tectonic hazards

• what is a natural hazard?

  a natural process which could cause death, injury or disruption to humans, property and possessions
• what was the magnitude of the Hati earthquake?

  7
• how many people died in the Hati earthquake?

  300,000 people
• what were some of Hatis earthquake secondary effects?

  1.5 million in temporary accomodation

  2 million people without food or water

  outbreaks of cholera

  lots of crime and looting
• what were Hatis earthquake immediate responses?

  charity donations, search and rescue sent and the USA sent 10,000 troops
• what were hatis long term responses?

  new homes and temporary accommodation built to a higher standard and waived debt
• what was the magnitude of Christchurch earthquake?

  6.3
• how many people where injured and died in the Christchurch earthquake?

  over 100 deaths and 3000 injured
• what are the secondary effects of the earthquake in christchurch?

  businesses closed, couldn't host rugby World Cup matches, schools closed and 1/5 of locals migrated
• what were the immediate responses for Christchurch?

  international aid, aid workers and areas were zoned to access damage
• what were the long term responses of christchurch?

  water and sewage restored and affordable housing built with temporary homes
• what happens at a destructive plate margin?

  the denser plate subducts beneath the other, friction causes it to melt and become magma. this magma then forces its way up to the surface to form a volcano
• what happens at a constructive plate margin?

  two plates move apart causing new magma to reach the surface. volcanos then form along this crack causing a submarine mountain range
• what happens at a conservative plate margin?

  the plates slide past each other in opposite or the same direction at different speeds. this causes earthquakes
• how is an earthquake formed?

  when two plates become locked causing friction to build up. the pressure will eventually be released, triggering the plates to move into a new position. this movement causes energy in the form of seismic waves to travel from the focus towards the epicentre. the crust then vibrates triggering an earthquake
• what is the point at which the pressure is released?

  the focus
• what is the point directly above the focus?

  the epicentre
• what are the energy waves that travel out from the focus?

  seismic waves
• the crust is divided into tectonic plates which are moving due to convection currents in the mantle
• how do convection currents work?

  -radioactive decay of some elements in the core and mantle generate heat

  -lower parts of the mantles molten rock heat up and become less dense so rise

  -as they move to the top they cool down and become more dense and sink

  -these are convection currents that create drag on tectonic plates which causes them to move
• what are the monitoring techniques for earthquakes?

  seismometers, thermal imaging(this sects heat around the volcano)and gas samples can be taken
• what is the preparation for volcanoes?

  creating an exclusion zone around the volcano, good emergency services and having basic provisions ready
• how do you protect against earthquakes?

  building resistant buildings, raising public awareness and improving prediction