Earthquakes, floods and disaster response
How earthquakes and floods affect people, and how we manage disasters. Read one part at a time and tap “I know this”. Then test yourself in the quiz.
Know it already? Jump straight to the quiz
Earthquakes and people
- The Richter scale measures an earthquake’s magnitude (strength). Each step up means the ground shakes about 10 times more: a magnitude 6 quake shakes about 10 times more than a 5.
- Aftershocks are smaller quakes after the main one; people sleep outside for fear that damaged buildings may collapse.
- In poorer countries more people die, because buildings are weaker and help is slower.
- South Africa lies far from plate boundaries, but Tulbagh was struck by a strong quake in 1969.
- Effects of earthquakes: injuries and deaths when buildings collapse; disease when water pipes and sewers break; people are displaced (they lose their homes); roads, bridges, power lines and pipes are damaged; fires from broken gas pipes and electric wires; and tsunamis when the quake is under the sea.
Stay away from windows and tall shelves: glass can shatter and heavy things can fall. If the sea suddenly pulls back after a quake, go to high ground at once: a tsunami is coming.
Floods
A flood happens when more water arrives than can drain away. When we pave over ground and wetlands, water runs off faster and floods get worse. Wetlands soak up water like a sponge and release it slowly. It is dangerous to build on a river’s flood plain.
- Causes of floods: unusually heavy rain in a short time; plants removed by farming, fires or building, so rain runs off instead of soaking in; paving over ground and draining wetlands; and tsunamis.
- Effects: injuries and deaths, diseases such as cholera from dirty water, people displaced, topsoil washed away (soil erosion), crops and fields destroyed, and damage to homes, roads and bridges.
Disaster management
A natural hazard becomes a disaster when it seriously harms people. Disaster management means planning ahead: early warnings, not building on flood plains, and a plan for after the disaster.
- After an earthquake clean water comes first: broken pipes and sewers make water unsafe.
- People forced to leave their homes because of a disaster are displaced people.
Who is most at risk, and how do we prepare?
| Higher risk | Why |
|---|---|
| People living near plate boundaries | Earthquakes and volcanoes happen most there |
| Homes on a floodplain or riverbank | The water reaches them first |
| Poorly built houses | They collapse or wash away more easily |
| Poor communities | Less money for strong buildings, insurance and repairs |
- Before the disaster: early warning systems, strong buildings, no building on floodplains, emergency drills and an emergency bag with water, food and a torch.
- During and after the disaster: evacuate to higher or safe ground, rescue teams, shelter, clean water and medical help, and then rebuilding.
Case studies
| Earthquake | Türkiye and Syria, 6 February 2023 |
|---|---|
| Cause | A magnitude 7,8 earthquake along the East Anatolian Fault, where two plates slide past each other |
| Effects | More than 50 000 people died, many when badly built blocks of flats collapsed. Millions lost their homes in the cold winter. |
| Response | Rescue teams from many countries, including South Africa, freed people from the rubble; tents, food and medical help were sent. |
| Flood | KwaZulu-Natal, April 2022 |
|---|---|
| Cause | Days of extremely heavy rain caused floods and landslides around Durban (eThekwini) |
| Effects | More than 400 people died and over 13 000 households were affected. Thousands of homes were destroyed, worst of all informal homes on riverbanks and steep slopes. Roads, bridges, water pipes, schools and the port were damaged. |
| Response | The government declared a national state of disaster; rescue teams and the army rescued people, and shelter, food and clean water were handed out. |
Remember this and test yourself
- The Richter scale measures strength: a magnitude 6 quake shakes about 10 times more strongly than a 5.
- Aftershocks follow the main quake. In 1969 Tulbagh was struck by a strong earthquake.
- Poorer countries suffer more: buildings are weaker and help is slower. South Africa lies far from plate boundaries.
- A flood happens when more water arrives than can drain away; wetlands soak up water, and paved ground makes floods worse.
- A hazard becomes a disaster when it seriously harms people; disaster management plans ahead.
Write these points in your book. Read them again the night before the test.
In an earthquake: drop, cover, hold on. In a tsunami: high ground, now.
Important words
First say what the word means, then turn the card over.
Match column A to column B
Tap a word in column A, then its meaning in column B. You can also start in column B.
True or false?
Read the question and the answer. Is the answer right? Tap True or False.
Now the real quiz!
The quiz has many more questions on this topic. Every question shows straight away whether you are right and explains why.
Take the quiz: Earthquakes, floods and disaster response- Read one part together and ask your child to tell it back in their own words.
- The ticks (“I know this”) are saved on this device only. We never ask for names or emails.
Follows CAPS for Grade 7 Social Sciences (Geography). Always check your teacher’s notes and textbook too.