Global hazards

• Hurricane Irma in 2017 had wind speeds of 300km/h due to the high pressure gradient of 274mb between the eye and eye wall
• Highest wind speed recorded in Wellington, New Zealand was 258km/h
• What is a Richter scale?


  measures the size of earthquakes based on seismometers. For every whole number increase, amplitude increases 10x and energy 32x
• Response to the Big Dry

  Multi million dollar desalination plant built in Sydney.
• Extreme weather, UK case study

  Boscastle flash flood, August 2004
• How was rainfall a physical cause of the Boscastle flood?

  70mm of rain fell in 2 hours
• Method of preparation for earthquakes


  In Japan National Earthquake awareness day is on 1st September
• Place where protection was used to mitigate impacts of a volcano

  Heimaey, Iceland 1973
• Technological developments used to mitigate impacts of a tectonic hazard

  Taipei 101 in Taiwan. Icelandic Meteorological Office (IMO) used 80 seismometers and 120 GPS antennas
• How is the severity of a volcanic eruption measured?

  Volcanic Explosivity Index (VEI)
• Tectonic hazard case study

  Eyjafjallajokull (E15) by the South coast of Iceland
• Causes of E15 eruption

  North American and Eurasian plate boundary is constructive, creating fissures on a composite volcano which erupted on 20th March 2010. Erupted again on 15th April.
• How was the global circulation system a physical cause of the Boscastle flood?

  Boacastle is at the meeting point of the Ferrel and Polar cell
• Hottest air temperature ever recorded

  Al-Aziziyah in Libya, 57.8 degrees celsius
• Where are volcanoes and earthquakes formed?

  Earthquakes formed on all plate boundaries, volcanoes formed on all except conservative
• Volcano found at destructive plate boundaries

  Composite
• volcano found at constructive plate boundaries

  Shield and fissure
• Volcanic gases

  Carbon dioxide and monoxide, hydrogen sulphide, sulphur dioxide, chlorine
• Physical cause of the Big Dry


  El Niño
• Human cause of the Big Dry

  Farmers along the Murray-Darling river took too much water, was allowed by New South Wales Government
• Consequences of the Big Dry

  Water bills rose by 20% in 2008 since there wasn’t enough water in the Murray-Darling basin. 10,000 people employed in the cotton growing industry were affected. Eutrophication in the Murray-Darling basin
• How is a dam a human cause of droughts?

  Gibe III on the River Omo in Ethiopia stopped water getting to Lake Turkana in Kenya
• Human causes of droughts

  Dams, overgrazing
• Physical cause of droughts

  Intertropical convergence zone (ITCZ) - an area of rain
• Extreme weather, non Uk case study

  Big Dry, Australia. Drought period from 2002 to 2009. Driest period in 125 years. Mainly affected Queensland and New South Wales
• Climate in Bundarra, New South Wales during El Niño compared to normal


  In January temperature is usually 30 degrees, in El Niño it’s 36 degrees. Usually 50-80mm of rainfall per month, in El Niño there’s 10mm
• Environmental consequence of Boscastle flash flood

  84 cars recovered from streets and harbour. 32 never found. Petrol and coolant could affect the sea life
• Economic consequence in Boscastle

  90% of economy dependent on tourism. More than 20 hotels and B&Bs forced to shut. Multiplier effect
• responses to the Boscastle flood

  7 helicopters from the RAF and Royal Navy saved 120 people. Sandbags used in shops and houses to absorb water. Environment Agency spent over £10 million on improvements
• Physical causes of Boscastle flood

  Topography - land was 80m high. Global circulation system - meeting of Polar and Ferrel cell. Rainfall - 70mm fell in 2 hours
• Responses to E15


  Route 1 damaged so National Emergencry Agency replaced bridges with prebuilt structures to reopen this major road. Icelandic Meteorological Office (IMO) used 80 seismometers and 120 GPS antennas to issue warnings
• Primary effect of E15 that caused international problems

  95,000 flights cancelled for a two week period
• Secondary effect of E15 that caused local problems


  Local water supplies contaminated with fluoride
• Secondary effect of E15 that caused national problems


  Flooding due to glacial meltwater destroyed Route 1
• Proposals made by Environmental Agnecy for flood defences

  Trees to be removed on B3263. River bed to be lowered 0.75 metres and widened