Plate Tectonics
Explain one piece of evidence that continents were once connected.
Fossil correlation – identical fossils (e.g., Mesosaurus) found in South America & Africa suggest these continents were once joined. This cannot occur if oceans always separated them.
Why do some earthquakes cause tsunamis while others do not?
Only quakes that cause vertical displacement of the seabed can displace water. Strike-slip faults do not lift or drop the seabed, so they do not trigger tsunamis.
How did colonialism change Africa’s borders?
Borders were drawn by European powers with no regard for ethnic groups → causing conflict and political instability that persists today.
Why does East Africa have so many volcanoes?
The region lies on a constructive boundary and several rifting zones → magma rises through thinned crust.
What does “quality of life” mean?
The standard of health, comfort, and happiness of individuals
Why are earthquakes, volcanoes and mountain belts often found together?
These features form where plates interact. Convergent boundaries create mountain belts & explosive volcanoes; slipping plates generate earthquakes. They cluster where plates collide or slide past.
Why is earthquake risk higher in LEDCs, even if the magnitude is the same?
Weak construction, limited emergency services, high population density in informal settlements, slow response systems → increase casualties.
How did colonialism shape Africa’s economic structure?
Economies were built around extracting raw materials for Europe → little industrial development → dependency on exporting low-value goods.
Why are river basins crucial for African agriculture?
They provide reliable water, alluvial soils, hydroelectric potential, and support large populations in otherwise dry regions.
Name one challenge for African cities.
Rapid urbanisation leading to housing shortages.
How does mantle convection actually move tectonic plates?
Heat from Earth’s core warms mantle material → it rises, cools, sinks → creating a circular motion. Plates sitting on top are dragged, pushed, or pulled, driving collision or separation.
Why are composite volcanoes more dangerous than shield volcanoes?
Composite cones have viscous silica-rich magma, trapping gases → violent eruptions, pyroclastic flows, lahars, ash clouds → more deadly.
Explain how Africa’s colonial past affects modern education and healthcare systems.
Underinvestment by colonial rulers led to weak institutions. Many nations started independence with limited infrastructure → long-term developmental challenges.
Why is North Africa extremely dry?
It lies under the subtropical high-pressure belt, causing sinking air and minimal rainfall → Sahara Desert.
Name one opportunity for sustainable growth.
Renewable energy, tourism, education investment.
Why do divergent boundaries still produce earthquakes even though plates move apart?
As plates separate, new crust forms. This creates tension and fractures → shallow earthquakes. Though less destructive, they still release energy as the crust cracks.
Why do many people live near volcanoes despite the risks?
Very fertile soils, cheap land, geothermal energy, hot springs, tourism income. Economic benefits often outweigh perceived danger.
Why do some people argue that modern investment (e.g., China) resembles “new imperialism”?
Foreign investors extract resources or build infrastructure using their own labour → profits leave Africa; limited long-term capacity building.
Can the Sahel survive long-term climate change? Evaluate.
Possible via drought-resistant crops, reforestation (Great Green Wall), sustainable grazing. However, extreme heat, conflict, and poverty challenge long-term recovery.
How can Africa avoid dependency on other countries?
Invest in local skills, diversify economies.
Compare ridge push and slab pull as forces that move plates.
Ridge push: New magma at mid-ocean ridges forms high ground → gravity pushes plates sideways. Slab pull: At subduction zones, dense oceanic crust sinks and drags the rest of the plate. Slab pull is considered the dominant force.
Evaluate the statement: “Volcanoes are easier to predict than earthquakes.”
True: Volcanoes show clear warning signs (gas, tremors, swelling). False: Exact eruption timing & explosivity cannot be perfectly predicted.
Evaluate the statement: “Africa’s future cannot be understood without understanding its past.”
Colonialism shaped borders, economies, land rights, languages, trade patterns. Present challenges and opportunities are rooted in historical context → essential for analysis.
Explain how Africa’s climate is influenced by both latitude and altitude.
Latitude affects solar energy (equator hottest, poles cooler). Altitude cools temperatures (e.g., Mount Kilimanjaro snow despite being near equator).
Discuss: “Africa is a continent of both challenges and opportunities.”
Yes—while poverty and inequality exist, economic and social improvements are increasing.