Global Distribution of Tectonic Activity

This page examines the global pattern of plate margins and volcanic activity, which is essential for GCSE Geography Natural Hazards revision.

The world map shows the distribution of plate margins and active volcanoes. Key observations include:

1. There are more active volcanoes along destructive margins than constructive margins.
2. Many active volcanoes are found around the edge of the Pacific Ocean, forming the "Ring of Fire".
3. Active volcanoes also occur along the eastern side of North and South America.

Example: The Pacific "Ring of Fire" is a prime example of how plate tectonics influences the distribution of volcanic and seismic hazards.

At plate margin X (likely referring to a specific location on the map), the movement involves the oceanic plate subducting under the continental plate as they move towards each other.

Definition: Subduction zone - An area where two tectonic plates converge, with one plate sliding beneath the other.

Tropical Storms Formation and Tracking

This section focuses on the formation of tropical storms and tracking of hurricanes, which is a key component of The Challenge of Natural Hazards GCSE Geography.

Conditions leading to the formation of tropical revolving storms include:

1. Warm tropical seas with temperatures over 26.5°C
2. Occurrence during summer when seas are warmest
3. Formation at latitudes more than 5° north or south of the equator to allow for the Coriolis effect

Highlight: Understanding these conditions is crucial for predicting and preparing for tropical storms in vulnerable regions.

The map shows the track of Hurricane Irma in September 2017:

• The hurricane moved westward from Puerto Rico to Cuba
• It then turned northward, moving up to Georgia in the USA
• The wind speed of Hurricane Irma decreased from Category 5 to Category 1 between September 8 and 12, 2017

Example: Hurricane Irma's path demonstrates how these storms can affect multiple countries and change intensity over time.

Impacts of Tropical Storms and Climate Change

This page covers the effects of hurricanes and introduces the concept of climate change in the context of GCSE Geography Natural Hazards.

Primary effects of Hurricane Matthew in Haiti included:

1. Destruction of buildings
2. Flooding
3. Damage to infrastructure

Definition: Primary effects are the immediate impacts of a natural hazard, occurring during or immediately after the event.

Global climate change refers to long-term changes in rainfall patterns, temperature, and other climate indicators worldwide.

The diagram illustrates the process of global warming:

1. The sun's heat warms the Earth
2. Some heat is transferred back into the atmosphere
3. Greenhouse gases reduce heat loss to space
4. Additional greenhouse gases enhance this effect

Vocabulary: Greenhouse gases - Gases in the atmosphere that trap heat, contributing to global warming.

Sources of Greenhouse Gases and Atmospheric CO2 Levels

This section examines the sources of greenhouse gases and historical changes in atmospheric CO2 concentrations, which is crucial for understanding The Challenge of Natural Hazards in GCSE Geography.

Two sources of greenhouse gases suggested by the diagram are:

1. Vehicles
2. Factories

The graph shows changes in the amount of carbon dioxide (CO2) in the atmosphere over time:

• There was a steady CO2 concentration for about 100,000 years
• This was followed by a rapid rise in CO2 levels
• The amount of CO2 has increased by almost 100 parts per million (ppm) in the last 150 years

Highlight: The rapid increase in atmospheric CO2 over the past 150 years is a key indicator of human-induced climate change.

One reason for the change in CO2 concentration over time is the burning of fossil fuels in thermal power stations, which releases CO2 and other gases that build up in the atmosphere.

Example: The industrial revolution and subsequent increase in fossil fuel use correlates strongly with the rise in atmospheric CO2 levels.

Page 6: Carbon Dioxide Trends

The final page analyzes historical carbon dioxide concentration changes and their causes.

Example: CO₂ levels have increased by approximately 100 parts per million over 150 years.

Highlight: The graph shows a dramatic rise in atmospheric CO₂ concentrations since 1850, primarily due to human activities like fossil fuel combustion in thermal power stations.

Tectonic Hazards and Plate Boundaries

This section covers the basics of plate tectonics and different types of plate margins in GCSE Geography Natural Hazards.

A plate margin is where two tectonic plates meet. The diagram shows two different types of plate margins:

1. Destructive plate margins: Plates move towards each other, with the oceanic plate subducting under the continental plate. This can form composite volcanoes and deep ocean trenches.

2. Constructive plate margins: Plates move away from each other, allowing magma to rise and form new crust. This can create shield volcanoes and mid-ocean ridges.

Vocabulary: Subduction - The process where one tectonic plate moves under another and sinks into the mantle.

The oceanic crust has distinct characteristics compared to continental crust:

• It is lower in elevation
• Closer to the Earth's core
• Less dense than continental crust
• Relatively young (less than 200 million years old)
• Constantly renewed at constructive margins and destroyed at destructive margins

Highlight: Understanding the differences between plate margins and crust types is crucial for explaining tectonic hazard distribution and impacts in GCSE Geography.