The challenge of natural hazards Flashcards
What increases the risk of natural hazards?
- Urbanisation
- Poverty
- Farming
- Climate change
What are the two types of crust?
- Dense, thin oceanic crust
- Less dense, thicker continental crust
trWhat is the structure of the Earth?
Crust
Mantle
Outer Core
Inner Core
What is the distribution of volanoes?
- Most volcanoes occur in belts along plate margins (Pacific RIng of Fire, Mid-Atlantic Ridge)
- Some occur a hot spots where the crust is thin and magma breaks trough the surface (Hawaiian Islands)
What is a constructive plate margin?
The two plates move apart and magma forces its way to the surface
- as it breaks the crust it causes mild earthquakes
- broad and flat shield volcanoes (Mid-Atlantic Ridge)
What is a destructive plate margin?
- Two plates move towards each other
- The dense oceanic plate is subducted beneath the less dense continental plate
- Friction causes strong earthquakes
- The sinking oceanic plate creates sticky, gas rich magma
- steep-sided composite volcanoes
What is a conservative plate margin?
- Two plates move past each other at different rates
- Friction between the plates build stress and trigger earthquakes when they slip
- No magma so no volcanoes
Where, what magnitude and when did the Syrian/Turkey earthquake occur?
Southern Turkey near norther border of Syria, 7.8 earthquake, 6th February 2023
What was the cause of the earthquake?
- The East Anatolian Fault is a strike slip fault where the Anatolian and Arabian Plate slid past each other horizontally
- sudden stress release which was built up along the fault line over time
- the movement caused a rupture in the Earth’s crust, releasing massive energy and resulting in severe ground shaking
What were the primary effects of the earthquake?
- Building collapse
- Economic cost
- Infrastructure damage
- Injuries
- Loss of life
How many people were killed, injured and displaced? Turkey/Syria
50,000 killed
107,000 injured
thousands displaced
How many buildings were destroyed? Turkey/Syria
6650
What was the economic cost of the Turkey/Syria?
$84.1 billion
$34.2 billion physical damages
$5.2 billion in Syria
What were secondary effects of the Turkey/Syria?
Aftershocks
Economic impact
Fires
Homelessness
Health crisis
What magnitude were the aftershocks? Turley/Syria
7.5 magnitude aftershocks
What were the secondary economic impacts? Turley/Syria
Several businesses were destroyed
Cost billions of dollars to rebuild
How many people were left homeless? Turley/Syria
1.5 million people in Turkey
5.3 million people in Syria
Where was the fire in Turkey/Syria?
Iskenderun port led to significant damage and disruption in rescue and relief efforts
How was a secondary effect a health crisis?
measles and tetanus
- collapse of hospitals and health centres
- outbreaks of diseases due to poor sanitary conditions
- outbreaks of food and water-borne diseases
What were the immediate responses of the Turkey/Syria earthquake?
Rescue Operations
Local Business contributions
Emergency Aid
International Assistance
Tell me about the rescue operations in Turkey/Syria
Local people began to search for survivors in the rubbles.
Teams from Turkey and international organisations mobilised quickly, sniffer dogs used
Tell me about the local business contributions in Turkey/Syria
Turkish private sector contributed over $11 million in in-kind donations which included essential supplies.
Other Turkish businesses also assisted with accommodation.
Tell me about Emergency aid in Turkey/Syria
Red Cross, MSF, Unicef: food, water, blankets, medical supplies
Tell me about international assistance in the Turkey/Syria earthquake
UN launched significant financial appeals to aid the affected regions.
Issued a $1 billion to assist over 5 million people in Turkey
A $397 million appeal in Syria
What were the long term responses of the Turkey/Syria earthquake?
- Reconstruction - World Bank approved $1billion
- Economic recovery
- Psychological - mental heath support services
- Preparedness and mitigation
How are Turkey/Syria using preparedness and mitigation as a long term response?
Updating building codes
Conducting public awareness campaigns
Improving emergency response systems
What magnitude, whereabouts and when did the Japan earthquake happen
9.0, Japan’s Northeast coast about 400km from Tokyo, March 11 2011
What caused the Japan earthquake?
The Pacific Plate (oceanic) was subducted by the Eurasian plate forming a subduction zone to the east of Japan - destructive plate margin
How much energy was released from the Japan earthquake?
600 million times the energy of the Hiroshima nuclear bomb
What were the primary effects of the earthquake? Japan
Ground shaking
Landfall - some coastal areas experience land subsidence as the earthquake dropped the beachfront in some places by more than 50cm
What were the secondary effects of the earthquake? Japan
- Tsunami
- Deaths
- Injuries
- Economic loss
- Displacement
- Damage
- Blackouts
- Transport
- Nuclear crisis
How many deaths in the Japan earthquake?
16,000-20,000
How many people were injured? Japan
26,152
What was the nuclear plant that was damaged?
Fukushima Daiichi nuclear plant
What was the economic loss of the Japan earthquake?
$235 billion
How many people were displaced in the Japan earthquake?
340,000 people
Tell me some statistics on the numbers of buildings damage in Japan
332,000 buildings
300 hospitals damaged
25 railways
How many house holds faced blackouts in the Japan earthquake?
4.4 million
What was the name of the railway that got damaged in the Japan earthquake?
Tohoku Expressway
What were the immediate responses of the Japan earthquake?
- Tsunami warnings + predictions - tsunami warning 3 minutes after the earthquake
- Search + rescue operations so 100,00 members of the Japan Self Defence Force
- Radiation protection measures - 20 km evacuation zone
- International assistance - US military, South Korea, China, New Zealand
- Access and evacuation
- Health monitoring
What were long term responses to the Japan earthquake?
- Reconstruction policy and budget of 23 trillion yen for recovery over 10 years
- Coastal protection measures - seawalls and breakwaters designed for 150 year recurrence interval of tsunamis
- Transportation and Infrastructure Repair - reopening of Tohoku Expressway by the 24th March and restoration of runway at Sendai airport by 29th March
- Utility reconstruction
Why do people live at risk from tectonic hazards?
- Rare so not huge threat
- Earthquake resistant buildings reduce risk
- effective monitoring of volcanoes and tsunami waves allow evacuation warnings
- Bring benefits such as fertile roils, rich mineral desposits and hot water
How much of Iceland’s electricity is from geothermal?
25%
What are the volcanic rocks in Iceland used for?
Road and building construction
How can risk from tectonic hazards be reduced?
- Monitoring
- Prediction
- Protection
- Planning
Tell me about the monitoring of earthquakes and volcanoes
Earthquakes: occur without warning generally but microquakes before main tremor
Volcanoes: remote sensing - satellites detect heat increases, seismicity - seismographs record microquakes
Ground deformation - laser beams measure changes in the shape of the ground
Tell me about the prediction of volcanoes
Volcanoes: accurate predictions
Earthquakes: accurate predictions impossible due to lack of clear warning signs but historical records
Tell me about the protection of volcanoes and earthquakes
Volcanoes: earth embankments and explosives to successfully divert lava flows (Mt. Etna, Italy)
Earthquakes: earthquake drills help keep people alert and prepared but earthquake-resistant construction is better
Tell me about the planning of volcanoes and earthquakes
Volcanoes: risk assessment and hazard mapping to identify areas to practise evacuation or restrict building
Earthquakes: risk assessment and hazard mapping to identify areas to protect buildings and infrastructure
What is global atmospheric circulation?
- sinking air creates high pressure, and rising air creates low pressure
- surface winds move from high to low pressure, transferring heat moisture from one area to another
- these winds curve due to the Earth’s rotation and change seasonally as the tilt and rotation of the Earth causes relative changes in the position of the overhead sun
Why is it cloudy and wet in the UK?
- Cloudy and wet in the UK because 60 degrees North is close to where cold polar air from the North meets warm subtropical air from the south. These surface winds from the south-west usually bring warm and wet weather because rising air cools and condenses forming clouds and rains
Why is it hot and dry in the desert?
Most deserts are found at about 30 North and South where sinking air means high pressure, little rain, hot daytime temperatures and very cold nights
Why is it hot and sweaty at the Equator?
Low pressure marks where the Sun is directly overhead. Hot, humid air rises, cools and condenses, causing heavy rain - hence the tropical rainforests
What is a tropical storm and where do they form and what conditions does it have to be for them to form?
Huge storms clouds that form 5-15 North and South of the Equator
- ocean temperatures above 27 (26.5) degrees Celcius
- the spinning Coriolis effect of the Earth’s rotation is very high
- intense heat and humidity makes the air unstable
How do tropical storms form?
1) Warm ocean air rises at a temperature above 26.5 degrees Celcius
2) the water evaporates to rise which forms clouds and thunderstorms. There is low pressure at this point
3) At 5-15 degrees North and South of the equator, the Coriolis effect occurs where Coriolis forces to spin the storm creating the calm eye
4) the prevailing winds drift the storm over the ocean surface, gathering strength as it picks up more and more heat energy
How does climate change affect tropical storms?
- sea surface temperatures in the Tropics have increase by 0.25-0.5
- tropical storms may extend into the South Atlantic
- tropical storms may become more powerful
- in the North Atlantic, hurricane intensity has risen in the last 20 years
What was the storm in Mozambique called?
Cyclone Idai
What category, causes, where and when did cyclone Idai occur?
14-15 March 2019, storm cell brought heavy rains to Malawi before heading out to Mozambique
Category 2, 115mph, 150mm of rain in 24hrs
Then swept up inland and onto Zimbabwe
How many people were killed in Mozambique?
1300
How many people were affected by the cyclone
3 million
What percentage of Beira was destroyed?
90%
How many homes did the flash flooding destroy?
600 homes
How many hospitals were damaged?
17
What were the secondary effects of cyclone Idai?
- several rivers overflowed 3000km^2
- outbreaks of cholera with over 4000 cases in Beira alone
- over 700000ha of crops were destroyed so food shortages
- two hydro electric power plants in the Shire River were damaged
What were the immediate responses to Cyclone Idai?
- Over 140 evacuation centres set up to cope with 125 000 displaced people
- In Malawi, a State of Emergency was declared
- UN helicopters dropped food and volunteers working for charities such as the Red Cross supplied emergency provisions
- UK government provided £18 million
- WHO provided 900,000 cholera vaccinations
What were the long term responses to Cyclone Idai?
- Improvements were made to the early waning system to increase awareness and preparedness
- Dutch engineers helped restore water supplies and strong pre-disaster WASH campaign in rural areas
- ‘Build Back Better’ to restore buildings and 90,000 cyclone survivors were relocated to 66 ‘permanent’ shelters
How can tropical storms be monitored and predicted?
Satellites, radar, weather charts
Computer programs analyse the data and predict the track of a storm and its likely impacts
How can countries be protected from tropical storms?
Reinforced walls, roofs and window shutters
Where is Somerset?
South West England
What were the causes of the Somerset Level Floods
- Sequence of south-westerly depressions brought record rainfall in January and February
- High tides and storm surges swept water up the rivers from the Bristol Channel preventing normal flow
- Rivers, clogged with sediment had not been dredge for 20 years
What were the impacts of the Somerset Level floods?
- over 600 houses flooded and 16 farms evacuated
- villages cut off - disrupting work, schools
- 14 000ha of farmland flooded and 1000 livestock evacuated
- power supply, roads and railways cut off
- floodwaters contaminated with sewage, oil and chemicals
What was the estimated damage of the Somerset Levels floods?
£10 million
What were the immediate responses to the Somerset floods
- Huge media interest was generated
- Cut off villagers used boats for transport
- Community groups and volunteers gave invaluable support
What were the long term responses to the Somerset floods?
- £20 million Flood Action Plan
- 8km of Rivers Tone
- River banks raised and strengthened
- Possible tidal barrage at Bridgwater by 2024
Name some evidence that UK weather is becoming more extreme
- 2003 Heatwave
- 2007 Floods
- 2010 heavy snow
- 2015/16 floods
What are recent evidence for climate change?
- shrinking glaciers and melting ice
- rising sea levels
- seasonal changes (trees flowering and bird migration is advancing)
What are the 3 main natural causes of climate change?
- Orbital changes
- Solar activity
- Volcanic activity
What are the Milankovitch cycles
- Eccentricity - every 100 000 years or so the orbit changes from almost circular, to mildly elliptical (oval) and back again
- Axial tilt - every 41 000 years the tilt of the Earth’s axis moves back and forth between 21.5 and 24.5 degrees Celcius
- Precession - over a period of around 26 000 years the axis wobbles from one extreme to the other
How does solar activity cause climate change?
The surface of the Sun has dark patches called sunspots which mark short term regions of reduced surface temperature and are usually accompanied by explosive, high energy solar flares increasing heat output
Over a period of around 11 years
How does volcanic activity affect climate change?
Volcanic ash can block out the Sun, reducing temperature on the Earth
