Paper 1 - Hazards Flashcards
Definition - Aseismic buildings
Buildings designed to withstand or minimise destruction during an earthquake
Definition - Asthenosphere
The upper mantle layer of the Earth. It is semi molten and approximately 2000km wide
Definition - Ash
Fine particles and dust ejected during an eruption, which can remain airborne as clouds accumulate on the ground
Definition - Continental Crust
Crust that forms the continents of the lithosphere, on average 35km thick
Definition - Continental drift
The movement of tectonic plates, due to varying weights of crust. It was originally thought that convection currents caused the movement of the plates, but now slab pull is thought of as the primary driving force
Definition - Convection currents
The circulation of magma within the mantle. Magma is heated by radioactive processes in the core and cools at the surface, and so circulates between the 2 places
Definition - Degg’s model
This model shows that a hazard becomes a disaster if it affects a vulnerable population
Definition - Epicentre
The point on the surface, directly above the earthquake’s origin
Definition - Fatalism
The belief that hazards are uncontrollable, so any losses should be accepted and mitigation is unnecessary
Definition - Focus
The place in the crust where the pressure / seismic activity is released
Definition - Hazard Management Cycle
The sequence of governance of a natural hazard - preparedness, response, recovery and mitigation
Definition - Hot spot
Volcanoes found away from the plate boundary, due to a magma plume closer to the surface
Definition - Jokulhlaup
A sudden glacial flood caused by a glacier on top of or near a volcano melting due to the heat from the eruption
Definition - Lahar
A flow of mud and debris
Definition - Lithosphere
The upper crust of the Earth - average thickness is 100km
Definition - Love waves
A surface earthquake wave with horizontal displacement
Definition - Mid ocean ridge
Parting oceanic plates at a constructive plate boundary creates a ridge, with new land at the base of the oceanic valley
Definition - Moment Magnitude Scale
A measure of an earthquake’s energy released, considered the most accurate measure
Definition - Oceanic crust
Crust, usually thinner than continental crust, that forms the sea floor. It is on average 7km thick
Definition - Paleomagnitism
The alternating polarisation of new land created. As magma cools, the magnetic elements within will align with the earth’s magnetic field, which can alternate over thousands of years
Definition - Park’s model
A model describing the decline and recovery of a country over time, following a natural disaster
Definition - Partial melting
Elements within the lithosphere have different melting points, and so rock is partially melted, partially solid
Definition - Primary waves
An earthquake wave causing compressions within the body of rock
Definition - Pyroclastic flow
A mixture of gases and rock fragments, at high temperatures travelling at rapid speeds
Definition - Richter scale
A logarithmic measure of an earthquake’s intensity
Definition - Secondary waves
An earthquake wave causing vertical displacement within the body of rock
Definition - Seismic waves
The energy released during an earthquake, in the form of primary, secondary, love and Rayleigh waves
Definition - Rayleigh waves
An earthquake wave causing compressions within the body of rock
Definition - Slab pull
The force contributing to the movement of tectonic plates. Slab pull is due to the weight of the plate
Definition - Subduction
Oceanic plate is forced below continental plate, due to the oceanic plate being more dense than the continental plate
Definition - Tsunami
Initial vertical water displacement creates waves, with large destructive power
Definition - Volcanic Explosivity Index
A measure of the magnitude of a volcano’s eruptions
Definition - Volcanic Island Arc
A series of volcanoes that are formed consecutively, as a tectonic plate moves across a magma plume
Example of a key Tsunami case study
Japan 2011 Tsunami
- 15,000 deaths
- 1 million buildings damaged with 300,000 destroyed
- $250 billion in damages
Example of a key volcanic case study
Eyjafjallajokul, Iceland - 2010
- 0 deaths
- Local population evacuated
Example of a key earthquake case study
Port au Prince, Haiti - 2010
- 3,500,000 people affected
- 220,000 deaths
- 300,000+ injured
- 200,000 houses damaged - 100,000 destroyed
- 1,500,000 people became homeless
- $8 billion in damages
Definition - Liquefaction
When soil is saturated, the vibration of a earthquake cause it to act like a liquid and more likely to subside when large weight is put upon it
Definition - Preparedness
Being ready for an event to occur (public awareness education, training)
Definition - Response
Immediate action taken after an event (evacuation, medical assistance, rescue)
Definition - Recovery
Long term responses (restoring services, reconstruction)
Definition - Mitigation
Strategies to lessen effects of another hazard (barriers, warning signals developed, observatories)
