This document summarizes key concepts in physical geography related to plate tectonics, earthquakes, volcanoes, and case studies of volcanic eruptions and earthquakes. It describes how convection currents in the mantle cause plate movements at destructive, conservative, and constructive plate boundaries. Case studies on the 1995 Montserrat volcano eruption and the 2011 Japanese earthquake and tsunami detail their impacts and responses. A third case study summarizes the 2008 Sichuan earthquake in China that killed over 70,000 people.

1. Geography Revision: Physical Geography (Simpler, Shorterand Easier than the Revision
Guide)
Restless Earth
 Layersof the Earth - Crust, Mantle,Core
 How Do ConvectionCurrentsCause PlateMovement - Core heatsmoltenrockinthe mantle
(CreatesConvectionCurrent) Heatedrockrisesto the surface. At surface, convectioncurrents
moves tectonicplatesintocrust. Moltenrock cools, flowsback to be reheated.
 Continental Crustis thickerbutlessdense thanOceanicCrust.
Plate Boundaries, Volcanoes, Earthquakes
 Destructive Plate Boundaries - WhenContinental Crust(NazcaPlate) subductsunderneaththe
Oceanic Crust(SouthAmericanPlate) EarthquakesandEruptions frequenthere.
 Conservative Plate Boundaries - Twoplatesslidepasteachother(SanAndreasFault,California)
Earthquakes.
 Constructive Plate Boundaries - ConvectionCurrentspull crustapartforminga volcanicridge.
(EurasianPlate andNorthAmericanPlate)
 Tsunamis are formedwhenthere isaneruptionorearthquake underthe sea.This meansthe sea
bedriseswiththe plates - whichcreatesan opentopsphere of waterto move apart fromthe
epicentre inthe opposite direction,ashuge waves.
 ShieldVolcanoes - Constructive Plate Boundary.Thin,runnylava.Wide base,slopingsides.Low
Silicacontent.Erupt frequently...not violently.
 Cone Volcanoes - Destructive Plate Boundary.Stickylavaandash.Steepsides. Highsilicacontent
and gas amounts.Erupt infrequently...butviolently,includingpyroclasticflows.
 MeasuringMagnitude of Earthquakes:Richter Scale - Energy Released.Mercalli Scale - effects
or impacts, measuredinRomanNumeralsfrom1-12.
Predicting Earthquakes and Eruptions
 We do not know...
 Whenit will happen,where itwillhappen,how bigitwill be,whatotherimpactsitmayhave,
howmany people live there.
 We can see ...
 Animalsandbirdsmovingawayfromthe area,increase ingas emissions,increaseinsmaller
Earthquakes,watergettingwarmer,volcanoswelling.
Responses to an earthquake or eruption ...

2.  Trainedvolunteerstohelpinjuredandcleardebris.
 Cleanwaterto preventspreadof disease.
 Gatheringfood,shopscanbe damaged.
 Radiocommunication,phone linescouldbe damaged.
 Medical helptocare for the injured.
 A planto evacuate.
Strengthening Buildings
 Installingabandof concrete to the roof to stopwallsfallingoutwards.
 Verystrongframework.
 Strengthenwalls.
 Foundationsmade from steel andrubber- so the buildingswaysslightlywiththe quake.
 Diggingdeeperfoundations - more stability.
 Reinforce gas andwater pipessotheydon'tbreak.
Case Study: Montserrat Volcano, 1995
 The volcano had been dormant since the 17th
century.
 The eruption sentoutlava andash includingpyroclasticflows.
 Over6500 people outof 10000 leftthe island.
 The whole islandwasaffected.
 The eruptionhad economicand social effects.
Primary and Secondary Impacts
 Primary,Destructionof capital cityPlymouth.Itwascoveredashwhichdestroyed crops;also
the populationfromthe southernpart of the islandhadto be evacuatedtoa saferarea.
Forestswere ignitedbygaseswhichmeantamasslossof vegetationonthe island
 Secondary,half the original populationdidn’treturntothe island.Plymouthisnow aghost
town,originallyathrivingbusinesslocation;companieshave takenthemselvesto
neighbouringislandsormovedelsewhere onthe island.
Case Study: 2011 Japanese Earthquake and Tsunami
 9.0 on the RichterScale,struckJapansNorth East coast,Hit 11th
of March at 3PM.
 Destructive Plate Boundary,Earthquakehappenedatashallow depth(Only20Milesunder
the Pacific) ThiscombinedwithMagnitude causedTsunami.
 30ft wavesbatteredFukashimanuclearreactors. Despite beingturnedoff the reactors
exploded.

3.  Killedabout16000 people and damage costsstoodat $300 billion.4.4millionhouse-holds
withoutelectricity.300,000 refugees.
 Tsunami reachedHawaii andAlaskabutby thenitwas only2 metreshigh.Earthquake tilted
Earth’s axis.Coastlinedropped2metres.
Responses
 There were volunteersfromthe RedCrosswhohelpedout.
 US sentout soldierstoJapanto help.
 Othercountriesdonatedmoney.
 Compensationgivenout.
 Farms Cleared.
 SheltersMade.
 People Fledbefore Tsunami.
 There were emergencytexts.
 Supplykitswere available.
 Earthquake drillswere followed.
Case Study: 2008 Sichuan Earthquake
 7.8 Magnitude,900 childrendiedinschool,Buildingsfell down,Damswere damaged,10
millionpeopleaffectedand70000 dead.
 80% of buildingscollapsed,Roadsblocked,phone linesdown andayearon thingshave got
no better.
Responses
 Armywere deployedtosearchforpeople.
 Evacuations
 Took 3 days forarmy to get there.
 Aidfromothercountries.
 90 helicopterslookingfromabove.
 Communitystucktogether.
 Cost of repair– 75 billion.
 1 milliontemporaryhomesbuilt.
 People usedhandsandshovelstodigpeopleout.