GEOGRAPHY ALL UNITS
Montserrat case study: General facts (6)
-Located in the Caribbean -Part of chain of islands formed where the Atlantic and Caribbean plate have collided -Soufriere Hills (where volcano is) -Plymouth is capital city -Big eruption in Aug 1997 -Overseas British territory
Earthquake case study: General facts (5)
-March 11th, 2011 -2:46pm -centered on seafloor 45 miles east of Tokyo at 15 miles below surface -shaking lasted about 6 mins -shifted earth's axis 6cm
Predict earthquakes
-Monitor using GPS -Heat sensors -Lasers -Map previous tectonic events -Temperature -Seismicity
Destructive boundary explained
-Ocean and continental plate converge -Denser oceanic crust is forced down into the mantle (subduction) -Oceanic crust is melted and destroyed -Explosive volcanos are formed -Powerful earthquakes occur as the plate moves
Constructive boundary explained
-Oceanic plates diverge -Mantle rock melts and erupts lava -New crust is formed and sea floor grows larger -Undersea volcanos form mid-ocean ridges -Minor earthquakes occur as the plates move
Earthquake case study: Effects (11)
-Over 15,000 confirmed dead -15,000 missing -less than an hour after earthquake, tsunami occurred 128ft high across 6 miles -Nuclear power plant leak -more than 200,000 people evacuated -over 164,000 households no electricity -at least 170,000 households without water -at least 46,000 buildings destroyed -over 16 trillion yen in dammage ($232 billion) -71 damaged bridges -3970 road damages
Montserrat case study: Short term responses (7)
-People evacuated from south to north of island -Medical assistance -Food and water given -Shelter provided -Search party for those buried in ash -Constant weather monitoring -Abandonment of capital city
Montserrat case study: Social effects (6)
-People evacuated to north of island -Killed 19 farmers -Many towns and villages buried -Over 60% of the south and central area of island became uninhabitable -Population now half of what is was -Hotels destroyed
Effects of Volcanic eruptions
-Primary (immediate) e.g. homes destroyed, death -Secondary (longer term) e.g. loss of business, transport problems Effects can be positive or negative
Montserrat case study: Environmental facts (4)
-Pyroclastic flows broke and flattened thousands of trees -Forests and beaches destroyed -Half of island inhabitable -Plymouth covered in layers of ash
Montserrat case study: Causes (2)
-Sits on a destructive plate boundary between the small Caribbean plate and the Atlantic plate. --> these two plates are moving towards each other resulting in seismic activity as the denser oceanic crust is forced downwards
Protect from earthquakes
-Specific earthquake proof buildings -Strength foundations -Check buildings
Earthquake case study: Causes (2)
-Struck offshore Japan along subduction zone where two tectonic plate collided -East of Japan the Pacific plate dove beneath the overriding Eurasian plate
Conservative boundary explained
-Tectonic plates move in different directions or at different speeds -Plates become locked together -Pressure builds until rock snaps along fault -Plates move suddenly causing powerful earthquakes
Montserrat case study: Economic effects (3)
-Transport links were cut off -Tourism decrease -Shops and businesses destroyed
Factors influencing the impacts of an earthquake (5)
-Urban vs. Rural ares -Day or Night -Preparational warning -Water or land -HIC or LIC
Collision plate margin -example and earthquakes/volcanos?
*Go up E.g. Indo-Austrailian/ Eurasian plate -Strong earthquakes
Constructive plate margin - example and earthquake/volcanos?
*Goes away from each other E.g. Eurasian Plate/North American -Volcanos and weak earthquakes
Destructive plate margin -example and earthquakes/volcanos?
*One goes under/they go towards each other E.g. South American/ Pacific plate -Violent volcanos and strong earthquakes
Conservative plate margin -example and earthquakes/volcanos?
*Side by side E.g. North American/ Pacific plate -Strong earthquakes
Montserrat case study: Long term responses (5)
-An exclusion zone set up in volcanic region -Volcanic observatory built -New roads and airport built -Services in North were expanded -Presence of volcano increased tourism
Continental Crust
-Between 25-100km thick -Less dense/lighter -Does not sink -Does not get destroyed -Made mostly of granite -Older than oceanic crust
Oceanic Crust
-Between 5-10km thick -Denser/heavier -Continually being renewed and destroyed -Made mostly of basalt -Younger
Collision boundary explained
-Continental plates converge -Plates are not dense enough to sink into the mantle -Plates buckle and form fold mountains -There are powerful earthquakes but no volcanic eruptions
Prepare for earthquakes
-Educate people on how to prepare and react -Have an evacuation plan -Train emergency services
Earthquake case study: Responses
-Within hours of earthquake, social networking sites helping people donate to disaster relief funds -Clean up operations ongoing many months after -$1.1 million clothes from gap -3 mins after earthquake, tsunami warning -59 search and rescue experts, four medics and two sniper dogs flew out -116 countries and 28 international organisations offered assistance -Jackie Chan donated $3million
Factors to consider with prediction and planning
-time of day -HIC or LIC -Building materials -Season -Rock/ soil type -Depth of focus -frequency of hazards -Rural or urban -Proximity to epicenter
Types of volcanoes
1. Composite 2. Cinder 3. Shield
What is involved in the Hydrological Cycle?
1. Condensation 2. Precipitation 3. Groundwater 4. Interception 5. Through flow 6. Infiltration 7. Surface run off 8. Evapotranspiration 9. Overland flow 10. Surface Storage
Composite volcano
A cone shaped volcano formed from layers of ash and lava
Definition of River
A large natural stream of water flowing in a channel to the sea, a lake, or another such stream.
Tectonic plate
A large section/ slab of the Earth's crust
Richter scale
A logarithmic scale used to measure the magnitude of an earthquake
Hot spot
A place on the crust that is particularly thin and magma can escape
Continental plate
A plate that carries land
Oceanic Plate
A plate that carries ocean
Active volcano
A volcano that has erupted recently and is likely to again
Dormant volcano
A volcano that has not erupted recently but has a recorded eruption in the last 80 years. Dormant means sleeping
Extinct volcano
A volcano that is unlikely to erupt ever again. Extinct means dead
Mercalli Scale
A way of measuring/ grading the effects/ damage caused by an earthquake
Shield volcano
A wide, flat volcano created from runny lava that spreads over a long distance
What is a Drainage Basin?
An area from which rain water drains into the river
Mercalli Scale
Assesses damage. Scale is in Roman numerals
Where are volcanos found?
At constructive plate margin and destructive plate margins
Volcanos found on the mid-ocean ridge are on what type of plate margin?
Constructive
Why do plates move at different speeds and directions?
Convection currents that operate underneath the earth
Earth's three main layers
Core, Mantle, Crust
Fault
Crack in Earth's crust
Volcanos found where an ocean plate is pushed under a continental plate are on what the of plate margin?
Destructive
Main two plate boundaries for earthquakes to form
Destructive boundary (causes MOST powerful earthquakes) and Conservative boundary (causes strong earthquakes
How do convection currents flow?
In different directions according to where the plate is
Core
Inside layer of the Earth
Earthquake case study
Japan March 11, 2011
Plate
Large section/ slab of the Earth's crust
What is Evapotranspiration?
Loss of water through vegetation and wild life
Why do people live near volcanoes?
MINERALS- the magma rinsing from deep inside the earth contains a range of minerals such as tin, silver, gold, copper and diamond- this makes the area ideal for both large scale commercial mining and smaller scale local activities GEOTHERMAL ENERGY- the heat from underground steam is used to drive turbines and produce electricity or to heat water supplies FERTIL SOILS- Volcanic rocks and ash are rich in minerals and can be used for soils after being broken down. When they do break down they form some of the richest soils on earth TOURISM- Volcanoes attract millions of visitors every year- tourism creates jobs, restaurants, hotels and tourist centre
Richter Scale
Measures strength (magnitude). Each point is 10x stronger Thant the one before (logarithmic) -Seismograph (reading) and Seismometer (machine) used
Mantle
Middle section of the Earth
Magma
Molten rock UNDER the surface
Volcano case study
Montserrat, Plymouth
Types of crust
Oceanic and Continental
Volcanoes at a destructive plate margin process
Oceanic and continental plates move together -> Oceanic plate forced downwards -> Rock melts -> Magma rises -> Volcano
Volcanoes at a constructive plate margin process
Pressure from mantle -> Magma rises and plates move apart -> Volcano forms -> Mid-ocean ridge
What is Precipitation?
Rain, snow, hail, sleet
Measuring Earthquakes
Richter Scale and Mercalli Scale
Aftershock
Shaking of the crust after the main quake
Plate boundary (margin)
The line where 2 plates meet
Crust
The outer layer of the Earth
Epicentre
The point on the surface directly above the focus
What is the Source of a river?
The starting point of the river
Responses to an eruption
These can be Short Term e.g. evacuation, first aid, water, food or Long Term e.g. rebuilding homes
Sesmic waves
Vibrations travelling through and over earth
What is Surface storage?
Water stored in lakes, ponds, etc.
What is Surface Runoff?
Water that doesn't soak into the ground, just runs into the river
What is Overland flow?
Water that flows over land
What is Condensation?
Water turning from vapour into raindrops
What is Interception?
Water which is stopped by vegetation
What is Through flow?
Water which moves through soil
Lava`
When ,magma breaks onto the surface of the Earth e.g. from volcano or hot spot
What is Groundwater?
When water flows through rocks
What is Infiltration?
When water soaks into the ground
Conservative (transform) margin definition
Where 2 plates are moving along side each other
Constructive (divergent) margin definition
Where 2 plates are moving apart and new land is created
Focus
Where an earthquake starts (below ground)
Destructive (convergent) boundary
Where an oceanic plate sinks beneath a continental plate and the crust is destroyed
