th key words

• accretion wedge 


  the accumulation of material at the point of subduction
• aseismic buildings 


  buildings designed to withstand or minimise destruction during an earthquake
• asthenosphere 


  the upper mantle layer of the earth. it is semi-molten and around 2000km wide
• ash


  fine particles and dust ejected during a volcanic eruption, which can remain as clouds or accumulate to the ground
• continental crust 


  crust that forms the continents of the litmoshpere, around 35km thick
• continental drift 


  the movement of plates due to varying weight of crust. it was originally thought to be convection currents that caused the movement, but now slab pull is believed to be the main primary force
• connection currents 


  the circulation of magma beneath within the mantle (asthenosphere). magma is heated by radioactive processes in the core and cools it at the surface, so it circulates between the two places
• Degg's model 


  this model shows that a hazard can become a disaster if it affects a vulnerable population
• epicentre


  the point at the surface, directly above the earthquakes origin
• focus


  the place in the crust where the pressure/seismic energy is released
• hazard mitigation cycle 


  the sequence of governance of a natural hazard: Monitoring and prediction, mitigation and preparedness
• hot spot


  volcanos found away from a plate boundary, due to magma plume closer to surface
• jokulhaup


  a sudden glacial flood, caused by a volcanic eruption melting it
• lahar


  a flow of mud and debris
• lithosphere 


  the upper crust of the earth, typically 100km think
• love wave 


  a surface earthquake with horizontal displacement
• mid-ocean ridge 


  parting oceanic plates at a constructive plate boundary creating a ridge, with new land at the oceanic valley
• oceanic crust 


  crust, usually thinner than continental crust (typically 7km thick)
• Park's model 


  a model describing the decline and recovery of a country over time, following a natural disaster
• partial melting


  elements within the lithosphere have different melting points, and so rock is partially melted and partially solid
• primary waves


  an earthquake wave causing compressions within the body of rock
• pyroclastic flow 


  a mixture of gases and rock fragments, at high temperatures travelling at rapid speeds
• Rayleigh waves 


  a surface earthquake causing both horizontal and vertical displacement
• richer scale 


  a measure of earthquakes intensity
• secondary wave


  an earthquake wave causing vertical displacement within a body of rock
• seismic waves 


  the energy released during an earthquake, in the form of primary, secondary, love and Rayleigh wavs
• slab pull 


  the force contributing to the movement of tectonic plates. this is due to the weight to the plate
• subduction


  the oceanic plate is forced below the continental plate, due to the oceanic plate being more denser than the continential
• tsunami


  vertial water displacement (often due to under water earthquakes), creating waves with large destructive power
• volcanic explosively index (VEI)


  the measure of the magnitude of a volcano's explosion
• volcanic island arc


  a series of volcanos (often in the shape of an arc) that are formed, as tectonic plates move across a magma plumes
• Wadati-benioff zone 


  a reigon of the subducting plate, most affected by pressure and friction, where most destructive plate margins originate
• resilience 


  the ability to protect lives, livelihoods, and infrastructure from destruction, and to restore the area after a natural hazard has occurred
• risk


  the exposure of people to a hazardous event. it is the probability of a hazard occurring that leads to the loss of lives and/or livelihoods
• vulnerability 


  the ability to anticipate, cope with, resist and recover from a natural hazard
• development


  linked to improving society, enabling people o achieve their aspirations. it includes the previsions of social services, acquisition of economic assets, improved productivity and reducing vulnerability to hazards. low levels of development are closely associated with high levels of risk and vulnerability to natural disasters
• inequality 


  an unfair situation or distribution of assets and resources. it may be used when people or nations and non state players have different levels of authority, competence and outcomes
• governance


  the sum of many ways individual, institutions, public and private manage their common affairs. it is a continuing process through which conflicting or diverse interests may lead to accommodated and co-operative action may be taken
• intra-plate


  relating to or occurring within the interior of a tectonic plate
• mantle plume


  there are two huge mantle plumes (Pacific and African); these are hotter areas if the mantle that moves upwards underneath the crust and push it up. they can cause weak points in the crust which can become hot spots