Hazardous Earth

• Jigsaw fit

  -Africa and South America

  -Affected by sea level and erosion
• Fossil evidence

  -Mesosaurs in Africa and South America - doesn't cross salt water
• Geological evidence

  -Rocks in New York, Scotland and Scandinavian
• Climate evidence

  -Glacial striations found near equator - Used to be further north and south
• Palaeomagnitism

  -Mid oceanic ridge in Atlantic

  -Basaltic crystals point north

  -Changes every 500,000 years
• Constructive (Apart) Pacific and Nazca
• Destructive (Together) Eurasian and Indo-Australian
• Conservative (Side to side) Juan de Fuca and North American
• Constructive - Mid oceanic ridge and rift valley
• Conservative - fold mountains and faults
• Destructive - Deep sea trench and volcanic island arc
• Intrusive Volcano Feature

  -Didn’t make it to surface

  Sills, dykes and batholiths
• Sills - horizontal, cracks in bedding plane in sedimentary rock
• Dykes - vertical, igneous rock
• Batholiths - Solidified magma chamber
• Fumeroles - Pipe is wider than geyser - only steam
• Boiling mud - Geysers with clay at surface - not just one vent
• Features of explosive

  -Convergent, Rhyolite and andesitic, low viscosit, low temp when erupting

  -Gas, dust, ash, lava bombs and tephra

  -Long periods of time with no activity

  -Steep sided stratovolvano
• Features of Effusive

  -Divergent, basalt, low viscosit, high temperature

  -Gas, lava flows,

  -More frequent eruption

  -Gently sloping sides
• VEI shows ejects descriptions and characteristics allowing volcanoes to be ranked from 0 to 8
• AA

  Dries with air inside - carries clinkers - more viscous
• Pahoehoe

  Looks ropey, moves slower
• Destructive power of a volcano

  -Time since last eruption - pressure

  -Plume height

  -Viscosity

  -Wind direction

  -Magnitude

  -Ejecta type
• Super volcanoes

  -1,000km^3 of ejecta

  -Caldera

  -27,000 years ago - Taupo NZ

  —10*c, 10% less sunlight
• YELLOWSTONE USA

  -75km diameter

  -1.3 million and 640,000 years ago

  -Ash over west America

  -Overdue eruption, prediction impossible

  -Magma chamber increased 400%

  -Last eruption 70,000 years
• Temperature rise

  -Heated gas, water and soil

  -Ground drier, groundwater evaporate, shown in plants
• Harmonic tremor/Seismic activity

  -Measured by seismometer - read on seismograph

  -Magma flows through conduit causing friction
• Gas emissions

  -Pressure keeps gas trapped in magma

  -Gas released when magma rises

  -Crops brown - Sulphuric acid
• Ground deformation

  -Magma chamber inflates

  -Tiltmeter of sides record changes

  -May cause landslides
• Satellite tracking

  -Detection from space

  -Computers estimate material amount and flow
• Earth blocks deposited to divert lava flow
• Channels dug to divert lava flow
• River channels clear of debris for lahars
• Risk = frequency and magnitude of hazard x level of vulnerability/ capacity of population to cope
• Park’s Disaster Response Curve

  1. Quality of life normal - Preparing
  2. Quality of life drops - Protection and prevention
  3. QOL stops decreasing - Medical and rescue
  4. Rehabilitation - Provide food and water
  5. Reconstruction - Improve on mistakes
• Seismic activity

  —Magma rises - pressure on stress fractures to find route to surface

  -Avalanches and landslides
• Floods / Jökulhaup

  -Rapidly melting because of Eruption under ice sheets

  -Water accumulates under ice
• Toxic gases

  -Combines atmospheric water and creates acid rain

  -Co, Co2, SO2
• Tephra

  -Any material into air

  -Fine ash to volcanic bombs

  -100,000 cancelled flights
• Lahar

  -Mud flow - snow and ice from volcano summit

  -Colombian town 23,000 deaths