challenges of natrual hazards Flashcards
Noto, Japan earthquake:
case study
1st January 2024 4:10pm 7.6 Richter scale
primary effects:
-208 deaths
-600 people injured
-Damage to 15 fishing ports
secondary effects:
-1-6m tsunami
-extensive coastal flooding
-sporadic fires
immediate response:
-62,000 people evacuated due to tsunami warning
-cranes and diggers remove rubble
-phone alert
long term response:
-food/hot meals for people
-$28m government disaster fund
Turkey/Syria earthquake:
case study
(LIC) 6th February 2023 3:17am 7.8 richter scale
primary effects:
-55,000 deaths
-130,000 injured
-26 million affected
-164,000 buildings destroyed or severely damaged
secondary effects:
-psychological impacts from experiencing the event
-estimated 2.7 million people made homeless
-one in 3 children lost their homes
immediate response:
-digging with hands
-sniffer dogs
long term response:
-international aid
-volunteers
Typhoon Haiyan, Philippines:
case study
November 2013
category 5
314km/hr winds
280mm rain in 12 hours
primary effects:
-at least 6340 killed
-5m storm surge
-90% buildings in Tacloban destroyed
-crops destroyed
secondary effects
-130,000 houses destroyed, 4.2 million homeless
-$14 billion of damage
-water polluted
-looting
immediate response:
-1069 emergency shelters
-3,316,500 people outside providing aid
long term response:
-UN appeal raised $480 million
-people betted educated
Somerset floods:
December 2013 – February 2014
SW England
This is a very low-lying area, which experiences winter flooding. Wettest January on record. 350mm of rain fell in January and February, about 100mm above average
Social Effects:
•Residents evacuated to temporary accommodation for months
•600 homes flooded across Somerset Levels.
•16 farms evacuated.
•Villages such as Moorland and Muchelney cut off. This affected people going to school, shopping etc.
Economic effects:
•Estimated £10 million damage by Somerset County Council.
•Local roads cut off by floods.
•Over 1000 livestock evacuated.
•Bristol to Taunton Railway line closed at Bridgwater.
Environmental effects:
•Floodwaters heavily contaminated with sewage, oil and chemicals.
•Huge amounts of debris had to be cleared. Stagnant water had to be re-oxygenated before being pumped back into the rivers.
Management strategies
•A £20 million Flood Action Plan was launched by Somerset County Council.
•8km of the River Tone and River Parratt were dredged to increase the capacity of the channel (March, 2014)
•By 2024 a tidal barrage at Bridgwater is being considered.
what is a natural hazard?
a natural event which has the potential to threaten life and property
what are the types of hazard?
-Geophysical
-hydro meteorological
what is a geophysical hazard?
a hazard caused by earth processes and can be tectonic or geomorphal (e.g weathering)
what are hydro meteorological hazards?
hazards caused by water of weather patterns
whats are examples of a Geophysical hazard?
-tsunami
-earthquake
-volcanic eruption
what are examples of a hydro meteorological hazard?
-hurricane
-tropical storm
-flood
what are the 3 factors that affect risk?
-capacity to cope
-level of vulnerability
-magnitude of hazard
what is capacity to cope?
this refers to a community’s ability to absorb the effects of a hazard, response and recover.
generally HIC’s such as Japan have a high capacity to cope whilst poorer LIC’s don’t
what is level of vulnerability?
this refers to how likely the people who live in an area are affected by the hazard.
people in the uk are not vulnerable to volcanic eruptions as there are no active volcanoes in the uk. people who live in Haiti are very vulnerable to earthquakes as they live on a plate boundary.
what is magnitude of the hazard?
this is the size/ strength of the hazard.
it could be that the tropical rotating storm is a category 5 or an earthquake is 9.0 on the richter scale
what is a drought?
when rain is 50% than the 3 month median
risks:
-wildfires
-heat waves
-crops cant grow
-hunger and dehydration
- animals die, people die
what are floods?
these can be costal, river or flash floods causes by precipitation, storm surges and sea level rise
risks:
-housing destroyed
-loss of land
-people evacuated
what are earthquakes?
a sudden violent shaking of the ground, typically causing great destruction, as a result of movements within the earths crust or volcanic eruptions.
risks:
-housing destroyed
-ground not easily fixed
how do tectonic plates move?
- convection current
- currents in the mantle which takes heat from the core and causes it to rise and fall
(like water boiling)
2.slab pull
- when gravity pulls tectonic plates down into the mantle
oceanic crust:
-denser
-sinks
-can be renewed and destroyed
continental crust is:
-less dense
-cant sink
-cant be renewed or destroyed
what are the 4 layers of the earth?
-crust
-mantle
-outer core
-inner core
what are constructive plate boundaries?
- when 2 plates move apart
- magma forces its way up through the cracks
- forms shield volcanoes due to thin lava
- can form new land
located example: Atlantic ridge
what are destructive plate boundaries?
- when 2 plate boundaries collide
- oceanic plate sub-ducts beneath the continental plate
- sinking plate creates new magma, as the rock melted down gas is released and escapes back into the atmosphere through a composite volcanoe
located example: Nazca ans south America border
what is a conservative plate boundary?
-plates slide past each other
-they tend to get stuck and eventually the build up of pressure causes them to be released
-the sudden release of pressure causes an earthquake
-crust is neither made or destroyed
located example:
-California
what are the primary effects of a hazard?
the immediate effect of the hazard, caused directly by it e.g water piped ruptured
what are the secondary effects of a hazard?
the after effects that occur as an indirect effect of the hazard on a longer time scale e.g disease spread
benefits of living in areas at risk:
Iceland
-hot water from within the Earths crust provides heat and hot water for nearly 90% of all buildings in Iceland
-volcanic rocks are used for construction
-tourism
-naturally occurring hot water
4 ways to reduce the risk of natural hazards:
-monitoring
-prediction
-protection
-planning
what is monitoring?
using scientific equipment to detect warning signs of events such as volcanic activity
Earthquakes: seismometers, tells strength and duration
Volcanoes: monitoring of seismic activity
what is prediction?
using historical evidence and monitoring, scientists can make predictions about when and where a tectonic hazard may happen
Earthquakes: general location, general time
Volcanoes: tilt meters, remote sensing
what is protection?
identifying and avoiding places most at risk
shock absorbers
spraying water
what is planning?
designing buildings that will withstand tectonic hazards
conditions at 0°:
-low pressure
-wet and windy
-hot
conditions at 30°:
-high pressure
-hot
-dry
conditions at 60°:
-low pressure
-mild
-wet and windy
conditions at 90°:
-high pressure
-cold
-dry
how are tropical storms formed?
This warm air rises rapidly, drawing more air and large volumes of moisture from the ocean, causing strong winds. The rising air will cool and condense to form tall cumulonimbus clouds – this releases latent heat, which is energy that is released without a change in temperature, which powers the tropical storm.
describe and explain the distribution of tropical storms.
tropical storms are located in between the tropics. they are found here because to form they have to warm waters above 26.5°c with extreme low pressure as warm air rises. They also don’t form exactly on the equator as it doesn’t feel the spin of the earth (Coriolis effect)
possible natural causes of climate change:
volcanic activity - when volcanoes erupt they release sulphur dioxide and ash
solar flares - bursts of heat from the sun
orbital change - natural variations of the earths orbit and tilt circular and oval
human causes of climate change:
deforestation - leaves are burned, doesn’t release oxygen
burning fuels - release co2 and other greenhouse gases
agriculture - livestock produce a large amount of methane
what is mitigation?
refers to actions and policies that are meant to delay,reduce of prevent climate change
what is adaptation?
refers to policies and actions which are designed to reduce existing impacts of global warming
what are examples of mitigation?
carbon capture & recapture - taking co2 out of the atmosphere, like an artificial tree
Alternative energy sources - using renewable energy sources
Afforestation - increases the amount of oxygen
Examples of Adaptation
change in agricultural systems - educating farmers in water harvesting techniques
managing water supply - some areas are using desalination to recover freshwater from oceans
reducing risk from sea level rise - building houses on stilts
Evidence for climate change:
ice and Sediment Cores
• Ice sheets are made up of layers of snow, one per year. Gases trapped in layers of ice can be analysed. Ice cores from Antarctica show changes over the last 400 000 years.
Remains of organisms found in cores from the ocean floor can by traced back 5 million years.
Pollen Analysis
• Pollen is preserved in sediment. Different species need different climatic conditions, so this is a record of past climate.
Tree Rings
• A tree grows one new ring each year. Rings are thicker in warm, wet conditions
• This gives us reliable evidence for the last 10 000 years.
