Geohazard & Geosource

• Geohazards


  • Volcanic eruptions
  • Earthquakes & tsunamis
  • Landslides
  • Sinkholes

  
• Volcanic eruptions


  • Lava flows & pyroclastic flows
  • Ash falls & tephra
  • Gas release: carbon dioxide, hydrogen chloride, hydrogen fluoride, hydrogen sulphide, sulphur dioxide

  
• Earthquakes


  Focus = hypocentre

  
• Measuring earthquakes


  1. Local earthquakes use ML – local magnitude scale

  2. Larger earthquakes use moment magnitude scale MW

  
• Logarithmic scale: 1 unit = a change of an order of magnitude (10x)
• Earthquake effects


  • Wajima, Japan - 7.5 magnitude, 100s of aftershocks, at least 62 dead, >300 injured, 10 000 homeless

  
• Tsunamis


  • Caused by earthquakes

  
• Landslides


  • Affected by: Volcanoes & earthquake activity, Water, Erosion processes, Steepness of slope, Rock type, Grain shape, Jointing and orientation of bedding planes, Arrangement of the rock layers, Weathering processes, Vegetation, Flooding, Human activity: mining, traffic vibrations or urbanisation
• Landslides


  • Berry Hill Quarry, Mansfield 2019
• Sinkholes


  • Caused by dissolution of soluble rocks like limestone and evaporites
• Karst


  Landscape shaped by dissolution of carbonate rocks, with underground sinkholes and cave systems, and surface features such as cenotes, limestone pavements, poljes
• Georesources


  • Fossil fuels
  • Mineral resources
  • Carbon capture
  • Renewable energy
• Fossil fuels


  • On the decline but still important
• Geothermal energy from old coal mines

  • Gateshead scheme - largest mine water heat network in Great Britain and one of the largest in Europe, heating Gateshead College, the Baltic Arts Centre, several offices and 350 council-owned homes
• 25% of homes and businesses in the UK are located above former coal mines
• Sustainability should underpin geoscience goals