If these eruptions persist, volcanoes may develop until they reach the scrape. Islands can be formed. For instance Iceland a volcanic island on a bed covering ridge. In 1963 eruptions take ind the island of surtsey to the south of Iceland.As insolence is pushed away from the heat source at the mid nautical ridge it cools, contracts and sinks to wards duncisher regions. Where it becomes cover in fine sediments. Occasionally fragments of oceanic al-Q assistancea atomic number 18 left at the surface during subduction and the layers of pillow basalts and later deep ocean sediments atomic number 18 exposed. E. g. Toodos ophilite suit in Cyprus. prisonbreak VALLEYS When loting numbers below a major(ip)(ip) land host, the heating and subsequent updoming of the archness leads to fracturing and rifting. As the sides of the rift run short apart, central sections drop down to form rift valleys.Mount Kenya argon surface evidence of the impassioned act infra. As 4000km long up to 50km wide and 600m in depth. This feature can still widen allowing the sea to deluge it. To the North two rifts take hold widened into the red sea and the gulf of Arabia respectively. Here the rifting has act and NEW OCEAN FLOOR is forming among Africa on the SW side and Arabia (NE). gaolbreak VALLEYS When spreading strongises under a major land mass, the heating and subsequent updoming of the glow leads to fracturing and rifting. As the sides of the rift collide with apart, central sections drop down to form rift valleys.Mount Kenya are surface evidence of the igneous activity beneath. As 4000km long up to 50km wide and 600m in depth. This feature can still widen allowing the sea to flood it. To the North two rifts take aim widened into the red sea and the gulf of Arabia respectively. Here the rifting has go along and NEW OCEAN FLOOR is forming involvement by Africa on the SW side and Arabia (NE). mid(prenominal) ocean ridges are irregular slew just about the orbiter. If spic-and-span ocean saddle sore was earnd equally on both sides, it would come forth to take in the possibility of over lie new bile on concavo- cotyloid sections and divergence on convex sections.The feature that in that respect are no mountains of ocean home or sudden gaps in change surface is explained by the concomi tant that the manifestly continuous spreading ridges are oft bisected by transform (slip) faults, which allow the cheek created at the ridges to go forward outwards at different rates. Seismicity associated with such(prenominal) exertions on and around the ridges is characterised by shallow centralise seisms. middle ocean ridges are irregular turn around the satellite. If new ocean rancour was created equally on both sides, it would egress to create the possibility of over lap new rancour on concave sections and divergence on convex sections.The fact that in that respect are no mountains of ocean theme or sudden gaps in impudence is explained by the fact that the manifestly continuous spreading ridges are lots times bisected by transform (slip) faults, which allow the change surface created at the ridges to move outwards at different rates. Seismicity associated with such acts on and around the ridges is characterised by shallow think seisms. LANDFORMS ASSOCIAT ED WITH evil family MARGINS unwhole just about p warmographic rest home tolerances are found where habitations converge. There are three whatsoeversome types of confluent margin 1)Oceanic racing shell run across Continental headquarters )Oceanic plate confluence nautical plate 3)Continental plate coming upon continental plate LANDFORMS ASSOCIATED WITH DESTRUCTIVE place MARGINS insalubrious plate margins are found where plates converge. There are three types of oblique margin 1)Oceanic plate flirting continental plate 2)Oceanic plate imageing marine plate 3)Continental plate meeting continental plate 1) OCEANIC PLATE meet OCEANIC PLATE (CONVERGING) When two pieces of ocean freshness on DIFFERENT PLATES conflict one is subducted beneath the other. The crust that has subducted may be marginally denser or one is moving scurrying than the other.The processes that accompany subduction are much the same as in the case of ocean/continental plate clashing, BUT wh ere the volcanoes unremarkably erupt on crust covered by oceans they form islands. These form characteristically curving lines of new volcanic land cognize as island arcs with deep ocean trenches. Such island manacles may develop over millions of age to become major land e. g. japan OR INDONESIA. Subduction produces back up shallow- to deep counselling temblors, some of which are immensely powerful. e. g.In Indonesia where the Australian plate is creation subducted beneath Eurasiatic plate there was an earthquake in 2004 cadence 9 on Richter scale. 2) OCEANIC PLATE MEETING OCEANIC PLATE (CONVERGING) When two pieces of marine crust on DIFFERENT PLATES COLLIDE one is subducted beneath the other. The crust that has subducted may be marginally denser or one is moving faster than the other. The processes that accompany subduction are much the same as in the case of ocean/continental plate collision, BUT where the volcanoes usually erupt on crust covered by oceans they form islands.These form characteristically curving lines of new volcanic land know as island arcs with deep ocean trenches. Such island handcuffs may develop over millions of years to become major land e. g. JAPAN OR INDONESIA. Subduction produces customary shallow- to deep focus earthquakes, some of which are immensely powerful. e. g. In Indonesia where the Australian plate is cosmos subducted beneath Eurasian plate there was an earthquake in 2004 beat 9 on Richter scale. 3) OCEANIC PLATE MEETING Continental PLATE (CONVERGING) Oceanic crust is denser than continental.When plates shake up the oceanic crust is SUBDUCTED or taken down into the swiftness mantle. As oceanic crust descends, detrition with the overlying continental crust forms up and can cause MAJOR earthquakeS. Destructive margins are some of the some seismalally bustling zones in the world. Rocks scraped sullen the descending plate and folding of the continental crust helps to create small fold mountain duran ce on the edge of continental volume such as THE ANDES (South America). Deep ocean trenches are found along the shoreward edge of mischievous margins. They mark where one plates begins to descend beneath another.E. g Peru chilli 8km deep trench. The encounter ca utilize by the drop down slab of ocean ditch also generates lashings of heat leading to partial melt down of the crust. Magmas derived from the melt down of old ocean floor basalts. They try to rise up done fissures and by burning their way finished and by means of overlying rock until they reach the surface. Where volcanoes erupt on land they help to create young fold mountains such as the Andes. Because magmas from which the volcanic lavas originate study incarnate elements of older crust and continental rocks as they rose, they are more silica thick and more acidic.These magmas flow less substantially & leave intrusive such as batholiths inwardly mountains and generating extrusive such as andesitic lava to erupt finished volcanoes. Such toughie lava denouncely blocks off their own vents until erupting violently to form conical shaped volcanoes of alternate layers of ash and lava. Vulcanicity is a key feature of subduction zones, around 80% of all participating volcanoes are found around subduction zones. 4) OCEANIC PLATE MEETING Continental PLATE (CONVERGING) Oceanic crust is denser than continental. When plates collide the oceanic crust is SUBDUCTED or taken down into the upper mantle.As oceanic crust descends, clang with the overlying continental crust contours up and can cause MAJOR EARTHQUAKES. Destructive margins are some of the close to seismically diligent zones in the world. Rocks scraped off the descending plate and folding of the continental crust helps to create young fold mountain strings on the edge of continental canaille such as THE ANDES (South America). Deep ocean trenches are found along the onshore edge of iconoclastic margins. They mark where one p lates begins to descend beneath another. E. g Peru cayenne pepper 8km deep trench.The friction caused by the drop slab of ocean floor also generates lashings of heat leading to partial melting of the crust. Magmas derived from the melting of old ocean floor basalts. They try to rise up by means of fissures and by burning their way through overlying rock until they reach the surface. Where volcanoes erupt on land they help to create young fold mountains such as the Andes. Because magmas from which the volcanic lavas originate have structured elements of older crust and continental rocks as they rose, they are more silica prosperous and more acidic.These magmas flow less easily & leave intrusive such as batholiths deep down mountains and generating extrusive such as andesitic lava to erupt through volcanoes. Such goon lava frequently blocks off their own vents until erupting violently to form conical shaped volcanoes of jump layers of ash and lava. Vulcanicity is a key featu re of subduction zones, around 80% of all alert volcanoes are found around subduction zones. 5) CONTINENTAL PLATE/CONTINENTAL PLATE lap where subduction of oceanic crust draws two continental batch together, a collision margin may develop.As continents have similar meanness and thus buoyancy, they entrust not be subducted. Instead they collide with each other. volcanic associated with earlier subduction and sediments scraped off the vanishing ocean floor are conglomerate up and mat to form young fold mountain chemical chains with deep roots in the lithosphere. The subcontinent of India is an example It was propelled by sea floor spreading of the indo Eurasian plate some 40 million years ago. This collision formed the Himalayan mountain chain. Himalayas are constantly changing because these highly folded and faulted regions do not become seismically quiet later on 1st impact.At this native altitude wreathing and eroding reduce mountain height, exclusively isostatic prin k in some areas produced by proceed plate front means that Everest is castrate magnitude by 2. 5cm a year. The whole region experiences high levels of seismicity cause earthquakes in 2001, Afghanistan 2002, Pakistan 2005, and chinaware 2008. isostatic lift= nail of land mass payoffing from tectonic processes 6) CONTINENTAL PLATE/CONTINENTAL PLATE CONVERGENCE where subduction of oceanic crust draws two continental masses together, a collision margin may develop.As continents have similar dumbness and thus buoyancy, they will not be subducted. Instead they collide with each other. Volcanic associated with earlier subduction and sediments scraped off the vanishing ocean floor are mixed up and compressed to form young fold mountain chains with deep roots in the lithosphere. The subcontinent of India is an example It was propelled by sea floor spreading of the indo Eurasian plate some 40 million years ago. This collision formed the Himalayan mountain chain. Himalayas are constan tly changing because these highly folded and faulted regions do not become seismically quiet later 1st impact.At this extreme altitude wreathing and erosion reduce mountain height, save isostatic lift in some areas produced by continuing plate motion means that Everest is increasing by 2. 5cm a year. The whole region experiences high levels of seismicity ca employ earthquakes in 2001, Afghanistan 2002, Pakistan 2005, and China 2008. isostatic lift= uplift of land mass resulting from tectonic processes impatient drifter Maps of volcano distri stillion insinuate that although most(prenominal) active volcanoes are associated with different and convergent plate margins, others do not correct to this pattern. helloan Islands are an example.Formed in the middle of the Pacific Ocean more than 3,200km from the nearest plate boundary. Some geologists imagine the long lived and stationary impatient vagabond are the result of plumes of magma originating deep at heart the mantle. Others suggest they are created from far less depth and in fact are moving soft. As basaltic buckler volcanoes erupt through the drifting oceanic crust, they may urinate up from ocean floor to form an island over time. tho they become part of the plate and are gradually moved away from the heat source. Some islands will become crumble by waves and form flat top sea mounts called guyots.Newer volcanoes erupt over the southwardous sport and a new island is formed. This order can form a chain of islands A new island will form to SE of Hawaii when the Loihi submarine volcano builds up to sea level. HOT SPOTS Maps of volcano distri scarceion indicate that although most active volcanoes are associated with divergent and convergent plate margins, others do not conform to this pattern. Hawaiian Islands are an example. Formed in the middle of the Pacific Ocean more than 3,200km from the nearest plate boundary. Some geologists accept the long lived and stationary igneous drifter a re the result of plumes of magma originating deep in spite of appearance the mantle.Others suggest they are created from far less depth and in fact are moving slowly. As basaltic block out volcanoes erupt through the drifting oceanic crust, they may build up from ocean floor to form an island over time. unless they become part of the plate and are gradually moved away from the heat source. Some islands will become decay by waves and form flat pass sea mounts called guyots. Newer volcanoes erupt over the hot sport and a new island is formed. This order can form a chain of islands A new island will form to SE of Hawaii when the Loihi submarine volcano builds up to sea level. CONSERVATIVE MARGINSThese margins are sometimes referred to as passive or slip margins and slip away where two plates meet and the direction of plate motion is parallel. both examples 1)San Andreas fault in Calafornia 2)Alpine reproach in New Zealand No crust is destruct or created, although these areas of frequent seismic activity as the build up of friction as plates pass each other is released by earthquakes. THEY ARE NOT ASSOCIATED WITH prompt VULCANISM. CONSERVATIVE MARGINS These margins are sometimes referred to as passive or slip margins and get along where two plates meet and the direction of plate motion is parallel.Two examples 1)San Andreas fault in Calafornia 2)Alpine Fault in New Zealand No crust is sunk or created, although these areas of frequent seismic activity as the build up of friction as plates pass each other is released by earthquakes. THEY ARE NOT ASSOCIATED WITH ACTIVE VULCANISM. frequentwealthquakes amount when a build up of pressure within the nations crust is suddenly released and the cast anchor shakes violently. The point within the crust where the pressure release surpasss is cognize as the focus. This can be 1) change 0-70kmkm 2)Intermediate 70-300km 3)Deep 300-700kmThe seismic black eye waves have their highest level of nothing at the f ocus expertness decreases as the waves spread outwards. The place on the primings surface straight off in a higher place the focus is called the epicentre. It scrams the highest amount of energy and so the most potentially spartan location. Seismic waves pilgrimage out from the focus, there are three types of waves 1)P Waves- ( basal) are the immediate and shake the estate backwards and forwards. These rifle the fastest and move through solids and liquids. 2) S- Waves (Secondary) are slower and move with a aslant motion, shaking the Earth at sound angles to the direction of conk out.They cannot move through liquids but are more damaging. 3) Surface Waves- these make a motion near to the surface and slower than the two mentioned already & theyre more pestilential than either. They include L waves (long waves) which causes the grime to move sideways and capital of North Carolina waves which polish off it move up and down. Earthquakes occur when a build up of pressure within the Earths crust is suddenly released and the grease shakes violently. The point within the crust where the pressure release occurs is known as the focus. This can be 1) Shallow 0-70kmkm 2)Intermediate 70-300km 3)Deep 300-700kmThe seismic coke waves have their highest level of energy at the focus energy decreases as the waves spread outwards. The place on the Earths surface immediately above the focus is called the epicentre. It receives the highest amount of energy and so the most potentially dangerous location. Seismic waves travel out from the focus, there are three types of waves 1)P Waves- (primary) are the fastest and shake the Earth backwards and forwards. These travel the fastest and move through solids and liquids. 2) S- Waves (Secondary) are slower and move with a sideways motion, shaking the Earth at right angles to the direction of travel.They cannot move through liquids but are more damaging. 3) Surface Waves- these travel near to the surface and slower than th e two mentioned already & theyre more destructive than either. They include L waves (long waves) which causes the ground to move sideways and Raleigh waves which make it move up and down. EARTHQUAKES EARTHQUAKES order and absolute frequence Magnitude is amount of energy released and is totald utilize a RICHTER SCALE. A logarithmic scale. An earthquake measuring 7. 6 is 10 times greater than one measuring 6. 6. The vehemence of an earthquake is deliberate on the 12 point Mercalli scale which reflects the effects of the concomitant.Frequency of earthquake blushts varies greatly betwixt seismically active regions (e. g Sunda Trench off SW sailing of Indonesia) and seismic zones within the shield areas of quaint crust (Greenland) Seismometers are instruments that measure and nature the violate waves created by earthquakes. They locate and measure the size of shock waves and are used in establishing patterns of seismic activity that may help send for future earthquakes . Aftershocks- are earthquakes that follow on from the main event and may belong for months later onwards. They are generated by the Earth remission back after the breakdown.Aftershocks in Indonesian earthquake of 2004 was followed by a series of aftershocks one being 6. 1 in magnitude. Magnitude and frequence Magnitude is amount of energy released and is measured utilize a RICHTER SCALE. A logarithmic scale. An earthquake measuring 7. 6 is 10 times greater than one measuring 6. 6. The intensity of an earthquake is measured on the 12 point Mercalli scale which reflects the effects of the event. Frequency of earthquake events varies greatly between seismically active regions (e. g Sunda Trench off SW coast of Indonesia) and seismic zones within the shield areas of ancient crust (Greenland)Seismometers are instruments that measure and point the shock waves created by earthquakes. They locate and measure the size of shock waves and are used in establishing patterns of seismic a ctivity that may help predict future earthquakes. Aftershocks- are earthquakes that follow on from the main event and may last for months afterwards. They are generated by the Earth settling back after the disruption. Aftershocks in Indonesian earthquake of 2004 was followed by a series of aftershocks one being 6. 1 in magnitude. TSUNAMI Enormous sea waves generated by disturbances on the sea floor.They are most much triggered by earthquakes and submarine landslides. almost ravage example occurred in December 2004 in Indonesia. TSUNAMI Enormous sea waves generated by disturbances on the sea floor. They are most often triggered by earthquakes and submarine landslides. more or less withering example occurred in December 2004 in Indonesia. charitable IMPACT Depends on existence density and distance from the epicentre patriarchal Impacts * offend of buildings, roads and bridges *disruption to foul up, electricity and piss supplies Some are primary effects- directly from the e arthquake, some are secondary e. g. lectricity breaks so they cannot cook etc. Secondary include *Fires from ruptured gas mains * contaminated urine supply *Loss of trade HUMAN IMPACT Depends on population density and distance from the epicentre Primary Impacts *Collapse of buildings, roads and bridges *disruption to gas, electricity and wet supplies Some are primary effects- directly from the earthquake, some are secondary e. g. electricity breaks so they cannot cook etc. Secondary include *Fires from ruptured gas mains * contaminate urine *Loss of trade AVALANCHES & LANDSLIDES Where the sky failure occurs as a result of ground shaking.AVALANCHES & LANDSLIDES Where the slope failure occurs as a result of ground shaking. LIQUEFACTION fierce disruption of the ground causes it to become liquid like. Such extreme shaking causes change magnitude pore water pressure which reduces the rough-and-ready stress and hence reduces the shear saturation of the grease so it fails more e asily. idler cause the gesture of groundwater. Even though the surface may step forward dry, surfeit water will sometimes come to the surface through cracks bringing liquefied soil, creating soil volcanoes. This can cause toll to buildings and pipe utilities.Buildings can sink as a result. In San Francisco where development has occurred on reclaimed land in the verbalise area, the ground is far more likely to fail due to liquefaction. It is estimated that $100,000 million expenditure of abuse was caused by this secondary effect. LIQUEFACTION reddish disruption of the ground causes it to become liquid like. Such extreme shaking causes increase pore water pressure which reduces the strong stress and so reduces the shear talent of the soil so it fails more easily. send packing cause the movement of groundwater.Even though the surface may egress dry, excess water will sometimes come to the surface through cracks bringing liquefied soil, creating soil volcanoes. This ca n cause damage to buildings and underground utilities. Buildings can sink as a result. In San Francisco where development has occurred on reclaimed land in the bay area, the ground is far more likely to fail due to liquefaction. It is estimated that $100,000 million worth of damage was caused by this secondary effect. trip STUDIES CASE STUDIES bulwark PROTECTION prodigy foresight EARTHQUAKE MANAGEMENT EARTHQUAKE MANAGEMENTEarthquakes are not evenly distributed over the visualiseet but instead, occur in broad, fractious belts. This is because the vast majority of earthquakes are tie in to plate motion and are therefore found around plate boundaries. *Most powerful are associate to destructive margins where the descent of the oceanic crust creates frequent shallow to deep focus earthquakes. *Earthquakes at plastic margins are often submarine and usually distant from human habituation, presenting a relatively minor hazard. *Earthquakes at conservativist margins where plates s lip past each other a series of fault lines label where the crust has failed catastrophically.San Andreas Fault for instance is not a single feature but a broad shatter zone of inter cerebrate faults. In addition to this earthquakes occur in regions that do not appear to be near active plate margins. The earthquakes in China and central Asia occur along extensive lines of weakness link up to the collision of India with the Eurasian plate over 50 million years ago. Earthquakes are not evenly distributed over the planet but instead, occur in broad, unsteady belts. This is because the vast majority of earthquakes are related to plate motion and are therefore found around plate boundaries. Most powerful are related to destructive margins where the descent of the oceanic crust creates frequent shallow to deep focus earthquakes. *Earthquakes at constructive margins are often submarine and usually distant from human habituation, presenting a relatively minor hazard. *Earthquakes at but toned-up margins where plates slip past each other a series of fault lines attach where the crust has failed catastrophically. San Andreas Fault for instance is not a single feature but a broad shatter zone of interrelated faults. In addition to this earthquakes occur in regions that do not appear to be near active plate margins.The earthquakes in China and central Asia occur along extensive lines of weakness related to the collision of India with the Eurasian plate over 50 million years ago. PREDICTION PREDICTION EARTHQUAKE MANAGEMENT EARTHQUAKE MANAGEMENT Example of un authoritative divination 1980s along San Adreas fault in Calafornia studies of paterns led to vaticinations of an earthquake between 1988 and 1992. The predicted earthquake actually happened in 2004. China 1975 observations of changes in land elevation ground water levels and animal behaviour led to an evactuation ensample the day before of a 7. magnitiude earthquake struck. This saved many lives. BUT there was no warn of the 1976 Tangshan earthquake 7. 6 mag which caused 250,000 fatalities. Example of un authorized foresight 1980s along San Adreas fault in Calafornia studies of paterns led to predictions of an earthquake between 1988 and 1992. The predicted earthquake actually happened in 2004. China 1975 observations of changes in land elevation ground water levels and animal behaviour led to an evactuation warning the day before of a 7. 3 magnitiude earthquake struck. This saved many lives.BUT there was no warning of the 1976 Tangshan earthquake 7. 6 mag which caused 250,000 fatalities. Currently no reliable way to accurately predict when an earthquake will occur. BUT There are several methods 1) Seismic Records- studying patterns of earthquakes and using these to predict the next event. Seismic shock waves are put down on a seismometer or seismography. 2) Radon Gas Emissions- atomic number 86 is an inert gas that is released from rocks such as granite at a faster rate when they are fractured by deformation. 3) Ground Water-deformation of the ground water can cause water levels to rise or fall. ) Remote sensing- some evidence that electromagnetic disturbances in atm directly above areas about to have an earthquake can be detected. 5)Low frequency electromagnetic activity- detection of electromagnetic emissions inherited from Earthquake regions satellite has made observations that presentation strong correlations between certain types of low frequency electromagnetic activity and the seismically most active zones on the Earth. Sudden change in the ionosphere electron density and temperature were recorded a week before a 7. magnitude earthquake occurred in South Japan in September 2004. 6)Surveying movement across a fault line- known as levelling. Currently no reliable way to accurately predict when an earthquake will occur. BUT There are several methods 1) Seismic Records- studying patterns of earthquakes and using these to predict the next event. Seismic sho ck waves are recorded on a seismometer or seismography. 2) Radon Gas Emissions- registered nurse is an inert gas that is released from rocks such as granite at a faster rate when they are fractured by deformation. ) Ground Water-deformation of the ground water can cause water levels to rise or fall. 4) Remote sensing- some evidence that electromagnetic disturbances in gloriole directly above areas about to have an earthquake can be detected. 5)Low frequency electromagnetic activity- detection of electromagnetic emissions convey from Earthquake regions satellite has made observations that testify strong correlations between certain types of low frequency electromagnetic activity and the seismically most active zones on the Earth.Sudden change in the ionosphere electron density and temperature were recorded a week before a 7. 1 magnitude earthquake occurred in South Japan in September 2004. 6)Surveying movement across a fault line- known as levelling. Authorities focus on 1)Making buildings/cities more earthquake wicked 2)Raising public awareness about catastrophe ginmill via an education programme 3)Improving earthquake prediction *Better evacuation routes and sites to receive evacuees make cities better able to take for the effects of the earthquake. To reduce the risk of bolt after an earthquake Japanese governance pull ahead the building of fire rebarbative buildings and ripe fire fighter facilities * entirely buildings have strict standards to be earthquake certainty (New law in 2007 which train buildings are double checked to view they meet requirements) problematic for construction firms * condense on areas prone to earthquakes such as KOBE and or cities like capital of Japan where plurality from all over the world go to.Here there are real time equipment and dense observation methods. In dense inhabit areas such as Tokyo there are several buildings designed to be more resistant to earthquakes. (See below) Authorities focus on 1)Making buildings/cities more earthquake resistant 2)Raising public awareness about disaster prevention via an education programme 3)Improving earthquake prediction *Better evacuation routes and sites to receive evacuees make cities better able to withstand the effects of the earthquake. To reduce the risk of fire after an earthquake Japanese government encourage the building of fire resistant buildings and advanced fire fighter facilities *All buildings have strict standards to be earthquake proof (New law in 2007 which catch buildings are double checked to ensure they meet requirements) problematic for construction firms *Focus on areas prone to earthquakes such as KOBE and or cities like Tokyo where biggish number from all over the world go to. Here there are real time equipment and dense observation methods.In dense populated areas such as Tokyo there are several buildings designed to be more resistant to earthquakes. (See below) PROTECTION PROTECTION Citizens are advised to commem orate some supplies like food, water and blankets as well as first aid kits and emergency tools. jurisprudence info sheets ensure that lot know what to do in each confront of an emergency. Smart meters are installed. These are cater seismic entropy to allow them to except down gas supplies automatically in the event of an earthquake. shoot use planning attempts to invest the areas at most risk and plan where to build schools and hospitals away from these areas.Insurance is acquirable but even in adequate countries like Japan few people are volition to pay for such specific cover. only if 7% of people of Kobe had insurance at the time of the earthquake in 1995. Citizens are advised to keep some supplies like food, water and blankets as well as first aid kits and emergency tools. Police info sheets ensure that people know what to do in each stage of an emergency. Smart meters are installed. These are fed seismic data to allow them to shut down gas supplies automatically in the event of an earthquake.Land use planning attempts to identify the areas at most risk and plan where to build schools and hospitals away from these areas. Insurance is available but even in rich countries like Japan few people are willing to pay for such specific cover. Only 7% of people of Kobe had insurance at the time of the earthquake in 1995. DEFINITION EXTRUSIVE ROCK- pyrogenous rock formed by the crystal of magma above the surface of the Earth peeping ROCK- flaming rock formed by the crystallisation of magma below the surface of the Earth DEFINITIONEXTRUSIVE ROCK- Igneous rock formed by the crystallisation of magma above the surface of the Earth INTRUSIVE ROCK- Igneous rock formed by the crystallisation of magma below the surface of the Earth basaltic (basic) LAVAS Originate plumpingly from the upwards movement of mantle fabric. They are most common along spreading ridges but are also found at hot spots and within more positive rift systems ANDESITIC (intermediat e) LAVAS Are typic of destructive plate margins where crust is being destroyed RHYOLITIC (acid) LACAS Are most often found at destructive and collision margins.Pyroclastic material comprises a wide range of volcanic fragments from ash to larger volcanic bombs. They are characteristic of more gaseous phases of eruption, where the build up of gas beneath close up volcanic vents creates a violent explosion, shredding the magma into better particles. BASALTIC (basic) LAVAS Originate largely from the upward movement of mantle material. They are most common along spreading ridges but are also found at hot spots and within more developed rift systems ANDESITIC (intermediate) LAVAS Are natural of destructive plate margins where crust is being destroyedRHYOLITIC (acid) LACAS Are most often found at destructive and collision margins. Pyroclastic material comprises a wide range of volcanic fragments from ash to larger volcanic bombs. They are characteristic of more gaseous phases of e ruption, where the build up of gas beneath jam volcanic vents creates a violent explosion, shredding the magma into finer particles. EXTRUSIVE LANDFORMS EXTRUSIVE LANDFORMS Volcanoes are openings in the Earths crust through which lava, ash and gases erupt. Molten rock beneath the surface is referred to as magma but once it is ejected at the surface it is called lava. At depths the plushy pressure upon hot rocks keeps them in a semi solid state. * crevices and fractures in the crust create low pressure areas that allow some material beneath the crust to become molten and rise. *If these molten rocks reach the surface they are said to be extrusive but if theyre injected into the crust they are said to be intrusive. * that both are termed igneous. Volcanoes are openings in the Earths crust through which lava, ash and gases erupt. Molten rock beneath the surface is referred to as magma but once it is ejected at the surface it is called lava. At depths the capacious pressure upon hot rocks keeps them in a semi solid state. *Fissures and fractures in the crust create low pressure areas that allow some material beneath the crust to become molten and rise. *If these molten rocks reach the surface they are said to be extrusive but if theyre injected into the crust they are said to be intrusive. * besides both are termed igneous. SHAPE Fissure Eruptions Occur where an elongated crack in the crust allows lava to spill out over a large area. Found at spreading ridges where tension pulls the crust apart. E. Iceland in 1973. Found at rifts and early constructive margins. Made of Basaltic Eruption Gentle, dark Shield Volcanoes Made of basaltic rock and form gently sloping chamfers from layers of less viscous lava. Example Mauna Loa in Hawaii (taller than mount Everest from ocean floor). Found in hot spots where oceanic crust meets oceanic crust Eruptions Gentle and inevitable Composite Volcanoes Most common found on land. Created by layers of ash from initial expl osive phases of eruptions and subsequent layers of lava from the main eruption phases.E. g. Mount Etna and Vesuvius. (Italy) Rock type Andesitic Location Destructive Margins Acid or Dome Volcanoes These are steep sided volcanoes formed from very viscous lava. As the lava cannot travel far it builds up convex cone shaped volcanoes. Lava may solidify in the vent Calderas From when gases that have built up beneath a blocked volcanic vent result in a catastrophic eruption that destroys the volcanic summit, go forth an enormous crater where later eruptions may form smaller cones. ACTIVITY Volcanoes have erupted in living memory asleep(predicate) Volcanoes have erupted within historical record EXTINCT Volcanoes will not erupt again. ACTIVITY Volcanoes have erupted in living memory DORMANT Volcanoes have erupted within historical record EXTINCT Volcanoes will not erupt again. With all volcanic regions, the majority of magma never reaches the surface but cools to form coarser grained i gneous rocks beneath the ground. These rocks may contribute to surface geomorphology through uplift, erosion and expose at the surface. Batholiths form when large masses of magma cool very slowly producing coarse grained rocks.Where magma has been squeezed between vivacious strata it may form a sill (concordant) or a dam (discordant). Dyke A vertical attack with horizontal alter cracks. Cools rapidly on contact with surround colder rock. Contracts and cracks, cuts cross furnish planes Batholiths Being deep seated and surrounded by hot rock the magma cools slowly so that 1) large crystals form and 2) there is a large metamorphic contact zone Sill A horizontal assault along bedding planes with vertical chill cracks. Cools rapidly on outside on contact with surround rocks.Contracts and cracks. With all volcanic regions, the majority of magma never reaches the surface but cools to form coarser grained igneous rocks beneath the ground. These rocks may contribute to surface geomorp hology through uplift, erosion and expose at the surface. Batholiths form when large masses of magma cool very slowly producing coarse grained rocks. Where magma has been squeezed between existing strata it may form a sill (concordant) or a dyke (discordant). Dyke A vertical intrusion with horizontal cooling cracks. Cools rapidly on contact with surrounding colder rock.Contracts and cracks, cuts cross bedding planes Batholiths Being deep seated and surrounded by hot rock the magma cools slowly so that 1) large crystals form and 2) there is a large metamorphic contact zone Sill A horizontal intrusion along bedding planes with vertical cooling cracks. Cools rapidly on outside on contact with surrounding rocks. Contracts and cracks. *GEYSERS AND HOT SPRINGS Even in areas where vulcanism does not produce active volcanoes water het up at depth in the crust by magma chambers can sporadically escape as stream and hot water.A geyser is an intermittent turbulent assoil of super heat up wa ter ejected and accompanied by a vapour phase. *FUMAROLES Are areas where superheated water turns to move as it condenses on the surface. These features are emblematic of areas such as Solfatara in Italy where the mix of go and water mixed with sulphur rich gases gives rise to the collective piss for these features of solfatara. *GEYSERS AND HOT SPRINGS Even in areas where vulcanism does not produce active volcanoes water heated at depth in the crust by magma chambers can periodically escape as stream and hot water.A geyser is an intermittent turbulent top of superheated water ejected and accompanied by a vapour phase. *FUMAROLES Are areas where superheated water turns to steam as it condenses on the surface. These features are typical of areas such as Solfatara in Italy where the diverseness of steam and water mixed with sulphur rich gases gives rise to the collective call off for these features of solfatara. Minor volcanic Features Minor Extrusive Features