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S5 Geography | Natural Hazards Paper 4 (Error Retry)
S5 Geography | Natural Hazards Paper 4 (Error Retry)
Paper 4 targets the most common mistakes: unit conversion, rainfall volume, density to tonnage, factors of safety, magnitude and energy, return periods, wind pressure, tsunami speed, rounding truckloads and runoff coefficients.
Redo what went wrong Allow about thirty minutes; write the unit before substituting, and when marking decide whether the error was in conversion, formula or concept.
01 Paper details (check answers afterwards)
| Item | Detail |
|---|---|
| Questions | 10 items |
| Suggested time | About 30 minutes |
| Difficulty mix | Foundation 4 · Intermediate 3 · Challenge 2 · Error redo 1 |
| Chapter | Chapter: S5 Geography | Natural Hazards |
| Level | S5 (Secondary 5) Geography |
02 Questions (10 items)
- FoundationA vehicle travels at 72 km/h. Convert this to metres per second.
- FoundationA storm delivers 80 mm of rain over a 25 km² catchment. If all of it stays on the ground, what is the total volume in cubic metres?
- FoundationA landslide deposits 4,500 m³ of debris with a density of 1.9 tonnes per m³. What is the total mass in tonnes?
- FoundationA slope has a soil shear strength of 48 kPa and a driving shear stress of 32 kPa. What is the factor of safety, and does it meet the 1.4 requirement?
- IntermediateAn earthquake increases from magnitude 5.5 to 6.5. By what factor does the energy increase, and by what factor does ground amplitude increase?
- IntermediateA storm has a return period of 20 years. What is the chance of at least one such storm in the next 10 years?
- IntermediateWind speed rises from 120 km/h to 240 km/h. By what factor does the dynamic pressure on a building increase?
- ChallengeA tsunami crosses ocean that is 1,000 m deep. What is its speed in m/s and km/h, and how long does it take to cross 500 km?
- ChallengeA landslide body is 45 m long, 30 m wide and 2.5 m thick. What is its volume in m³, and how many 18-tonne truckloads are needed at 1.9 tonnes per m³?
- Error redoA 12 km² catchment receives 60 mm/h of rain for 3 hours with a runoff coefficient of 0.75. What is the total runoff volume in m³?
03 Answers and one-line notes
| # | Answer | One-line note |
|---|---|---|
| 1 | 20 m/s (72 × 1000 / 3600). | To convert km/h to m/s, divide by 3.6; never read 72 km/h as 72 m/s. |
| 2 | 2,000,000 m³ (0.080 m × 25,000,000 m²). | Convert millimetres to metres by dividing by 1000, and square kilometres to square metres by multiplying by 1,000,000. |
| 3 | 8,550 tonnes (4,500 × 1.9). | Mass in tonnes equals volume times density; 4,500 is a volume, not a mass. |
| 4 | 1.5, which meets the requirement (48 / 32). | The factor of safety is shear strength divided by driving stress; below 1 the slope fails. |
| 5 | Energy about 31.6 times; amplitude about 10 times. | Energy scales with amplitude to the power 1.5, so one magnitude unit is far more than ten times the energy. |
| 6 | About 40.1% (1 – 0.95^10). | A return period is an annual probability of 1 in 20, not a fixed 20-year gap; ten years still gives about a 40% chance. |
| 7 | 4 times. | Dynamic pressure is proportional to the square of wind speed, so doubling speed quadruples the load. |
| 8 | About 99.0 m/s (356.6 km/h); about 84 minutes for 500 km. | Speed is the square root of 9.81 times the depth, so deeper water gives faster waves, close to airliner speed in the open ocean. |
| 9 | 3,375 m³; 6,412.5 tonnes, so at least 357 truckloads. | Truckloads must be rounded up; 356.25 loads cannot carry the full mass. |
| 10 | 1,620,000 m³ (0.060 × 3 = 0.18 m; 0.18 × 12,000,000 × 0.75). | The usual errors are dropping the runoff coefficient or reading 60 mm as 60 m, a thousandfold mistake. |
04 What to do after marking
- After marking, redo only the wrong items and write down which step went wrong (formula, unit, or misread number).
- Repeat the same item two days later; move to the next paper only when both attempts are correct.
- Parents only need the answer and note columns; there is no need to explain every item.
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Questions and answers are written originally by the TutorZone team and are not taken from any school, publisher or examination authority paper. Every value is checked by computer.