Earthquakes

• Earthquakes occur in narrow bands which match the outlines of the earth's tectonic plates.
• They are caused by a sudden movement in the earth's crust.
• Most take place at plate boundaries.
• The place underground where an earthquake originates is called the focus.
• The point onthe surface directly above the focus is called the epicentre.
• A fault line is where a section of crust splits or cracks during an earthquake.
• Seismic waves are waves of energy that travel out from the focus during an earthquake.
• Earthquakes happen when two or more tectonic plates lock together due to friction.
• The forces moving the plates continue to apply pressure on the plates.
• This builds up until eventually the plates move without warning and the crust might split open.

• The Richter scale runs from 1 to 10 and measures the amont of energy released by an earthquake.
• The Mercalli scale runs from 0 to 12 and measures the amount of damage done by an earthquake.
• The Richter scale is logarithmic, each number being 10 times more powerful than the previous number.
• So an earthquake measuring 7 is 1 times more powerful than one measuring 6.

Primary Effects are the immediate effects of an earthquake. They include:

• Buildings collapsing.
• Liquefaction, where shaking causes water in the soil layers to be brought to the surface and buildings to subside.
• Objects falling from buildings and other structures, e.g. signs, glass and cables.

Secondary effects are the after-effects of an earthquake. They include:

• Fire and landslides.
• Tsunamis, such as the December 2004 tsunami that killed almost 300,000 people.
• Disease from unclean water supplies and lack of hygiene, such as typhoid and cholera.

Short Term Responses

• Emergency aid such as food, water, shelter and medical care.
• Specialist rescue teams with lifting machinery, sniffer dogs and heat-sensing equipment.

Long Term Responses

• Development aid to assist with the rebuilding and reconstruction of the affected area.
• Money to help businesses re-start
• Planning from local and national authorities to prepare for future earthquakes.

People can prepare for earthquakes in a number of ways:

• Predict where they might happen.
  • Geologists use seismometers to measure tremors that could indicate afuture earthquake.
• Prepare for when an earthquake happens.
  • Earthquake-prone countries run earthquake drills each year and peoplehave earthquake kits containing essential items for survival.
• Prevent damage during an earthquake.
  • Strict building regulations stop unstable buildings from being constructed.
  • New buildings in earthquake-prone countries have to be designed to be earthquake-proof.

• Earthquake that hit Haiti in January 2010 was 7 on the richter scale.
• Over 200,000 people were killed and over 300,000 people injured.
• Worst hit was the capital city, Port-au-Prince.
• A third of the buildings collapsed, making 1.5 million people homeless.
• The earthquake destroyed the country's port, airport, parliament, presidential palace and police headquarters.
• This made it hard for emergency help to get to Haiti.
• A poor country, Haiti did not have the resources to be well-prepared for an earthquake.
• It lacked the skilled people or equipment to respond effectively afterwards.

• An earthquake measuring 7.2 on the Richter scale hit Kobe, Japan, in January 1995.
• Out of 1.5 million, 5000 people died and 300,000 were made homeless.
• It caused over £100 billion of damage.
• 7500 houses collapsed and fires spread rapidly as gas pipes broke.
• Water mains fractured, making it hard to put out fires.
• An elevated road collapsed, as did sections of the bullet train track.
• A rich country, Japan has more than 1000 tremors every year, so people are used to earthquakes and know what to do.
• There are strict building controls and well-trained and equpped emergency response teams.