Earthquake 2

• Earthquakes


  Vibrations caused by earth movements at plate boundaries and at major fault lines (cracks in the earth's surface)
• Earthquakes


  • They can occur at all four major plate boundaries but the most severe earthquakes are normally found at conservative and destructive plate boundaries
• Destructive plate boundary


  Plates move towards each other and one is pushed under the other
• Conservative plate boundary


  Plates slide past each other
• Richter Scale


  Measures the magnitude of a tremor (how powerful it is) using a seismograph. It is a logarithmic scale where each whole number increase represents a 10-fold increase in magnitude.
• The largest earthquake ever recorded was in 1960 in Chile, measuring 9.5 on the Richter Scale
• The Japanese earthquake in Kobe (1995) measured 7.2 on the Richter Scale


  It was 10 times more powerful than the Greek earthquake (1995) which measured 6.2
• Mercalli Scale


  Measures the amount of damage caused by an earthquake based on observations, on a scale from I to XII

  
• Epicentre


  The point on the earth's surface directly above the focus (where the rock movement occurs)
• Focus


  The point at which the rock moves, where the seismic waves start
• Predict


  Water levels can rise, foreshocks can be detected, animals can act strangely before the earthquake
• Plan and protect


  Have an emergency kit, design earthquake-proof buildings, have building regulations in earthquake zones
• Factors affecting earthquake damage include size of earthquake, time of day, emergency services, building design, education, and physical landscape
• Tsunamis are tidal waves triggered by underwater earthquakes, which can travel at 400-600 miles per hour
• The 2004 SE Asian tsunami was triggered by a 9.0 magnitude earthquake off Sumatra, and killed around 290,000 people