TECTONIC

• Hazard


  Potential threat to human life and property
• Natural Hazard


  Threat caused by climatic or land processes
• Geophysical Hazard


  Threat caused by land processes near plate boundaries
• Intraplate Earthquake


  Earthquake occurring away from plate boundaries
• Volcanic Hotspots


  Localized areas with high temperature due to molten material
• Magma


  Hot rock rising at volcanic hotspots
• Convergent Boundaries


  Locations where most powerful earthquakes occur
• OFZ (Oceanic Fracture Zone)


  Belt of activity through oceans and along mid-ocean ridges
• CFZ (Continental Fracture Zone)


  Belt of activity along mountain ranges from Spain to Himalayas
• Recorded Hazards


  Total number of documented hazards
• Fatalities


  Number of deaths resulting from hazards
• Mega Disasters


  Events with significant spikes in fatalities
• Insurance Policies


  Contracts that mitigate economic costs of disasters
• Direct Deaths


  Immediate fatalities from a disaster
• Indirect Deaths


  Fatalities due to post-disaster effects
• Tectonic Theory


  Study of Earth's lithosphere movements
• Crust


  Earth's thinnest, least dense outer layer
• Mantle


  Layer below crust, semi-molten with convection currents
• Outer Core


  Dense, semi-molten layer containing iron and nickel
• Inner Core


  Solid layer below outer core, high pressure and temperature
• Destructive Plate Boundary


  Plates where one subducts below the other
• Ocean Trench


  Deep trench formed by subducting oceanic plate
• Composite Volcanoes


  Volcanoes formed through explosive eruptions
• Fold Mountains


  Mountains formed by plate subduction
• Constructive Plate Boundary


  Plates moving apart, forming new land
• Sea Floor Spreading


  Formation of new land on ocean floor by magma
• Fault lines


  Cracks in the ground on continental crust caused by movement
• Oceanic crust


  Low-density rock, mainly basalt, thin, and newly created
• Continental crust


  High-density rock, mainly granite, thick, and old
• Density


  Determines plate subduction or forced uplift, impacting landscape and hazards
• Mantle Convection


  Radioactive decay in Earth's core produces thermal energy, creating convection currents
• Slab Pull


  Old, dense oceanic crust submerges into the mantle, pulling the plate with it
• Convection currents


  Previously thought primary cause of plate movement, now considered weaker than Slab Pull
• Earthquakes


  Sudden release of pressure between stuck plates, causing seismic waves
• Focus (hypocentre)


  Point underground where earthquake originates
• Epicentre


  Area directly above the focus on the ground
• Primary waves


  Travels through solids, compressional, vibrates in travel direction
• Secondary waves


  Vibrates perpendicular to travel direction, travels through solid rocks
• Love waves


  Near surface, rolling motion, vertical ground movement
• Rayleigh waves


  Vertical and horizontal displacement, slower than other waves