Unit 1 - Natural Hazards

Hydro-Meterological Hazards: Caused by climate processes (Drought, Floods, Hurricanes)

Geophysical Hazards: Caused by land processes (Earthquake, Volcanoes, landlslides)

Human

• Rapid poulation growth + urbanisation means = Higher population density 
• Increasing global poverty = lack of clean water and weak economies
• Exploitation of resources such as deforestation increases flooding and lanslides
• More media coverage gives the impression of increased frequency
• In LEDCs poor people are forced to live in more at risk areas 

Physical 

• Impact of global warming is thought to increase magnitude and frequency
• El Nino can change weather patterns making hazards more unpredictable

• Improved prediction technology menas people can be evacuated
• Prevention methods to stop a hazard becoming a disaster
•  Educating people to be prepared in the event of a hazard

• Disaters in MEDCs cost more becuase they have more expensive infrastructure to be affected
• People in MEDCs tend to have insurance in the event of a disaster which insurance companies then have to pay out, driving up the economic loss
• As countries become more globalised tourism becomes a source of income, a disaster could give the impression that the country is unsafe and will loose tourism revenue 

• Occurs when two plates move apart 
• As the plates move apart the mantle is melted producing magma 
• They move at inconsistant speeds that build up pressure, when the pressure is too great the plate cracks leading to an earthquake and a faultline being formed. more earthquakes can occur along this faultline

• Occurs when two plates move towrds each other 
• The denser plate (usually oceanic) is forced under in a process called subduction 
• The oceanic plate is heated by friction and the upper mantle melts, becoming magma
• The magma then rises to the surface to form a volcnao 
• As one plate moves under the other they can become stuck causing pressure to build up, when the pressure becomes to much the plates jerk causing an earthquake 
• If two continental crusts collide neither is subducted but preasure builds, causing an earthquake

• Occurs whentwo plates are moving past each other
• The plates become locked and pressure builds, they then either jerk or crack and form a faultline, both result in an earthquake

Basic information

• Population: 38 million 
• GDP Per Capita: $52,000

Earthquakes

• San Andreas faultine runs the lenght of california and is a conservative plate boundary 
• Experiances abround 3 earthquakes a year over 5.5 magnitude
• predictions are that by 2025 a 7.0 earthquake will hit the San Francisco bay area
• The last Earthquake was in 1989

Drought

• Caused by Anticyclonic conditions (High pressure)
• La Nina also brings dry conditions 
• wildfires are common as a result of the dry atmosphere, in 2007 22 were killed in a wildfire

Tsunami

• Casued by underwater earthquake or landslide
• The 1964 Alaskan Tsunami killed 12 in California

Flooding & Landslides

• Flooding caused by heavy precipitation in the San Joaquin river
• Lanslides cause costal erosion, extreme rain or earthquakes 

Vulnerability 

• 70% of the population live within 50km of a faultline
• Soil liquefaction is an issue during earthquakes 
• Buildings on the coast are vulnerable to storms and Tsunamis
• In LA 20% of residents live below the poverty line
• Large economic losses may take years to recover from 

Basic information

• Population: 93 million
• GDP Per Capita: $4,000
• Destrucitve Plate 

Earthquakes, Tsunamis & Volcanoes

• A 7.8 Earthquake in Luzon in 1990 killed 1500 people
• A Tsunami in 1976 killed 7000 people on Mindanao Island
• Mt Pinatubo erupted in 1991 with a VEI 6 and killed 800 homeless

Landslides

• Due to heavy precipitation landslides are common
• Earthquakes can also trigger landslides
• In 2006 a landslide in Leyte killed 1100 people

Typhoons

• Experiances around 10 typhoons a year
• 2006 Typhonn Xangsane killed 250 people
• Typhoons can also trigger Landslides,Lahars and costal flooding 

Droughts

• Dry season lasts from November to April 

Vulnerabilities

• Realativley poor so low capacity to cope
• Population pressure has led to deforestation 
• A majority of the population are forced to live on $3 or less a day
• Poor preparedness with few emergency services and hospital beds
• Many live in inaccessible locations