geography ppe Flashcards
define immediate response
an impact that takes place immediately after the events of a natural hazard, always to save lives or reduce further death
define secondary effect
indirect impact of a natural event on a larger timescale
define natural hazard
a natural event that threatens people and environment
define climate change
long-term change in earth’s climate
define a biome
large-scale global ecosystem
define deforestation
process of cutting down large areas of trees
define intermediate technology
technology that is suited to the needs, skills and wealth of local people and environment
define desertification
the process of land becoming less fertile and less able for crops to grow
define abrasion
the process of rocks or boulders wearing away at a river bed or cliff face like sandpaper
define longshore drift
the process of sediment being transported along the coastline
what is a constructive plate margin
where plates move apart from one another
what is formed at a constructive plate margin
- shield volcano
- movement of plates can cause earthquakes
what is a destructive plate margin
usually involves an oceanic and continental plate moving towards each other
how is a composite cone volcano formed at a destructive plate margin
- plate sinks into mantle to form magma
- pressure of magma builds up beneath Earth’s surface
- magma escapes through weaknesses in rock and forms a composite cone volcano
what is formed at a destructive plate margin
- earthquakes
- composite cone volcano
what happens when two continental plates move towards each other
neither can sink so the land buckles upwards to fold mountains called collision margins, earthquakes can form here
what is a conservative plate margin
plates move past each other or side by side at different speeds
how is an earthquake formed at a conservative plate margin
- as plates move friction occurs and they become stuck
- pressure builds up because plates still trying to move
- pressure is released and sends huge amounts of energy causing earthquake
why can earthquakes at a conservative plate boundary be very destructive
they occur close to the Earth’s surface
what is an earthquake
the sudden violent shaking of the ground
what is the point where the earthquake originates known as
the focus
where are seismic waves most powerful
the epicentre
difference between epicentre and focus
focus in the crust whereas epicentre is on surface
what is the machine called that measures earthquakes
seismometer
what do modern scientists use instead of Richter scales to measure earthquakes
Moment magnitude scale
how do scientists use prediction to detect earthquakes
involves using seismometers to measure earth tremors
what are some issues with prediction and earthquakes
experts known where they’re going to happen just not when
what are some examples of protection against earthquakes
- rubber shock absorbers in foundation to absorb Earth tremors
- steel frames that can sway
- open areas outside buildings where people can assemble
how is preparation used against earthquakes
- drills are used in all public buildings so that people know what to do in the event of an earthquake
- reduces impact and increases chance of survival
where do volcanoes form
when magma reaches surface and erupts to form lava
features of a volcano
- magma chamber - where molten rock is stored underground
- main vent - channel through which magma travels to reach Earth’s surface
- secondary vent - some magma may escape through the side of volcano, especially if main vent is blocked
- crater - found at top of volcano where magma erupts from
positive effects of volcanoes
- geothermal energy is where heat from within the Earth is used to generate electricity
- ash ejected used as good fertiliser
- volcanoes attract tourists because of dramatic scenery
negative effects of volcanoes
- dangerous can kill people and damage property
- economic activity can suffer as businesses can’t operate after eruption
- habitats and landscape destroyed by lava
features of composite cone volcano
- viscous (sticky) lava
- steep sides as lava doesn’t travel far
- alternate layers of ash and lava
- violent eruptions
- longer periods between eruptions
features of shield volcano
- basic non-viscous lava
- gentle sides as lava travels far
- no layers
- less violent eruptions
- shorter periods between eruptions
how do scientists measure volcanoes
- seismometers used to measure earthquakes
- tiltmeters monitor changes in landscape as volcanoes can swell
- monitoring gases escaping using robots called Spiders
- measuring temperature change
- identifying patterns of activity
why do people live near volcanoes
- volcanic rock and ash provide fertile land
- tourists are attracted to volcano
- geothermal energy can be harnessed
- miners are contained in lava e.g. diamonds
what are the types of atmospheric cell
polar
ferrel
hadley
what is a tropical storm
very powerful low-pressure weather system which results in strong winds and heavy rainfall
features of a tropical storm
- central calm eye
- large cumulonimbus clouds caused by warm moist air condensing
how do tropical storms develop
- between 5 and 30 degrees latitude move westward because of easterly winds
- air above warm ocean is heated, when it hits 27 degrees the warm air rises quiclky causing low pressure
- as air continues to rise it draws more moist warm air leading to strong winds
- rising warm air spirals upwards, cools, condenses and large cumulonimbus clouds form
- clouds form eye wall and produce heavy rainfall
- centre of storm, cold air sinks where conditions are calm
how does climate change make tropical storms more intense
- warmer ocean surface temps and higher sea levels
- increasing wind speeds
- rainfall rates during storms could increase 20%
how can people predict tropical storms
with computer modelling that uses satellite images, weather instruments and computer-based prediction
what were some primary effects after Nepal earthquake
- centuries-old buildings destroyed like Changu Narayan Temple
- over 8,000 dead and 19,000 injured
- half of schools destroyed
what were some secondary effects after Nepal earthquake
- avalanche triggered at Mount Everest killing 20 people
- loss of tourism, major income for Nepal
- harvest reduced or lost so people starved
what were some immediate responses after Nepal earthquake
- UK sent over 100 search and rescue responders and medical experts
- aid workers from Red Cross helped
- crisis mapping was used to coordinate the response
what were some long-term responses after Nepal earthquake
- government task force created to help deal with future earthquakes
- people educated to do earthquake drills
- UK donated £73 million to Nepal for humanitarian response
how do human causes cause climate change
- agriculture lead to release of Nitrogen Oxides into atmosphere and Methane
- burning fossil fuels like coal, gas and oil release CO2 into the atmosphere
how do natural causes cause climate change
- orbital changes because earth has natural warming and cooling periods caused by Milankovitch cycles
- volcanic activity, CO2 released into atmosphere
- solar output as there can be fluctuations in amount of radiation from sun
characteristics of hot desert climate
- the climate is very hot, temps can exceed 40 degrees C, night can drop below freezing
- very dry <250mm of rain a year
- 2 seasons: summer 35-40 degrees and winter 20-30 degrees
characteristics of hot desert soil
- thin, sandy, rocky and generally grey in colour
- very dry and soak up water quickly during rain
- appears crusty as all moisture drawn to surface by evaporation and evaporates
development opportunities in sahara desert
- mining, phosphate mining in Morocco
- energy generation - massive solar farms will be built
- farming - channeling of water allows crops such as wheat and cotton to grow
- tourism - many Star Wars sets filmed in sahara
development challenges in sahara desert
- extreme temperatures making hard for people to farm or mine
- limited water supply, without water mining, farming and tourism not possible
- inaccessibility due to poor infrastructure
what is deposition
when the sea loses energy and drops the material it has been carrying
why does deposition happen
- waves starting to slow down
- shallow water
- sheltered areas
- little or no wind
coastal landforms created by erosion
- headlands and bays
- cliffs and wave-cut platforms
- caves, arches, stacks and stumps
coastal landforms created by deposition
- beaches
- spits
- bars
hard engineering strategies for coastal management
- sea walls
- rock armour
- gabions
- groynes
soft engineering strategies for coastal management
- beach nourishment
- beach reprofiling
- dune nourishment
how is a meander formed
as river makes its way to middle course volume of water and energy increase, later erosion widens river and river flows over flat land develops bends called meanders
what happens in a meander
- as river goes around a bend water is pushed outside which increases speed and erosion (through hydraulic action and abrasion)
- lateral erosion on outside causes undercutting to form river cliff
- water on inner bend is slower causes water to deposit eroded material creating gentle slope of sand
- this build up of sediment is slip off slope or river beach
how is an oxbow lake formed
- erosion makes the neck narrower
- during floods, water takes shortest course across neck
- deposition cuts off original meander forming horseshoe-shaped oxbow lake
how does land use increase the risk of flooding a river
- when an area surrounding a river is built on there is an increase in tarmac and concrete which are impermeable surfaces
- drains and sewers take water directly to river which increases flood risk
how do natural factors increase risk of flooding a river
- relief - a steep valley is more likely to flood than a flatter one because water gets to river quicker
- heavy rainfall - if there is havy rainfall less chance of it being soaked up by soil
- geology - impermeable rocks increase surface run-off
what are factors influencing lag time
- size of drainage basin
- vegetation
- valley side steepness
- soil type
