IB Geography Option D

Geophysical Hazards — Interactive Flashcards

Hover over any flashcard to reveal the answer.

Earthquakes

Volcanoes

Mass Movements

Future Resilience

Earthquake Flashcards

Question

Why did Haiti 2010 produce far higher deaths than Christchurch 2011 despite similar magnitudes?

Answer

Haiti had weak building quality, almost no enforced building codes, fragile infrastructure, poor emergency response capacity, and high levels of poverty and informal housing.

Question

Haiti 2010 — key statistics?

Answer

Magnitude 7.0 Mw, ~220,000 deaths, 300,000+ injured, 1.5 million displaced, and economic losses of $8–14 billion.

Question

Christchurch 2011 — key statistics?

Answer

Magnitude 6.3 Mw, 185 deaths, ~2,000 injured, ~10,000 displaced, and rebuild costs of around $40 billion.

Question

What was the major secondary hazard in Christchurch?

Answer

Severe liquefaction across approximately 40 km² of eastern suburbs, producing over 46 million tonnes of silt.

Question

What is liquefaction?

Answer

Saturated loose sediments lose strength during shaking and behave like a liquid.

Question

Define focus and epicentre.

Answer

The focus is the underground rupture point, while the epicentre is the point directly above it on the Earth's surface.

Volcano Flashcards

Question

Mt Merapi 2010 — key statistics?

Answer

353 deaths, ~350,000 displaced, VEI 4 eruption, and economic losses of approximately $600 million.

Question

Why was Merapi highly dangerous?

Answer

Andesitic viscous magma generated explosive eruptions, pyroclastic flows reaching 700°C, and lahars moving through river valleys.

Question

Eyjafjallajökull 2010 — key statistics?

Answer

0 direct deaths, over 100,000 flights cancelled, 8 million passengers affected, and airline losses of ~$1.3 billion.

Question

Why did Eyjafjallajökull have global impacts despite low local deaths?

Answer

Fine ash particles entered European jet streams, causing six days of airspace closure across Europe.

Question

What is a pyroclastic flow?

Answer

A fast-moving, super-heated avalanche of gas, ash, and volcanic rock fragments.

Question

What is a lahar?

Answer

A volcanic mudflow made of water, ash, tephra, and debris moving down valleys like wet concrete.

Mass Movement Flashcards

Question

Oso Landslide 2014 — key statistics?

Answer

43 deaths, 49 homes destroyed, ~8 million m³ of debris, and ~1.5 km² buried.

Question

What triggered the Oso landslide?

Answer

Prolonged rainfall saturated loose glacial deposits, reducing internal friction and triggering slope failure.

Question

Vajont Dam 1963 — key statistics?

Answer

~2,000 deaths, 270 million m³ rockslide, and a 250 metre megatsunami wave.

Question

Why is Vajont considered partly human-induced?

Answer

Reservoir water lubricated a pre-existing failure plane, while engineers ignored warning signs of accelerating slope movement.

Question

Define mass movement.

Answer

The downslope movement of rock or soil under gravity.

Future Resilience Flashcards

Question

What are base isolators?

Answer

Rubber-and-steel bearings placed beneath buildings to absorb earthquake movement and reduce shaking transfer.

Question

What is land-use zoning?

Answer

Restricting development in high-risk hazard zones such as unstable slopes, tsunami zones, or fault areas.

Question

What technologies improve volcano prediction?

Answer

GPS receivers, seismometers, tiltmeters, and 3D seismic tomography monitoring magma chamber activity.

Question

What are the 3 stages of post-event management?

Answer

Rescue, rehabilitation, and reconstruction.

Question

Why is governance critical in disaster management?

Answer

Strong governance improves building standards, emergency response coordination, preparedness, and long-term reconstruction.