Natural Hazards Flashcards
How can the risk of tectonic hazards be reduced?
- Monitoring includes using scientific equipment to detect and record physical changes and warning signs of events
- Prediction includes using historical evidence or trends and computer based modelling to predict when an where a hazard may occur.
- Protecting includes increasing the resistance of a population to tectonic hazards by physically designing building which ill withstand tectonic hazard.
- Planning includes identifying and avoiding places that are most at risk as well as having systems in place to prepare in advance.
Typhoon Haiyan Case Study- Primary effects
- 6300 deaths
- 40,00 homes destroyed
- Over 400mm of rain cause widespread flooding
Typhoon Haiyan Case Study - Secondary effects
- Power supplies were cut off for a month in some areas
- flooding causes unstable slopes to become saturated with water resulting in landslides and blocked roads which cut off aid to remote communities
What evidence is there for climate change?
Tree rings reveal the history of a trees growth with each ring representing the trees growth for a single year and the width of the ring showing the growth rate which is dependant on climate
How can we mitigate climate change (reducing cause)?
- Alternative energy sources can be utilised in order to reduce society’s reliance on fossil fuels and lower greenhouse gas emissions. Alternative energy resources include: biomass, geothermal and wind
- Carbon capture and storage is the process of capturing CO2 that would usually be emitted when burning fossil fuels and store it in underground reservoirs.
- Tree planting can be utilised as trees take up CO2 emissions during photosynthesis and they release moisture into the atmosphere to produce clouds that reflect solar radiation
How can we adapt to climate change?
- adapting Agricultural systems by introducing irrigation systems , introducing more flood- resistant crops due to increased flooding as a result of rising sea levels or crops with higher yields, educating farmers and using new tech
- Adjusting to rising sea levels can be accomplished through constructing flood defences such as sea walls or sand dune regeneration. Alternatively, rising sea levels can be combatted through building houses on stilts.
describe the structure of a cyclone.
The central part of the tropical storm is known as the eye which is an area of calm, with light winds, no rain and it contains descending air. Large cumulonimbus clouds surround the eye which is known as the eye wall, with wind speeds of an average 160km per hour.
explain the benefits of using hard engineering strategies to protect the coastline
- hard engineering strategies reflect or minimise the energy of the waves that hits the cliff. For example, a sea wall has a curved face which means it reflects the waves power from hitting a cliff and eroding it
- hard engineering strategies are long-lasting as the structures are typically made out of concrete or wire cages which are resistant against the waves power
explain the formation of a beach
-The formation of the bay means there is an area which is sheltered, this means the waves here have limited energy. The waves are therefore constructive so have a powerful swash that deposits material and a weak backwash, therefore material accumulates forming a beach
explain the formation of headlands and bays
along a discordant coastline there are alternating bands of hard rock and soft rock which are perpendicular to the coast. The soft rock erodes at a faster rate causing the formation of bays whilst the harder rock erodes at a slower rate as it is more resistant forming headland which jut out from the coastline.
explain how river levees are formed
-when a river floods friction with the floodplain leads to a rapid decrease in the velocity of the river therefore it no longer has the capacity to transport material, so deposits it. Large material is deposited closest to the river bank whilst the smaller material is deposited further away meaning the levees are gently sloping.
explain how wave cut platforms are formed?
-The sea erodes the base of a cliff in between high and low tide by mainly hydraulic action and erosion causing the formation of a wave-cut notch. Repeated erosion causes the notch to enlarge into a cave and the overhanging rock becomes unstable. The unsupported rock eventually collapses and the waves backwash removes the material out to sea. This forms a wave cut platform which will retreat continuously after repeated erosions
explain the physical factors that affect flood risk
- the relief of the landscape can increase the risk of flooding as the steeper the gradient of the land the more rapidly surface run-off will enter the river channel
- heavy and prolonged rainfall will saturate the land until the filtration capacity of the soil is exceeded increasing surface run-off into the river channel. If the rainfall is extremely heavy the water will arrive
explain the human factors that affect flood risk
- the land use of an area can increase the risk of flooding as if an area has lots of urbanisation it will mean there are lots of infrastructure and transport routes which are typically made out of impermeable materials like concrete. This means water cannot infiltrate leading to increased surface run off
- if there is increased deforestation then there will be increased flood risk as trees intercept rainwater and absorb water from the soil into the roots. This means that less trees will lead to increased surface run off
explain how river straightening helps to manage the river
river straightening speeds up the water so that larger volumes of water can pass through an area quickly, reducing the chance of flooding
