Paper 1) Hazardous Environments Flashcards
Hazard definition
A natural hazard is a natural events that have the potential to harm people and their property.
Disaster definition
A major hazard event that causes widespread disruption to a community or region, with significant demographic, economic and/or environmental losses, and which the affected community is unable to deal with adequately without outside help.
What is one of the least hazardous places in the world?
-Central Russia
-landlocked - no tropical cyclones
-no active volcanoes present
-low frequency and intensity of tornadoes
-high continentality - no risk from storm surges or tsunamis
What is one of the most hazardous places in the world?
-Philippines
-Country most exposed to tropical storms in the world
-located near the Ring of Fire - prone to earthquakes
-other hazards - typhoons, landslides, floods
Earth’s structure
Crust - the thinnest layer:
-oceanic crust - under the sea - denser, made of basaltic rock
-continental crust - under the land - lighter, granitic rock
Mantel - thickest layer:
-upper: lithosphere, asthenosphere
-lower
Core - 5000C
-inner - liquid iron and nickel
-outer - solid ball of iron and nickel
Convection current
The core heats the magma and it rises. As it rises and cools, it solidifies and sinks down again. The core heats it up again and the cycle restarts.
Ring of fire
-region where many volcanoes and earthquakes take place
-along the rim of the Pacific ocean, near the Philippines, Japan, Mexico, etc.
-home to 452 volcanoes
-75% of the world’s largest earthquakes are found along it
-Japan has 10% of the world’s active volcanoes and has 15 volcanic events every year
Evidence for plate tectonic theory
-continental fit
-biological evidence
-tectonic activity
-geological evidence
Evidence of plate tectonic theory - continental fit
-the matching of large-scale geological features on different continents.
-the coastlines of South America and West Africa seem to match up
Evidence of plate tectonic theory - biological evidence
Many fossils found along the edges of different continents are the same, which suggests that the two continents were joined at some point in the past
Evidence of plate tectonic theory - tectonic activity
There is a large amount of seismic, volcanic, and geothermal activity along the plate boundaries, which defines them clearly.
Evidence of plate tectonic theory - geological evidence
Mountain ranges that link across continents
-Ridges, e.g. mid-Atlantic ridge where plates are separating (sea floor spreading) - produced by lava welling up from between the plates as they pull apart (sea floor spreading)
Types of plate boundaries
-constructive/ divergent
-destructive
-conservative
-convergent
Constructive plate boundary
-also divergent plate boundary
-two plates moving apart from each other
-e.g. Mid Atlantic Ridge - located along the floors of the Atlantic Ocean. Lava wells up from between the plates as they pull apart and solidifies
Earthquakes:
-caused by friction as the plates tear apart
-low magnitude, do not cause damage
-forms shield volcanoes
Destructive plate boundary
-continental plate meeting a oceanic plate
-oceanic plate is denser than the continental plate as they are moved together
-the oceanic plate is forced underneath the continental plate
-Earthquakes - as the oceanic plate submerges under the continental plate - subduction zone - friction builds up
-Volcanoes - the magma collects to form a magma chamber, then rises up through cracks in the continental crust. As the pressure builds up, a volcanic eruption may occur
-Peru-Chile Trench
Conservative plate boundary
-where two plates slide past each other in the opposite or in the same direction but at different speeds
-no volcanic activity
-earthquakes - plates do not pass each other smoothly, the friction between the two plates causes resistance. Pressure builds, the crust can fracture, releasing energy as earthquakes
-e.g. San Andreas fault
Convergent plate boundary
-when two continental plates or two oceanic plates move together and meet
-collision zones
-when two ocean plates move towards each other, layers of sedimentary rock on the sea floor become folded
-eventually, the sedimentary rock appear above sea level as a range of fold mountains
-e.g. The Himalayas - fold mountains
Two types of volcanoes
-composite volcano
-shield volcano
Composite volcano
-usually found at destructive boundaries
-violent, explosive eruptions
-made of alternating ash and lava
-steep slopes as lava is less viscous -pyroclastic flow rather than a lava flow
Shield volcano
-usually found at constructive plate boundaries
-formed by eruptions of thin, runny lava
-eruptions are more frequent but relatively gentle
-gentle slope
-low, wide cone
Super volcanoes
-a volcanic center that has had an eruption of magnitude 8 on the Volcano Explosivity Index (VEI)
-At one point in time it erupted more than 1,000 cubic kilometers (240 cubic miles) of material
Hotspot theory
-volcanoes can be formed away from plate boundaries - hotspots
-caused by weak spots in the crust
-formed by plumes of superheated rock rising very slowly through the mantle, causes the asthenosphere and the lithosphere to melt
-magma rises through weaknesses in the crust and erupts at the earth’s surface
-oceanic hotspots - erupts basaltic lava, huge shield volcanoes
-continental hotspots - viscous, granitic lava, erupts explosively
Causes of earthquakes
Sudden violent shaking of the ground
-plates try to move and become stuck
-pressure builds up because the plates are still trying to move
-when the pressure it released, it sends out huge amounts of energy causing the Earth’s surface to shake violently
Focus definition - earthquake
The point inside the Earth’s crust where the earthquake originates from
Seismic waves definition
-the earthquake’s energy that is released and spread out from the focus
Epicentre definition
Point on the Earth’s surface directly above the focus
Richter scale
-a numerical scale for expressing the magnitude of an earthquake from seismograph oscillations
-10 point scale
-Logarithmic
Mercalli scale
-measures how much damage is caused by the earthquake based on observations
-scale between 1-12
-perception made from observer and the estimation they make based on damage to surroundings
Magnitude vs intensity definition
-The great size or extent of something (earthquakes). Used for the Richter Scale
-Describing the severity of an earthquake in number form. Used for the Mercalli Scale
Advantage of the Richter scale over the Mercalli scale
-Richter scale shows an accurate magnitude no matter the location
-Mercalli scale bases the earthquake’s intensity on the damage done to the surroundings
-if an earthquake is the same magnitude, but at an inhabited or uninhabited area, it is different
-it is objective as it is based on the perception of the onlooker
Seismograph
Used to detect and record the vibration of the earth surface. Its vibrations are shown on display or paper print.
Three actions that can be taken to reduce the impact of earthquakes
-Predict - difficult, but can observe the swelling of the rock, bubbles and gases coming to the surface, notice seismograph to tell if there are shocks and notice animal behaviours
-Protect - design and build structures that are safe and provide protection
-Prepare - authorities - e.g. for evacuation, training emergency services, putting warning systems in place, preparing hospitals, food supply, educating people
Three parts that make up a emergency disaster plan
- Prepare the area for disaster
- Try to save people’s lives and look after the people worst affected
- Aim to get the area back to normal again
What can people do with a few seconds warning
-try to evacuate the building
-look for somewhere safe to go
-Tsunami - get to high ground
-find a place to drop, cover, hold
Remote sensing and GIS
-Remote sensing is the science of obtaining information about objects or areas from a distance, typically from aircraft or satellites.
-Satellite images are increasingly being used.
-Image of the affected area immediately after the earthquake can provide valuable information for search and rescue operations.
-GIS - a computer system that consists of software used to analyze the collected data and hardware that the software would operate in
Earthquake resistant features for buildings
-open areas for people to assemble if evacuated
-building materials are fire-resistant
-to reduce movement: computer controlled weights on the roof
-interlocking steel frame
-steel structure with outer panels flexibly attached
-to prevent falling glass: automatic window shutters
-deep foundations sunk into bedrock to prevent the building’s collapse and provide sturdiness
-rubber shock-absorbers to absorb earth tremors
-use of dampers allows hydraulic pressure to prevent building sway
Protection from earthquakes in less developed countries
-lightweight structures/ walls - subject to smaller forces and less likely to fall when the ground shakes
-small windows - create fewer weak spots in walls
-reinforced walls - with eucalyptus or bamboo
-shock absorbers - tires filled with stone or sand and fastened between floor and the foundation
Nepal - earthquake case study
-April 2015
-7.8 Magnitude
-destructive plate boundary
-Pressure builds up along the fault line as plates ‘stick’ together. This stored energy becomes so great that the plates suddenly give way
-Indian plate jumped forward about 2 metres
Short term impacts of the Nepal earthquake
-over 8500 deaths and around 23000 causalities
-hundreds of buildings destroyed, including schools, businesses, schools and hospitals. Over half a million homes destroyed
-shockwaves from the quake reached neighboring countries
-caused avalanches and landslides in the Himalayas, which caused climbers to lose their lives
-over 2.8 million people displaced or homeless
7 billion US dollars of damage
Long term impacts of the Nepal earthquake
-Many fields and crops were damaged so they lacked food and their livelihoods were destroyed
-People did not have enough money to make or build new homes, so they became homeless
-1.7 million children had been driven out into the open
-Loss of tourist revenue, a major industry in Nepal
-70% of the affected people still live in temporary shelters as they do not have enough money to rebuild
Nepal’s vulnerability to earthquakes - environmental
The geological make-up of the Kathmandu Valley (valley in Nepal) floor can increase the vibration in the case of an earthquake but also lead to soil liquefaction, which causes buildings to sink
Nepal’s vulnerability to earthquakes - sociapolitical
Nepal is multicultural. This cultural diversity also leads to socio-economic inequality. This leads to certain groups systematically excluded from participating in developmental processes
Nepal’s vulnerability to earthquakes - economical
Nepal is one of the poorest countries in the world, more than 50% of the population lives below the poverty line of 1.25 US dollars per day
Short term responses to the Nepal earthquake
-almost 90% of the Nepalese Army were deployed to help, as well as troops from India and a number of aid agencies
-specialist rescue teams used thermal imaging equipment and specially trained dogs to locate people
Long term responses to the Nepal earthquake
-Thousands of Nepalese women and men volunteered to help
-2 months after the earthquake, 56 countries offered to help Nepal. 200 million for housing support, 100 million dollars for public -budget support
-International aid (Japan was one of the biggest donors to Nepal) and NGOs offered extended relief effort
-Government formed the National reconstruction authority to rebuild homes -200000 rupees each for the families who lost their homes
Why do people continue to live in hazardous areas in Nepal at risk of earthquakes
-A lack of education and info may mean that residents are unaware of the real risks, particularly if the hazards occur infrequently
-People may be aware of the risks but decide to live in the area anyway.
-People may be resigned to their fate 0 if they are to be victims, there is nothing they can do about it
-These places are where families have lived for generations and where their friends and family live today - it is where they feel comfortable
-Many people are optimists and think that they will never be a natural disaster victim
-People may be unable to move away from the area, owing to a lack of money, or they worry about not being able to find a job elsewhere
Technology factors that decrease vulnerability to earthquakes
-an alarm system that alerts people to escape from buildings or find somewhere safe
-deep foundations
-evacuation programs
-dampers
-steel structures
Demographic factors that increase vulnerability to earthquakes
-large demography of elderly people, as they are least likely to help themselves or escape
-low income countries, less money to spend on building infrastructure
-densely populated areas - buildings can collapse into each other and cause more damage
-people with disabilities can’t escape from falling buildings
-education level
Hazard mapping
-Choropleth map
-Highly destructive earthquakes often occur in areas that hazard maps predict to be relatively safe.
Rebuilding programmes
-High income countries can afford to rebuild.
-They can move and rebuild towns to less dangerous areas.
Factors affecting vulnerability
-education
-building design
-home preparation
-buildings and settlement location
-housing and population density
-prediction, alarms, evacuation procedures
-search teams, rescue equipment
-medical care, emergency supplies
-economic status
-insurance
-sex, age and health
-aid
Japan tsunami case study
-march 2011
-9 on the Richter scale
-destructive plate boundary
-Tohuku earthquake
What causes tsunami waves
-Most tsunamis are caused by earthquakes at destructive plate boundaries.
-an oceanic plate is subducted into the mantle beneath a continental plate
-causes friction, plates stick
-Energy accumulates
-When the energy exceeds the friction, the plates snaps back into position
-water is displaced, force creates waves that radiate outward in all directions away from their source
Primary effects of the Japan tsunami
-The destruction of thousands of homes
-The flooding of large areas
-Total cost of repair and rebuild was at £185 billion. Over 6% was wiped from the value of shares on the Japanese stock exchange, equivalent to a loss of £90 billion.
Secondary effects of the Japan tsunami
-In Northeast Japan the loss of homes meant nearly half a million people were living in shelters
-The disruption to rail and road links made it harder for rescue teams and equipment to reach places where it was needed, and later it became difficult for families to reunite.
What the Japanese Government did for the 2011 Japanese tsunami
-100,000 people began the disaster relief mission
-Shelters were set up in schools and sports halls for people displaced
-The Japanese government gave the affected supplies
What NGOS did for the 2011 Japanese tsunami
-The Japanese Red Cross mobilized 230 emergency teams to the worst affected areas
-Mercy Corps provided relief items - tents, tarps, blankets, etc
-Shelterbox, a international disaster relief charity sent 1500 boxes to Japan containing a tent, sleeping bags, gloves, cooking equipment, tools, and toys.
International help - 2011 Japanese tsunami
-Many countries, including the UK, sent teams to help with search and rescue
-Operation USA began working to address needs for material aid with a focus on shelter and medical supplies
-Staged disaster supplies were prepped and dispatched from OpUSA’s port of Los Angeles warehouse
Volcanoes measured by
-volcanic explosivity index (VEI)
-logarithmic scale
Advantages of living in a volcanic area - Iceland
-Geothermal energy which can be used to generate electricity for Icelandic homes and industries. Where magma is close to the surface, groundwater turns to steam. This can be used to drive a turbine to generate electricity cheaply and sustainably.
-Geothermal heating. It is predicted in the future the number of homes heated by geothermal heating will be 92%. Water from hot springs are piped to homes.
-tourism and recreation. There are nice views in Iceland, with waterfalls, basaltic cliffs, crater lakes, volcanic cones, etc.
Montserrat volcanic eruption case study
-June 1997
-4 on the VEI
Short term impacts - Montserrat case study
-ash, smoke in the air
-2000 people left the island the day the volcano started erupting
-20 people killed
-homes were destroyed, transport and communication links in the more uninhabited parts of the island
-people lost their possessions
-fires spread to gas pipe explosions damaging woodland
-landslides triggered with river water mixing with ash, mud and lava to form lahars
-forest fires caused by pyroclastic flow
Long term impacts - Montserrat case study
-many people has to be rehoused, sometimes in refugees camps of make-shift tents that became permanent
-disease spread such as silicosis and respiratory illness
-water pipes damaged, water supplies contaminated
-over half the population left the island and never returned
-income lost due to a focus on rebuilding and repairing damage
-pressures rose financially and increased crime rates
-tourism industry suffered
-important natural landmarks were lost with flora and fauna being badly impacted/ destroyed
-a layer of ash and mud covered the southern side of the island, making it uninhabitable
Responses to Montserrat earthquake
-£41 million given in aid by the British government
-money was given to individual to help them abroad
-the MVO (Montserrat Volcano Observatory) was set up to study the volcano and provide future warnings
-risk assessment done to help islanders understand which areas are at risk and reduce problems in future
How can volcanoes be monitored
-are unpredictable, scientist can use:
-seismometer - used to measure earthquakes occurring near an eruption
-tiltmeters and GPS satellites - these devices monitor any changes in landscape. Volcanoes tend to swell near an eruption
-Spiders - monitoring gases escaping from a volcano using robots called Spider that monitor the release of sulphur dioxide near an near an eruption
-satellite imagery - measuring temperature, we can see when volcanoes become hotter when magma starts to rise through the main vent
-historical events - looking at the past history of eruptions - scientists can identify patterns of activity
Characteristics of tropical cyclones
-starts between 5 and 30 degrees N and S of latitude
-seawater at least 26 degrees
-118km/h
-strong winds, 10-12km above the earth
-they blow east to west (due to the earth’s spin) because of trade winds around the equator, spinning away from the equator
-peak in august as the water warms slower than land
How do tropical cyclones formed
- Once the ocean reaches at least 26 C, the warm air rises quickly, causing areas of low pressure
- As the air continues to rise quickly, it draws more moist air up from above the ocean, leading to strong winds
- Rapid, rising, warm air spirals upwards, cools, condenses and large clouds form, producing heavy rainfall
- In the eye cold air sinks, and the conditions are calm and dry
- When cyclones reach a land surface, they begin to lose energy and die out as they are not receiving heat energy and moisture from the oceans, which is needed to drive them
Tropical cyclones
A very powerful low-pressure weather system which results in strong winds and heavy rainfall
Coriolis force
Global winds blow from high to low pressure. The earth is constantly rotating and deflects winds to the right in the Northern Hemisphere and to the left in the southern hemisphere
-does not take place on the equator
What scale is used to measure hurricane winds
The Saffir Simpson scale
How are tropical cyclones monitored and tracked
-through GID and satellite imagery
-used to spot where they originate, which helps forecaster to plot where they will go
-40% of the world’s population live 100km distance of the sea, so its important they are monitored
When do tropical cyclones become weaker
-when it reaches land it loses its energy as it has no fuel source (warm water)
-when it moves to areas of colder water (below 26.5)
-when it runs into other weather systems where winds are blowing in different directions
How countries prepare for tropical cyclones
-3 day forecast track (weather forecast)
-satellite imagery
-early warning system
-tropical cyclone shelters and evacuation strategies
-storm surge barriers/ embankments
-preparing emergency pack/ government supplies
How countries prepare and respond to tropical cyclones
-prediction
-planning
-aid
-education
-protection
How countries prepare and respond to tropical cyclones - prediction
-constant monitoring and weather forecasting - helps to give advanced warming of a tropical storm
-ships and buoys record water temperatures and air pressure, sending results to shore
-satellite tracking - used to track tropical cyclone. Easy to spot satellite images as they use visible and infrared images to see if a storm grows and where it moves to
-computer models - use the atmospheric pressure data, seawater temperature and information on wind speeds. Modelling programmes combines this information to estimate likely tracks of tropical cyclones how severe storms might become and where they might go
-difficult to predict - equipment is expensive and not affordable for many developing countries like the Philippines
How countries prepare and respond to tropical cyclones - planning
-Emergency services can train and prepare for disasters. This reduces the number of people killed.
-Evacuation routes in risk zones to get people away from storms quickly
-emergency services and planning evacuation can be very expensive. Often the poorest people even in developed countries do not have access to a car or cannot afford to move. E.g. New Orleans, hurricane Katrina
How countries prepare and respond to tropical cyclones - aid
-government or organisations - reduce impacts by providing basic needs
-charities such as DEC (Disasters Emergency Committee) and ShelterBox provide aid to nations affected by tropical cyclones. ShelterBox provides emergency shelter and non-food supplies
How countries prepare and respond to tropical cyclones - education
information about tropical cyclones is broadcasted daily on tv, radio, internet, social media
-people are encouraged to buy the right supplies and make a family disaster plan for reaching shelter
-in the US hurricane preparedness week is held every may to let people know what to be in a hurricane
-in developing countries, a nationwide education programme may not be practical. Funding limited and fewer people would have access to tv or the Internet
How countries prepare and respond to tropical cyclones - protection
-embankments, river levees, flood walls - defend settlements from storm surges
-can take a long time to plan and develop as well as being extremely costly so they only be afforded by developed countries
-walls and roofs of houses can be strengthen so wind cannot damage them so easily
-houses at serious risks of flooring could be built on stilts
-projects restoring lost wetland can be put in place so that trees such as mangroves absorb storm energy
-belts of trees can be planted to shelter coastal homes from the wind
Mozambique tropical cyclone case study
-2019
-cyclone Idai
Short term impacts of Mozambique tropical cyclone case study
-homes destroyed
-infrastructure damage
-flooding
-crops destroyed
-1.85 million in need of assistance
-1 million without electricity
-50 health units destroyed
-governments have less well developed emergency services, it is more difficult to get help
-many emergency workers are also affected by the disaster and may be unable to perform their duty
-fewer people have insurance or savings, so they don’t have the resources to rebuild their lives
Long term impacts of Mozambique tropical cyclone case study
-Mozambique has a high HIV prevalence, with damage to the health services, so they can’t get medication
-isn’t enough safe drinking water, sewage systems overflow and contaminate drinking supply and people’s hygiene and sanitation suffer in the aftermath of any natural disaster - increases diseases
-mosquito borne diseases like malaria and dengue are always present. More cases are likely to occur after flooding because of increase numbers of mosquitoes
Short term responses - Mozambique tropical cyclone case study
-The highest possible alert was raised by the government three days before the cyclone struck, telling people to evacuate threatened areas
-South African air force and Indian army, which happened to have a ship in the area, drove the initial rescue effort
Reasons Mozambique is vulnerable to tropical cyclones
-high relief that flows down to the coast. Rivers are flooded due to heavy rainfall and will flow into Mozambique
-most people live on the coast which is close to the sea and at risk to storm surges
-most people work in agriculture - when the storm affects and destroys crops, more people are affected
-large amounts of deforestation - trees prevent flooding
-people who get HIV is increasing over the years - health centres are destroyed, so people can’t get treatment and more people get HIV
-Mozambique GDP per capita is much lower than the world average - less money to rebuild their homes after a cyclone occurs
Tsunami case study - Indian Ocean Tsunami
-December 2004
-9.2 magnitude
Tsunami
A series of ocean waves caused by earthquakes or undersea volcanic eruptions
How tsunamis form
-an earthquake occurs and one section of the crust is thrust upwards
-water is displaced, creating a wave which spreads out
-as the wave approaches the shore, the wave height increases and the wave length shortens
How do tsunamis increase in height
-out in the depths of the ocean, tsunami waves do not dramatically increase in height
-as waves travel inland, they build up to higher heights as the depth of the ocean decrease, speed slows
-as the wave moves closer to the shore, it grows taller as the as the ocean becomes shallower
Common features of tsunami proof buildings
-raised position above the ground - stilts
-strong/ reinforced base
-shatterproof windows
