Responses to Hazards 3.1.5 - Reduce Vulnerability - Mindmap in A Level and IB Geography

Created by: l.bracey2000
Created on: 03-02-17 10:18

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Responses to Hazards 3.1.5 Reduce Vulnerability
- Prediction and warning
  - Predicting volcanic eruptions
    - Seismicity
      - Short Period Earthquake
        Caused by the fracturing of brittle rock as magma forces way upwards
        Signify the growth of magma body near the surface
        These are 'A' waves
      - Harmonic Tremor
        Result of magma pushing against the overlying rock below the surface
        Sometimes strong enough to be felt as humming or buzzing by people and animals
        E.G Used very successfully at Popocatepetl, Mexico
      - Long Period Earthquake
        Indicate increased gas pressure in a volcano plumbing system
        Similar to the clanging sometimes heard in a housing plumbing system
        These are 'B' waves
    - Gases
      - As magma nears the surface and its pressure decreases, gases escapes
        Sulphur Dioxide
        Increases indicates the arrival of magma to the surfaace
        E.G Strategy used at Pinatubo (May 13, 1991) increases in SO2
        May 28, increased to 5,000 tonnes, 10 times greater than earlier amount
      - SO2 emissions at low levels
        Caused by sealing of gas passage ways by hardened magma
        Increased chance of an explosive eruption
    - Ground Deformation
      - Swelling: magma has accumulated near surface
        E.G Monitoring Sakurajima (Kyushu, Japan)
        Most monitored areas on earth Kagoshima City, which has a population of 500,000 people
        Unexpected high tide levels
        Signalled by swelling of the land around the volcano as magma begins to build up
        
        Underground observation tunnel and seismometers
        Detect earthquakes up to 5 km around mountain and also below crate
        
        Temperature sensors check for changes in temperature of hot springs
        They are placed in bore holes used to detect ground water temperature
        
        Remote sensing for gases as ratio of HCl to SO2 gas increases significantly before an eruption.
      - Scientists can measure the tilt of a slope
        Track changes in the rate of swelling
        E.G Mount St. Helens - North side of the volcano was bulging upwards as magma was building up underneath
        
        Tilt metres measure minute movements of the mountain
      - E.G San Andreas Fault
  - Response Period is the time between eruptions
    - Can indicate the size of the eruption
      - E.G Mount Etna, Italy. Long period, there was a large and explosive eruption
  - Earthquake activity
    - Shows magma below the volcano is moving
  - Change in surface shape
    - This shows the magma rising beneath the surface
      - Leading to a bulge of the surface
        E.G Mount St Helens, USA
  - Changes in volume or type of volcano gases
    - If amount decreases can indicate a blocked vent
      - E.G Mount Pinatubo, Philippines
      - E.G Christchurch, New Zealand
  - Gases emitted at or near a volcano
    - SO2 may show that new batch of magma has arrived at depth
  - Earthquake Prediction
    - Foreshocks
    - Ground Deformation
    - Unusual animal behaviour
    - P and S wave ratio
    - Water and radon levels in wells
    - Levels of manganese, zinc and copper in basaltic rocks
    - Monitoring how fast strain accumulates
    - Changes of electrical magnetic properties of rock
      - Monitoring with satieties electrical charges
- Examples of earthquake prediction
  - Van, Turkey
    - 7.4 magnitude earthquake in 2011, lasting for 45 seconds
      - 25,000 people died
      - People didn't react to technology signs
      - North Anatolian Fault runs in a relatively straight line
    - Computer model alone the fault line
      - Showing a pattern from looking at past earthquakes
      - Predicting stress east to wets
  - L'Aquila, Italy
    - 6th April, 2009. Magnitude 6.3 earthquake
    - Public meeting 6 days prior to the shock
      - Members of Italy's Great Risk Commission down played the risk
        People were not made aware of the likelihood of the disaster
    - Amateur seismologist, Giampaolo Giuliani
      - Predicted a major quake
        Based on radon readings on his home made monitoring devices
    - 22nd October 2012, 6 scientists and one ex-governmemt official
      - All were at the meeting
      - Found guilty, for playing down the events, of manslaughter by an Italian judge
        Sentenced to 6 years in prison
- Pitfall to prediction and risks
  - Competing risks and priorities
  - Uncertain and difficulty with prediction
  - Unease with scientific jargon
  - Lacking emergency response infrastructure
  - Too many false alarms
- Community preparedness
  - Land Use Planning and Zoning
    - Maps for soil liquefaction susceptibility and shaking intensity
      - E.G San Fransisco - liquefaction maps
        Shows where the hard rock is
        
        Therefore where to build skyscrapers
    - Volcano hazard maps
      - Pyroclastic flow and lateral blast hazard map.
      - Lahar hazard zones map
      - E.G Mount Shasta, USA
      - E.G Pinatubo, Philippines
      - E.G Montserrat, Caribbean
  - E.G Japan and California
    - Regular earthquake days
      - People practice evacuating buildings, fighting fires, coping with smoke filled rooms
  - E.G Japan
    - Grab bags, which for example would include first aid, sleeping bags, torch
      - Found in homes, businesses and schools
  - Remembering past events, using it as a warning
    - E.G Japan
      - Hundreds of centuries-old tablets as reminders of tsunamis
  - Evacuation E.G Mt St Helens evacuation in 2004
    - Reduce death toll as direct certain areas to certain road
      - Avoids congestion

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Responses to Hazards 3.1.5 - Reduce Vulnerability

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