Impacts of Earthquakes and Volcanic Eruptions

Question

Step-by-step solution

1. Step 1

   Definition (1 mark). A primary impact is a direct effect caused immediately by the earthquake itself — by the ground shaking, ground rupture or movement along the fault. It happens during, or in the first seconds of, the event.

2. Step 2

   Example (1 mark). Building collapse caused by the shaking is a primary impact (so are deaths and injuries crushed inside collapsing buildings, and roads/bridges fracturing). Pick a direct effect, not a knock-on one.

Question

Step-by-step solution

1. Step 1

   Identify (1 mark). A lahar (a mudflow of ash mixed with rain or melted snow/ice) is a secondary impact. Other valid answers: disruption to air travel from ash, famine where ash ruins crops, or homelessness.

2. Step 2

   Explain 'secondary' (1 mark). It is a knock-on effect — it is not caused directly by the lava/eruption itself but follows from it (the ash + later rainfall combine, in the hours or days afterwards). Secondary = indirect / delayed consequence.

Question

Step-by-step solution

1. Step 1

   Primary impacts (2 marks). Direct effects of the shaking and ground movement. They occur immediately, during the earthquake.

2. Step 2

   Primary examples (2 marks). Building collapse → people crushed (casualties). Ground rupture and surface faulting; roads, bridges and railways fractured.

3. Step 3

   Secondary impacts (2 marks). Knock-on (indirect) effects in the hours, days and weeks after the shaking stops.

4. Step 4

   Secondary examples (2 marks). Tsunamis (if the epicentre is undersea), fires from broken gas mains and electrical lines, disease from contaminated water, homelessness, business/economic collapse and displacement.

Question

Step-by-step solution

1. Step 1

   Negative — deaths (1 mark). Pyroclastic flows, ash inhalation, lahars (mudflows) and toxic gases kill people.

2. Step 2

   Negative — property destruction (1 mark). Lava and bombs destroy buildings; wet ash loads and collapses roofs.

3. Step 3

   Negative — air travel disruption (1 mark). Volcanic ash damages jet engines. Eyjafjallajökull (Iceland, 2010) grounded most European flights for about a week, costing airlines billions.

4. Step 4

   Positive — fertile soils (1 mark). Weathered volcanic ash creates exceptionally fertile soils. Around Mt Etna and Vesuvius these support productive vineyards and farming.

5. Step 5

   Positive — geothermal energy (1 mark). Volcanic heat drives geothermal power — Iceland generates around a quarter to a third of its electricity this way and heats most homes.

6. Step 6

   Positive — tourism (1 mark). Volcanoes attract tourists (Vesuvius/Pompeii, Yellowstone, Iceland), and the revenue supports local economies and jobs.

Question

Step-by-step solution

1. Step 1

   Building quality and codes (2 marks). Developed countries enforce strict building codes requiring earthquake-resistant design (deep foundations, cross-bracing, flexible frames). In poorer countries enforcement is weak and many homes are unreinforced concrete or mud-brick that pancakes — in Haiti 2010 a magnitude 7.0 collapsed huge numbers of buildings near Port-au-Prince.

2. Step 2

   Preparedness and warning (2 marks). Developed countries monitor faults, run early-warning systems and hold regular drills (e.g. Japan), so people react quickly. Developing countries often have little monitoring, fewer drills and a denser, less-educated exposed population.

3. Step 3

   Emergency response and wealth (2 marks). Richer countries have well-equipped search-and-rescue, hospital capacity and the wealth to act in the first hours (the 'golden' period). Poorer countries have limited resources, fewer hospitals and damaged roads, so rescue is slower and more people die of treatable injuries.

4. Step 4

   Long-term recovery (1 mark). Developed countries have insurance and government funds to rebuild quickly; developing countries depend on slow international aid, so disruption (disease, homelessness, lost livelihoods) lasts for years.

Question

Step-by-step solution

1. Step 1

   Plan the judgement. This is an evaluative extended response — you must argue BOTH sides and reach a supported conclusion. Decide your line: broadly agree for human impacts (deaths), but qualify it.

2. Step 2

   Case FOR the statement. Social/human impacts are usually worse in poorer countries: weak building codes and poverty meant Haiti 2010 (M7.0) killed ~220,000+ and left ~1.5 million homeless, with cholera later killing thousands more.

3. Step 3

   Counter-argument. Look at the type of impact. In ABSOLUTE economic cost, richer countries can lose more — Japan/Tōhoku 2011 (M9.0) cost an estimated US$220+ billion, the most expensive natural disaster ever, because there was so much high-value infrastructure to destroy. Same-magnitude comparison also matters: Chile 2010 (M8.8) was far stronger than Haiti but killed only a few hundred because of good building codes and wealth.

4. Step 4

   Reach a judgement (the key marks). Conclude with 'to what extent': impacts are greater in poorer countries for deaths, homelessness, disease and long-term recovery because vulnerability (building quality, preparedness, wealth) — not magnitude — drives human loss. But for absolute economic loss, impacts can be greater in richer countries. So I largely agree, but the answer depends on the type of impact measured.