Topic 2: Plate Tectonics
Key Question 1: Why are some areas more prone to tectonic hazards?
What is a natural hazard?
· Definition of natural hazards and the main ways they may be classified
– climate-related hazards
o floods
o storms
– tectonic hazards
o earthquakes
o volcanic eruptions
What is the internal structure of the Earth?
What is a tectonic plate?
· Internal structure of the Earth
– Layered structure
o Core
o Mantle
o Continental crust and oceanic crust
– Characteristics of each layer
o Thickness
o Solid or liquid state
Why do plates move?
Movement of tectonic plates driven by the pull of subducting plates and convection currents circulating within the mantle
What are the different types of plate movement?
· Names, types and locations of major plates and plate boundaries in the world
– North American Plate
– South American Plate
– Eurasian Plate
– Indian Plate
– African Plate
– Nazca Plate
– Pacific Plate
– Philippine Plate
– Australian Plate
· Types of plate boundaries and examples:
– Divergent: oceanic-oceanic (e.g. Mid-Atlantic Ridge), continental-continental (e.g. Great Rift Valley of East Africa)
– Convergent: oceanic-oceanic (e.g. Mariana Trench), continental-continental (e.g. Himalayas), oceanic-continental (e.g. Andes)
– Transform (e.g. San Andreas Fault)
Key Question 2: What landforms and associated tectonic phenomena are found at plate boundaries?
Why are some landforms found at different plate boundaries and how are they formed?
· Plate movements and associated landforms
– Divergent: Rift valleys and block mountains
– Convergent: Fold mountains
– Divergent and Convergent: Volcanoes
What phenomena are found at different plate boundaries and how are they formed?
· Phenomena and their causes
– Earthquakes
– Tsunamis
– Volcanic eruptions
· Structure of volcanoes
– Crater
– Caldera
– Vent
– Magma chamber
· Characteristics and formation of volcanoes
– Shield volcano (e.g. Erta Ale in Ethiopia)
– Stratovolcano (e.g. Puy de Domes in France and Mt Pinatubo in Philippines)
– Viscosity of lava
o high-silica vs low-silica
What are the possible benefits and risks of living near volcanic areas?
· Benefits of living in volcanic areas
– Fertile soil
– Precious stones and minerals
– Tourism
– Geothermal energy
· Risks of living in volcanic areas
– Massive destruction by volcanic materials
– Pollution
What are the hazards associated with earthquake zones?
· Risks associated with living in earthquake zones
– Disruption of services
– Landslides
– Destruction of properties and infrastructure
– Loss of lives
– Tsunamis
Key Question 3: How do people prepare for and respond to earthquakes?
How do people respond to natural hazards like earthquakes?
· People may respond to natural hazards in several ways:
– Preparedness measures
o Land use regulation
o Infrastructure
o Emergency drills
o Earthquake and tsunami monitoring and warning systems
– Short-term responses
o Search and rescue
o Emergency food and medical supplies
– Long-term responses
o Rebuilding of infrastructure
o Provision of health care
With reference to a case study of an earthquake that has taken place, consider the following guiding questions:
1) What are the effects of the earthquake on people and the environment?
2) How do people respond to the natural hazard?
3) What can be done to reduce the risks associated with earthquakes?
4) Is it a risk or an opportunity for people to live in the earthquake-prone area?