Associated Hazards

• Ground shaking: Horizontal and Vertical movements (P-S waves)

  3 Severity factors: Magnitude, Geology, Epicentre Proximity

  1985 Mexico city: Severe EQ due to these conditions (high MG, saturated, alluvium geology and close to epicentre)

  Dilatancy might act as a response to lower the severity
• Ground shaking: impact

  Stability of buildings is affected more by swaying (horizontal) than vertical movements

  Mitigations: protection through reinforced structures (Pendulum power), flexible foundations and shock absorbers at base

  But ground displacement destroys infrastructure (roads, railways and pipelines) as well as streams/rivers causing problems in water supply and services (transport)
• Liquefaction: The process by which soil becomes loose and flows like a liquid.
• Liquefaction: Saturated, alluvium and fine-grained sand behave like liquids seismic vibrations. This causes the surface to lose strength: buildings and roads collapse and sink (Sulawesi Indonesia, 2018 EQ)

  Depends on geology
• Landslides/avalanches:

  Steep slopes. deforested areas, monsoon rain increases vulnerability and risk

  They bock transport routes, rivers and cause temporary dams which burst and flood downstream (2005, Kashmir)

  They can overwhelm reservoirs upland as displaced water overtops/breaks through (1963 Vajont/Vaiont reservoir, Italy produced a 100m wave that inundated Piave river valley drowning 3000)
• Tsunami: Waves of up to 200km wavelength, speeds of up to800km/hr caused by sudden displacement of water
• Tsunamis are caused by submarine earthquakes but can also be caused by landslides, explosions and meteorites. As plates rebound after friction a column of water spits into ripple of waves; they gain height in shallow water and break after a drawdown of water occurs.
• Impacts of tsunamis

  Damage to property, possession and infrastructure, death and tragedy, disease, demand for necessities and psychological loss. e.g. case study of 2011 Tohoku, japan
• Severity factors of Tsunamis

  Scale/Intensity

  Unaware/unpreparedness

  Coastal relief

  Pop Density

  Funding/level of development

  Alerts/warning systems