Science Ideas and Concepts
Scientific study requires a basic knowledge and understanding of ideas and concepts. This collection explains the ideas that are fundamental to Earthquakes.
Faults – Information Sheet
A fault is a fracture in the Earth’s crust where the rock mass on either side has been displaced. Earthquakes occur on active fault lines.
Inside the Earth – Information Sheet
We believe the Earth is divided into layers comprised of the crust, upper mantle, mantle and outer and inner core. This model explains the Earth’s tectonic plate movements and other phenomena, such as our magnetic field. But how did we arrive at this model?
Moulding the Earth – Information Sheet
When strain builds up in the Earth as a result of stress from tectonic movement, materials like clay can change shape rather than fracture. This change is not reversible when the stress is removed – it is referred to as plastic rather than elastic. If the stress on the material continues past a certain point, it will pass beyond the range of plasticity and fracture.
Plate tectonics – Information Sheet
The plate tectonics theory explains that the Earth’s outer layer is divided into oceanic and continental plates that slide over the layer below – this movement is responsible for geologic activity such as earthquakes.
Seismic waves – Information Sheet
Seismic waves are waves that travel through or over the Earth. They are usually generated by movements of the Earth’s tectonic plates (earthquakes) but may also be caused by explosions, volcanoes and landslides. Studies of the different types of seismic waves can tell us much about the nature of the Earth’s structure.