hazards

• constructive plate margin

  constructive plates move apart due to convection currents. magma rises upwards through the gap thats been created. leads to formation of volcanoes as the layers of lava build up, establishing the volcano .

  Earthquakes + Volcanoes happen in this margin
• destructive plate margin

  destructive plates move towards each other due to convectional currents . when an oceanic plate meets a continental plate the oceanic is forced under the continental plate as its more dense, into the mantle where it melts. hot magma can rise through the lithosphere and erupt as lava via volcanoes.

  Occurs in : Earthquakes and Volcanoes
• conservative

  Conservative plates slides parallel past each other , this creates fiction and pressure builds up as the movement is not smooth. the stress eventually overcomes the frictional resistance causing the sudden release of energy, thus generating the earthquake. the earthquake occurs at the focus but is felt at the epicentre. no volcanoes are made here as theres no area created for the magma to come through.

  Earthquakes happen in the plate margin.
• Global distribution of earthquakes + volcanoes relating to plate margins

  the distribution isn't random

  they occur in narrow bands along plate margins

  found both on land and in sea.

  earthquakes are found at all 3 types of plate margins

  some anomalies as some occur in the middle of plates in 'hot spots'
• short term responses are those that happen quickly following a disaster and aim to save lives, short term responses can include providing emergency aid in the form of food/ water and tents as well as deploying search + rescue teams and setting up field hospitals.
• short term responses are important as they directly address the immediate needs of the community eg: by giving emergency supplies like food/water. this is essential as it prevents loss of life. they also prevent prolonged suffering by providing people with emergency accomodation.

  however this aid can be challenging to distribute if transport links are cut up, there might not be enough help to support a population of suffering people + may be slow if countries rely on international help.
• long term responses are those that happen later on after the disaster and aim to help redevelop the area. these responses include rebuilding infrastructure to a higher standard, providing financial support to businesses + offering cancelling to locals.
• long term responses are important to minimise future risks -eg: if houses are built back to a better standard they will be more likely to withstand future earthquakes + result in less deaths. also long term responses such as restoring gas, water + electric cables are essential so people dont go without essential supplies for too long that help to make homes + businesses run effectively. however, long term responses are expensive, take a long time to complete + may not extend to the whole community.
• primary effects are the impacts that typically happen within minutes, hours/ days after the earthquake. these include damage to infrastructure, deaths , panic + road closures.
• secondary effects are those which are caused after the shaking has stopped but are result of the earthquake. these are the impacts that typically happen weeks , months or years after the earthquake. these include diseases spreading from dead corpses, landslides/tsunamis, trauma + business closures.
• seismic waves record the waves made by earthquakes
• once the waves have been recorded it corresponds to a number on the richter scale which measures the magnitude of the earthquake.
• monitoring


  using weather forecasts to track weather fronts

  using seismic waves to record earthquake activity (foreshocks).

  using insrtruments to detect changes in a volcanoes shape as they swell before they erupt

  using instruments to detect gases released from volcanoes
• prediction

  observing historical evidence gathered from past events to determine if the hazard is 'overdue'.

  monitor the volcano + then predict whether the signs show it might erupt. This is challenging for earthquakes as there arent many warning signs of when and where it could happen.
• protection

  construct buildings + bridges to resist the ground shaking associated with hazards.

  Construct tsunami walls to protect people + buildings.

  order evacuations as can be easy to outrun lava flow

  establish emergency centres
• planning

  creating hazard maps of the most dangerous volcanoes or likely places to experience earthquakes and stop people from living in these zones.

  creating evacuation plans in the event of a natural hazard occurring.

  training a local emergency response team

  educate locals on the hazards and conduct drills.
• People live near hazards because

  Cost of living can be lower to hazards

  volcanic soil is very fertile, which makes it good for farming, so farmers often live on volcanic slopes.

  eruptions and earthquakes can be infrequent and so do not pose a regular large risk

  some people do not understand the risk (lic)

  there are many plate boundaries around the world + can be difficult to avoid.

  people have learned to accept the risk that are exposed to

  tectonically active areas can provide opportunities for generating geothermal energy.