South Africa is a seismically active country, with a large amount of seismic activity occurring along its coastal regions. Earthquakes are caused by the movement of tectonic plates underneath the Earth’s surface, which can cause stress and pressure on rock formations in other parts of the world. When this happens, it causes earthquakes that occur at varying magnitudes depending on their size and location.
Earthquakes
It is estimated that there are around 14 earthquakes per day, with a magnitude of 3 or higher. Most of these earthquakes occur in the Pacific Ring of Fire, which extends around the Pacific Ocean and includes major areas such as Japan and New Zealand.
When an earthquake occurs, the movement of tectonic plates causes it beneath the Earth’s surface. The California Institute of Technology estimates that there are over 100 active faults in South Africa alone. This means that there is always potential for an earthquake to occur here.
Ground Shaking Damage
An earthquake can cause damage to buildings and infrastructure. It can also affect roads and bridges, dams and reservoirs, pipelines, power lines.
Landslides and Rockfalls
Landslides and rockfalls are the most common type of landslide, accounting for around three-quarters of all landslides that occur in South Africa. They can be triggered by earthquakes, but also by severe weather such as heavy rain or heatwaves.
Landslides and rockfalls can cause damage to buildings and infrastructure, including roads and bridges. They may also lead to loss of life if people are buried under falling debris or suffer fatal injuries from being hit by flying rocks or rubble.
Damaged Buildings and Infrastructure
Damage to Buildings and Infrastructure
A major earthquake can have devastating effects on buildings and infrastructure, including:
- Loss of life due to the collapse of structures.
- Collapsed or damaged roads, bridges, railways, and runways.
- Damaged utility lines such as gas or water supply systems.
Disruption of Services and Loss of Life
The effects of earthquakes are widespread and varied and can range from the loss of life to disruption of services, damaged buildings and infrastructure. The extent of damage depends on factors such as the size, location and depth of a quake.
In South Africa there are many large cities in the main populated areas which are vulnerable to earthquakes: Cape Town, Johannesburg, Pretoria, Durban and Bloemfontein (to name a few). In these areas it is estimated that there is potential for casualties exceeding thousands if a major earthquake occurs.
