Future resilience and adaptation practice questions.

Hazard management strategies are often grouped as modifying the event, modifying vulnerability, or modifying the loss. Which strategy modifies the loss?

• Enforcing a seismic design standard for new schools and hospitals
• Zoning the valley floor below a volcano as open space only
• Paying householders from a national earthquake insurance fund
• Running annual evacuation drills in coastal tsunami zones

Answer: Paying householders from a national earthquake insurance fund

Insurance changes neither the shaking nor the building, only who carries the cost afterwards; codes, zoning and drills all act before the event by cutting vulnerability or exposure.

Japan's earthquake early warning system can alert Tokyo a few tens of seconds before strong shaking from an offshore rupture arrives. Which physical fact makes this possible?

• Satellites detect crustal strain building up hours before rupture
• Deep-focus earthquakes release their energy more slowly than shallow ones
• Surface waves travel faster than body waves through the crust
• P waves arrive before the more destructive S and surface waves

Answer: P waves arrive before the more destructive S and surface waves

Sensors near the epicentre register the fast, weak P wave and transmit the alert electronically, so the warning overtakes the slower S and surface waves that do the damage.

After the 2010 Haiti earthquake, volunteers around the world traced satellite imagery to map streets, camps and blocked roads within days. What was the main value of this crowdsourced mapping to relief agencies?

• It measured the magnitude of aftershocks more precisely than seismometers
• It gave responders a usable base map where none had existed before
• It showed where the next aftershock would bring buildings down
• It removed the need for damage assessment teams on the ground

Answer: It gave responders a usable base map where none had existed before

Relief logistics need geography first: without a street-level base map, agencies cannot route supplies or locate camps, which is why volunteer mapping is now a standard part of the response phase.

Japan's earthquake early warning system detects the fast, weakly damaging P-wave and issues an alert before the slower S-wave arrives. What does this buy?

• Seconds to tens of seconds to stop trains, halt surgery and take cover
• Several days of notice, allowing full evacuation of a city
• A reliable prediction of the date of the next major earthquake
• A reduction in the magnitude of the earthquake itself

Answer: Seconds to tens of seconds to stop trains, halt surgery and take cover

The system exploits the difference in wave speed, not any ability to forecast, so the warning is short and arrives only after rupture has begun. Those seconds are still enough for automatic actions - braking trains, closing valves, opening lift doors - which is where most of the benefit lies.

After its 2010 earthquake, Chile recorded far fewer deaths than several comparable events elsewhere. Which factor is most often credited?

• Long-established, enforced seismic building codes
• A much smaller magnitude than reported at the time
• The complete absence of coastal settlement in the country
• An accurate prediction of the date issued weeks beforehand

Answer: Long-established, enforced seismic building codes

Chile had decades of seismic design requirements and, critically, the inspection and liability regime to make them stick. Enforcement is the part that transfers least well between countries, which is why codes on paper are a weak predictor of outcomes.

The Sendai Framework for Disaster Risk Reduction shifted international emphasis from managing disasters to managing risk. What does that change in practice?

• More investment before events, in prevention and resilience, not only in response
• The abolition of emergency relief operations after events
• A requirement that all hazardous areas be permanently evacuated
• A transfer of all responsibility from governments to insurers

Answer: More investment before events, in prevention and resilience, not only in response

Managing risk means reducing exposure and vulnerability in advance - land-use planning, retrofitting, early warning, resilient infrastructure - rather than funding the response afterwards. The obstacle is political: prevention spends money now against a loss that may fall on a later administration.