GEOGRAPHY CHAPTER 5

Location of earthquakes and vocanoes: world divided into 7 plates. Two types of plate oceanic and continental. In the seperation of plates if where activity occurs as the earth is unstable here.

Destructive plate margins: plates move together. Two types : collision and subduction zones. Collision is where they hit head on and buckle going up forming a volcanoe. Subduction is when the oceanic goes under continental. Build up magma. pressure. Volcano.

Constructive Plate margins: plate move apart and magma fills the gap.

Conservative: two plate slide past each other causing pressure. Earthquake!

Why live in hazardous areas?

• Good physical and economic activities - climate and jobs
• fertile soils - volcanic rock
• mineral extraction - volcanic areas
• opportunitty to geneerate geothermal energy - volcanic
• development of tourism

Earthquakes: measured on Mercalli Scale, determines how much the earth is shaking and its likely effects and the Ricter Scale measure the energy on a scale of 1 to 10.

Effects: Primary = deaths, injury, damage to buildings, infraastructure

Secondary = fires, spread of disease, food, water, shelter, medical facilities

Why do earthquakes effect areas in different ways?

• distance to epicenter
• type of land
• time
• how prepared an area is

Preparing For Earthquakes:

• educate
• drills
• train fire services
• stronger buildings - rubber shock absorbers
• gas electricity etc in flexible pipes

Volcanic eruptions produce:

• lava flows
• ash falls
• materials
• toxic gas
• mudflows

How can they be predicted?

• small tremors
• bulging cracks in volcano
• ground temperature increases
• small ash eruptions
• changes in gases
• hazard zoning
• educate
• drills

Colombian Earthquake Jan 1999

• deaths
• homes lost
• injuries
• water electricity cut off
• roads destroyed
• hospitals damaged
• fleet of fire trucks destroyed
• outbreaks of disease
• Sent for aid from other countries
• Effects so great because: poorly built buildings, unexpected, untrained, poor area, no water for days, homeless, industries destroyed

MT ST HELENS 18 MAY 1980

• dESTRUCTIVE PLATE MARGIN
• monitoring gave a warning
• landscape flattened
• farmland lost but better long term fertile soils
• forestry flattened replanted trees later
• communications lost
• flooding
• fish died in lava flows
• tourism brings money

KOBE 7.2 ON RICTER SCALE JAN 1995

• morning
• 600 after shocks
• 6000 deaths
• 35000 injuries
• homes destroyed
• water, gas electricity disrupted
• fires
• high rise building demolished
• jobs lost
• more jobs made in rebuilding city

NOW:

hazard zoning, strong buildings, fire resostant, increased monitoring of earthquake.