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S5 Geography | Natural Hazards Paper 3 (Challenge)
S5 Geography | Natural Hazards Paper 3 (Challenge)
Paper 3 is multi-step: logarithmic energy, deep and near-shore tsunami speed, ocean crossing time, cyclone rainfall volume, ash clearance, landslide mass, channel overloading and disaster losses.
Attempt first, mark afterwards Allow about thirty-five minutes; every item needs at least two steps, converting a physical quantity into time, truckloads or money, then sanity-checking the order of magnitude.
01 Paper details (check answers afterwards)
| Item | Detail |
|---|---|
| Questions | 10 items |
| Suggested time | About 35 minutes |
| Difficulty mix | Foundation 2 · Intermediate 2 · Challenge 5 · Error redo 1 |
| Chapter | Chapter: S5 Geography | Natural Hazards |
| Level | S5 (Secondary 5) Geography |
02 Questions (10 items)
- FoundationHow many times more energy is released going from magnitude 5 to 6.5?
- FoundationA tsunami crosses water 5,000 m deep at about the square root of 9.8 times depth. What is its speed in m/s and km/h?
- IntermediateUsing that speed, how many hours does the tsunami take to reach a coast 3,000 km away?
- IntermediateNear shore in 20 m of water the same tsunami slows to about 14 m/s. How many minutes do people within 3,000 m of the shore have?
- ChallengeA cyclone covers a radius of about 300 km with mean rainfall of 250 mm. What is the total volume of rain?
- ChallengeAfter an eruption 200 square kilometres are covered by 5 cm of ash. What volume is that, and how many days to clear it with 20 cubic metre trucks making 500 trips a day?
- ChallengeA landslide removes a block 40 m long, 60 m wide and 3 m thick, with a density of 1.8 tonnes per cubic metre. What are its volume and mass?
- ChallengeA drainage channel is designed for 150 m³/s at a 20 year return period. Climate change raises the same-frequency peak by 25 per cent. What is the new flow and the overloading?
- ChallengeBuildings worth 4.8 billion dollars suffer average quake damage of 35 per cent, and insurance covers only 40 per cent of the loss. What are the total loss and the payout?
- Error redoA student writes that each magnitude unit means ten times more energy. What is wrong, and what are the true energy and amplitude ratios?
03 Answers and one-line notes
| # | Answer | One-line note |
|---|---|---|
| 1 | About 177.83 times. | Ten to the power 1.5 times 1.5 is 177.83, so fractional magnitude gaps can be handled in one step. |
| 2 | About 221.36 m/s, or 796.89 km/h. | The square root of 9.8 times 5,000 is 221.36 m/s, which is 796.89 km/h; deeper water means faster travel. |
| 3 | About 3.76 hours. | 3,000,000 m divided by 221.36 m/s is 13,553 s, or 3.76 hours, which is the whole warning window. |
| 4 | About 3.57 minutes. | 3,000 divided by 14 is 214 s, about 3.57 minutes; slowing lets the wave height grow, which is why the last stretch is the most destructive. |
| 5 | About 70,685,834,705.77 cubic metres, roughly 707 hundred million cubic metres. | The area is pi times 300 squared, about 282,743 square kilometres, and multiplying by 0.25 m gives 70,685,834,705.77 cubic metres, a figure that depends on assuming a uniform mean. |
| 6 | 10,000,000 cubic metres, or 500,000 truckloads, taking 1,000 days. | 5 cm is 0.05 m and 200 square kilometres is 200,000,000 square metres, giving 10,000,000 cubic metres, which is 500,000 loads at 500 a day for 1,000 days. |
| 7 | 7,200 cubic metres and 12,960 tonnes. | 40 times 60 times 3 is 7,200 cubic metres, and multiplying by 1.8 gives 12,960 tonnes; volume is not mass. |
| 8 | 187.5 m³/s, an excess of 37.5 m³/s. | 150 times 1.25 is 187.5 m³/s, which is 37.5 m³/s above design, so the channel now overtops more often than every twenty years. |
| 9 | A loss of 0.17 billion and a payout of 0.07 billion dollars. | Thirty-five per cent of 4.8 billion is 0.17 billion, of which insurance pays 0.07 billion, leaving the rest to government and owners. |
| 10 | Energy rises about 31.62 times per unit while amplitude rises about ten times. | Magnitude is logarithmic in amplitude, so each unit is ten times the amplitude and ten to the power 1.5, about 31.62, in energy; calling that tenfold underestimates energy threefold and under-designs defences. |
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.