Geography- tectonics

What’s a hazard?

Whittow- The potential threat to life that a tectonic event has

What’s a disaster?

Degg- The realisation of hazards that have killed 10+ people and have affected 100+ peopl

What’s the DEGG MODEL?

How vulnerability and hazard interact to make a disaster (2 overlapping circles, change size)

What’s the equation to measure risk?

The disaster risk equation: Risk = (Hazard x Vulnerability) / capacity

What affects risk?

Unpredictibility, lack of alternatives, dynamic hazard, cost benefit, russian roulette reaction

Why is resilience important in a disaster?

It controls the ability the population has to “spring back” from a disaster.

Why are older popualtions more vulnerable?

Limited mobility

Layers of the earth

Liphosphere- crust (100km thick) and solid uppermost mantle

Astenosphere

Mesophere

Outer core

Inner Core

What’s a seismic hazard?

When the rocks in the earth are within 700km of the earth’s surface go under high amounts of pressure so they then break and become displaced.

The 3 types of a fault? Where do these happen?

Normal fault- tension causes an extentional fault with an angle of 60 degees so ricks thin. This happens on a divergent plate boundary (constructive)

Thrust/ reverse- Compression forces cause folding or breaking. Happens at a collision/ destructive plate boundary

Strike-slip- Stress and shoring forces slide past eachother at a conservative plate boundary.

3 types of seismic wave?

P- Compression: these are the fastest and travel through slid and liquids.

S- Secondary waves, these are slower transverse waves which can only travel through solids

L- land waves: travel through surface

(also body waves travel through earth’s body

Why do destructie plate margins create earthquakes? (process of this) also how do strato-volcanoes form?

1. plates move towards eachother (convergent)

2. Older and colder and denser ocean lithosphere subducts

3. Subducting slab will become locked so pressure builds up and then released as an earthquake in the Beriaff zone

4. wet partially melting coccurs at the ocean crust which creates intermediate magma

5. The magma rises to surface and form strato-volcanoes