OCR B GCSE Geography Revision
Revision materials to support you in preparing for your GCSE Geography exams.
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What is a natural hazard?
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- AQA Paper 1 Revision
- The Challenge of Natural Hazards Revision
- What is a natural hazard?
- Types of Natural Hazards
- Hazard Risk
- Plate Tectonics
- Why do tectonic plates move?
- The global distribution of volcanoes and earthquakes
- Destructive plate margins
- Conservative plate margins
- Constructive plate margins
- Causes of earthquakes
- Measuring Earthquakes
- What are the effects of earthquakes?
- Responses to Earthquakes
- Case Study – HIC Earthquake
- Case Study – LIC Earthquake
- Why do people live in tectonically active areas?
- Managing Tectonic Hazards
- Global Atmospheric Circulation
- The Challenge of Natural Hazards Revision
What are the causes of drought?
A range of human and physical factors can lead to drought. These are summarised below.
- Physical Causes of Drought
- High pressure systems, often associated with stable and dry conditions, prevent the formation of clouds and precipitation, leading to prolonged dry periods.
- El Niño events disrupt normal weather patterns, often leading to reduced rainfall and drought conditions in various regions around the world.
- Rising global temperatures intensify evaporation rates, decrease soil moisture, and exacerbate drought conditions in already dry regions.
- Shifts in the ITCZ can alter rainfall distribution, causing some regions to experience prolonged dry periods while others receive more rainfall.
- Construction of dams can alter natural water flow, reducing downstream water availability and contributing to drought conditions in regions reliant on these water sources.
- Human Causes of Drought
- The removal of trees reduces the ability of the land to retain moisture, disrupts the water cycle, and leads to reduced rainfall and increased risk of drought.
- Over-exploitation of soil and water resources for high-yield crops can deplete water supplies and degrade soil, contributing to drought conditions.
- Over-irrigation depletes water reserves, lowers water tables, and can lead to soil salinization, reducing the availability of water for agriculture and other uses.
- Overgrazing by livestock removes vegetation cover, leading to soil erosion and reduced soil moisture retention, increasing susceptibility to drought.
- Construction of dams can alter natural water flow, reducing downstream water availability and contributing to drought conditions in regions reliant on these water sources.
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