Geog Paper 1
Define natural hazard
a naturally occurring event that poses a threat to people, property or the environment
Name 2 types of natural hazard
Tectonic
Climatic
What factors affect natural hazard risk? Give 4
- Frequency
- Population density
- Urbanisation
- Climate change
State the plates tectonics theory
Earth's outer layer, the lithosphere, is broken into large, rigid plates that move relative to eachother
Describe the continental crust
- Older, lighter and cannot be destroyed
Describe the oceanic crust
Denser, can be subducted and is constantly being destroyed and replaced at plate boundaries
Where do volcanoes and earthquake activity often occur?
In similar places in narrow zones of activity. These zones include:
- The Pacific Ring of Fire
- The Mid-Atlantic Ridge
- Southern Europe
What is the Pacific Ring of Fire?
Where over 450 of the world's active and dormant volcanoes are located, and where about 90% of all earthquakes happen
What physical processes occur at destructive plate boundaries?
- The plates move towards one another which can cause earthquakes and volcanoes
- As the plates collide, the oceanic plate is forced beneath the continental plate (this is known as subduction) and results in the formation of an ocean trench
- When the plate sinks into the mantle it melts to form magma.
- The pressure of the magma builds up beneath Earth's surface
- Th magma escapes through a composite volcano and erupts violently
What physical processes occur at constructive plate boundaries?
- The plates are moving apart from one another
- The magma in the mantle rises up to make a new crust
-The movement of plates over the mantle can cause earthquakes
- Rising magma can also create shield volcanoes
What physical processes occur at conservative plate boundaries?
- The plates slide past each other in opposite directions, or in the same direction at different speeds
- As the plates try and move, friction occurs and the plates become stuck
- Pressure builds up because the plates are still trying to move
- When pressure is released it sends out huge amounts of energy, causing an earthquake
Give 5 reasons why people continue to live in areas at risk from a tectonic hazard
- Volcanic ash results in fertile soil
- Availability of geothermal energy
- Lower house prices
- Sentimental value
- Sulfur extraction from volcanoes
What is a pressure belt?
Regions on Earth's surface characterized by either high or low atmospheric pressure, which influences weather patterns and wind circulation
Describe the global distribution of tropical storms
Tropical storms primarily occur in tropical regions between 5 and 30 degrees north and south of the equator
Describe the relationship between tropical storms and the Hadley cell
This is a major circulation pattern in the tropics where warm, moist air rises, cools, condenses and creates the low pressure zone of the ICTZ
Describe the relationship between tropical storms and the ITCZ
This is a belt of low pressure around the equator where trade winds from the north and south converge, causing uplift and heavy rainfall
Describe the relationship between tropical storms and trade winds
The trade winds, which blow from subtropical high-pressure zones towards the equator, are a key component of the Hadley cell and provide the initial impetus for the formation of tropical storms
Describe the relationship between tropical storms and the Coriolis Effect
This effect, caused by Earth's rotation, deflects the rising air, creating a swirling motion that initiates the rotation of tropical storms
What causes tropical storms?
A combination of:
- Warm ocean water: provides energy and moisture for the storm
- Low wind shear: allows the storm to intensify
- The Coriolis effect: gives the storm its spiral shape
Describe the formation of a tropical storm
1. Warm ocean water (at least 27 degrees celcius) heats the air above it, causing it to rise rapidly creating an area of low pressure
2. Air from surrounding areas rushes in to fill the space left by the rising air, leading to strong winds
3. As the rising air continues to climb, it cools and the water vapor condenses into clouds, releasing latent heat
4. The cumulonimbus clouds become large and release heat, further driving the storm
5. The coriolis effectt occurs, forming a cyclone
6. In the center, cold air sinks, creating a calm, clear area known as the eye of the storm
How may climate change affect the distribution of tropical storms?
- Warmer ocean temps meaning more succeptability to the formation of tropical storms in areas they were previously uncommon
How can monitoring reduce the effects of a tropical storm?
Satellites and radar systems track the formation, movement and intensity of tropical storms, providing real-time data
How can prediction reduce the effects of a tropical storm?
Computer models use data from monitoring to predict the storm's path, allowing for early warnings and evacuation plans
How can protection reduce the effects of a tropical storm?
- Building Codes: Enforcing strict building codes ensures structures can withstand high winds and flooding
- Coastal defences: Sea walls, levees and storm surge barriers protect coastal communities
- Reinforced structures: Strengthening windows, doors and roofs reduced damage from flying debris
How can planning reduce the effects of a tropical storm?
- Evacuation plans: Well-coodinated evacuation plans ensure safe and efficient displacement of people
- Disaster supply kits: Preparing essentials like food, water and first-aid kits ensures preparedness
- Community awareness: Education and training programs inform residents about storm risks and appropriate actions
What types of weather hazards are common in the UK? Give 6
- Rain
- Wind
- Heatwaves
- Thunderstorms
- Hailstorms
- Snow
Give 3 pieces of evidence that the weather in the UK is becoming more extreme
- A rise in average temperatures
- Increased intensity of extreme weather events like heatwaves and storms
- Shifts in percipitation patterns including drier summers and wetter winters
Name possible causes of climate change including natural factors and human factors
- Natural factors: orbital changes, volcanic activity and solar output
- Human factors: use of fossil fuels, agriculture and deforestation
Give 3 examples of climate change since the beginning of the Quaternary period to present day
1. Glacial-interglacial cycles: Repeated periods of cold and warm periods which have dramatically altered sea levels, landscapes and ecosystems
2. Rapid warming and sea level rise: Following the last glacial period, Earth experienced a rapid warming which caused sea levels to rise leading to flooding and the formation of coastal features
3. Modern climate change: Human activities have led to a rapid increase in greenhouse gas concentration in the atmosphere resulting in global warming
Managing climate change involves both 'mitigation' and 'adaptation', define both of these terms
Mitigation - reducing causes
Adaptation - responding to change
Give examples of mitigation and adaptation when responding to climate change
- Mitigation: renewable energy production, carbon capture, planting trees and international agreements
- Adaptation: change in agricultural systems, managing water supply, reducing risk from rising sea levels
What are producers in an ecosystem?
- The foundation of an ecosystem
- Use photosynthesis to convert energy into food (self-feeders)
What are consumers in an ecosystem?
- They obtain energy by consuming producers or other consumers
- E.g. herbivores, carnivores, omnivores
What are decomposers in an ecosytem?
- Decomposers like fungi and bacteria break down dead organic matter including dead plants and animals
- They recycle nutients back into the environment making them available for producers to use
What is 'nutrient cycling'?
- The continuous movement of nutrients through an ecosystem
- These cycles include the carbon cycle and the nitrogen cycle
Give 3 physical characteristics of tropical rainforests
- High average temp
- Substantial rainfall
- Nutrient-poor soils
Name 5 causes of deforestation
1. Commercial farming
2. Logging
3. Road building
4. Mineral extraction
5. Population growth
Name 4 impacts of deforestation
1. Economic development
2. Soil erosion
3. Contribution to climate change
How does selective logging help the rainforest?
By preserving more of the forest's structure and allowing for faster recovery compared to clear-cutting. It involves only removing less valuable trees, leaving behind younger ecologically important trees.
How does ecotourism help the rainforest?
Creates a sustainable financial incentive for conservation. Ecotourists:
- Travel in small groups
- Keep to footpaths
- Don't leave litter
- Don't start fires
Name 4 development opportunities in hot desert environments
1. Mineral extraction
2. Energy from heat (thermal)
3. Farming
4. Tourism
Name 3 challenges that come with developing hot desert environments
1. Extreme tempertures
2. Limited water supply
3. Inaccessibility to deserts
Give 4 causes of desertification
1. Climate change
2. Overgrazing
3. Over-cultivation
4. Soil Erosion
Name 3 strategies used to reduce the risk of desertification
1. Water and soil management
2. Tree planting
3. Use of appropriate technologies
Give the names of both types of waves
Transverse and longitudinal
Define transverse waves, give components and 2 examples
- Definition: The water oscillates up and down as the wave travels horizontally
- Components: Crests and troughs
- Examples: Water waves, ripples on a pond
Define longitudinal waves, give components and examples
- Definition: The air vibrates back and forth as the wave travels in the same direction
- Components: Areas of low pressure and areas of high pressure
- Examples: Seismic waves
Explain mechanical weathering
- Rocks are broken down by forces like freeze-thaw cycles
Explain chemical weathering
Rocks are dissolved or changed by chemical reactions, often with rainwater or seawater
Explain the mass movement of sliding
Large blocks of material slide downhill, often due to gravity
Explain the mass movement of slumping
Saturated soil or rock slumps down a curved surface
Explain the mass movement of rockfalls
Pieces of rock detach from a cliff face and fall down, often due to weathering weakening the rock
Explain hydraulic action in erosion
The force of waves crashing against a cliff can compress air in cracks, weakening the rock and causing it to break
Explain abrasion in erosion
Waves carrying sediment grind down the cliff face
Explain attrition in erosion
Rocks and pebbles smash against each other in the water, becoming rounded and smaller
Explain what is meant by longshore drift
Waves approaching the shore at an angle move sediment along the coast in a zigzag pattern
Explain what is meant by deposition
- Sediment is deposited when the energy of waves decrease, allowing the material to settle. This often happens in areas like bays and estuaries
Give the characteristics of headlands and bays
- Headlands: high, rocky outcros of land that jut into the sea
- Bays: recessed coastal inlets, often with beaches, lying between headlands
Explain the formation of headlands and bays
- The sea erodes the softer rock lying perpendicular to the coast via processes like hydraulic action, abrasion and solution, forming bays
- The harder rock is more resistant and sticks out as headlands
- Over time, headlands become more exposed to erosion, while bays are more sheltered and often forming beaches
Give the characteristics of clifs and wave-cut platforms
- Cliffs: steep, often vertical rock faces along the coast
- Wave-cut platforms: a flat area of rock in front of a cliff, exposed at low tide
Explain the formation of cliffs and wave-cut platforms
1. Waves attack the base of a cliff through hydraulic action, abrasion and solution
2. This creates a wave-cut notch at the base of the cliff.
3. As the notch deepens, the cliff becomes unstable and eventually collapses.
4. The collapsed material is removed by the sea.
5. The cliff retreats inland, leaving behind a wave-cut platform.
6. This process continues, maintaining the steep profile of the cliff.
What do caves, arches, stacks and stumps from from?
Headlands made of resistant rock
Explain the formation of caves
- Form when waves erode cracks or weaknesses in the headland.
- Hydraulic action and abrasion enlarge the crack into a cave.
Explain the formation of arches
- If the cave is eroded all the way through the headland, it becomes an arch
- The arch has a roof of rock and an open space beneath.
Explain the formation of stacks
- The roof of the arch collapses due to gravity and continued erosion.
- This leaves an isolated pillar of rock called a stack
Explain the formation of stumps
- The stack continues to be eroded at its base and may eventually collapse.
- The remains are known as a stump, often visible at low tide.
Give characteristics of beaches
- Gently sloping landforms made of sand, pebbles, or shingle.
- Found between the high tide and low tide marks.
- Constructive waves build them up by depositing material.
- Can be sandy or shingle
Explain the formation of beaches
1. Created by deposition of sediment from the sea.
2. Waves lose energy as they approach the shore, especially in sheltered bays.
3. Constructive waves with a strong swash and weak backwash carry material up the beach and deposit it.
4. Longshore drift moves material along the coast, shaping beaches and forming beach profiles.
Give the characteristics of sand dunes
- Hills of sand formed at the back of a beach
- Have a layered structure: from embryo dunes to grey dunes
- Often found in coastal areas with wide beaches and plenty of dry sand.
Explain the formation of sand dunes
1. Dry sand is blown inland by the wind.
2. Sand accumulates around obstacles like driftwood or plants.
3. As more sand builds up, dunes form.
4. Marram grass helps stabilize dunes by trapping more sand with its roots and leaves.
5. Over time, dunes grow taller and move inland by succession
Give characteristics of spits
- Narrow strips of land made of sand or shingle.
- Project out into the sea from the coastline.
- Often curved at the end due to wave refraction or wind
Explain the formation of spits
1. Formed by longshore drift
2. When the coastline changes direction, the sediment is deposited.
3. Over time, this forms a spit.
4. If conditions remain calm, the spit extends further.
5. The end may curve due to wave action or prevailing wind direction.
Give characteristics of bars
- A bar is a ridge of sand or shingle that joins two headlands, blocking off a bay or lagoon.
- The water trapped behind the bar forms a lagoon.
Explain the formation of bars
1. A bar forms due to longshore drift
2. In cases where a bay has no strong river current, the spit can grow across it.
3. Eventually, it connects the two headlands, forming a bar.
4. Behind it, water is trapped and forms a lagoon
Give an example of a section of coastline in the UK
The Jurassic coast
Explain the fluvial processes relating to erosion
1. Hydraulic action: is the force of moving water hitting the riverbanks and bed. Water enters cracks in the riverbank or bed, compresses air, and weakens the rock over time. Common in upper course where the flow is faster
2. Abrasion: Eroded material carried by the river scrapes and grinds against the bed and banks. It deepens and widens the river channel
3. Attrition: Rocks and stones in the river collide with each other. They break into smaller, rounder, and smoother pieces. Reduces sediment size as material moves downstream.
4. Solution: River water dissolves soluble rocks like limestone and chalk. It's a chemical process, not physical
Explain the fluvial transportation processes
1. Traction: Large boulders and rocks are rolled along the riverbed. The river doesn’t have enough energy to lift them, so it pushes them along the bottom. Common in the upper course of the river where the bed is steep.
2. Saltation: Small pebbles or stones are bounced along the riverbed in a leapfrogging motion. The river has enough energy to lift particles briefly, but not keep them suspended
3. Suspension: Fine, light materials like silt and clay are carried within the water itself. These tiny particles are suspended and flow with the current. Common in the lower course, where there’s more water. Gives rivers their muddy appearance.
4. Solution: Minerals are dissolved in the water and carried in solution. Water dissolves soluble rocks like limestone. Occurs throughout the river but especially in areas with soluble bedrock.
What are interlocking spurs and how do they form?
Interlocking spurs are ridges of land that jut into a river valley. They form in the upper course as the river winds around resistant rock due to vertical erosion.
How is a waterfall formed?
1.A river flows over hard rock above soft rock.
2.The soft rock erodes quickly, forming a drop.
3. A plunge pool forms, undercutting the hard rock until it collapses.
4. This process repeats, and the waterfall retreats upstream.
What is a gorge and how is it formed?
A gorge is a steep-sided valley left behind as a waterfall retreats upstream through continued erosion and collapse of the overhanging rock
What are meanders and how do they form?
Meanders are bends in a river. They form when the river erodes the outer bank (forming a river cliff) and deposits on the inner bank (forming a slip-off slope), making the bend more pronounced over time.
What is an ox-bow lake and how is it formed?
An ox-bow lake is a U-shaped lake formed when a meander is cut off. The neck of the meander is breached during a flood, and deposition seals off the old loop.
What are levees and how do they form?
Levées are raised riverbanks formed when a river floods. Heavy sediment is deposited closest to the river, building up natural embankments over time.
What is a floodplain and how is it formed?
A floodplain is flat land beside a river. It forms through meander migration and sediment deposition during flooding, creating fertile land.
What is an estuary and how is it formed?
An estuary is the wide tidal mouth of a river where it meets the sea. It forms when river flow slows and deposits sediment, creating mudflats and salt marshes.