Geography paper 1 - physical

• A natural hazard is a natural process which could cause death, injury or disruption to humans or destroy property and possessions
• a natural disaster is a natural hazard that actually happens
• extreme events which do not pose any threat to any human life are not counted as hazards e.g. droughts in a desert or avalanche in Antarctica
• geological hazards are caused by land and tectonic processes which include volcanoes and earthquakes
• meteorological hazards are caused by weather and climate which include tropical storms and other extreme weather
• hazard risk is the probability of people being affected by a hazard in a particular area which is affected by vulnerability , capacity to cope and nature of natural hazards
• VUNERABILITY. the more people that are in an area exposed to natural hazards, the greater the probability they will affect by a natural hazard hazard. also, an area with a high population density on a flood plain is very Vulnerable to flooding caused by extreme weather and a city at the base of a volcanoes like Naples is very vulnerable to volcanoes eruptions
• CAPACITY TO COPE. the better a population can cope with an extreme event the lower the risk of them being affected. also, high income countries are better able to cope with flooding because they can afford to build flood defences and evacuate people
• NATURE OF NATURAL HAZARDS. type of risk is greater than other because storms can be predicted giving people a chance to evacuate but earthquakes are sudden. also frequency of natural hazards that occur more often may carry a higher risk. also, magnitude the more serve natural hazards tend to have greater impacts
• primary effects of natural hazards : buildings destroyed , death or injury and access to roads, electricity and communication networks can be damaged
• secondary effects of natural hazards : aid and emergency cant get through because of blocked roads which cause more deaths, a shortage of clean water and food and lack of sanitation
• immediate response of natura hazards : evacuation, aid and treatment, recover of dead bodies, temporary supply of gas and electricity and shelter
• long term responses of natural hazards : repair of buildings, rehousing, reconnect broken electricity, water and gas, improve building regulations so they can withstand future hazards
• continental crust is thicker 30-50 km and less dense
• oceanic crust is thinner 5-10 km and more dense
• plates move because of convection currents in the mantle
• where plate meet are called plate margins or plate boundaries
• destructive plate margins : two plates are moving towards each other where an oceanic plate meets a continental plate, the denser oceanic plate is subducted and destroyed creating magma. volcanoes and oceanic trenches happen here
• constructive margins : constructive margins are where two plates are moving away from each other. magma rises from the mantle to fill the gap and cools creating new crust
• conservative margins : conservative margins are where two plates are moving sideways past each other, or are moving in the same direction but at different speeds. crust isn`t created or destroyed
• volcanoes occur at destructive and constructive plate margins : at destructive margins the denser oceanic plate moves down into the mantle where it melts. a pool of magma forms, which then rises through the cracks in the crust called vents. the magma erupts forming a volcanoes. at constructive margins the magma rises up into the gap created by the plates moving apart forming a volcanoes
• earthquakes can occur at all three types of plate margin : destructive margins, tension builds when one plate gets stuck as it moves past the other. constructive margins, tension builds along the cracks int he plates as they move away from each other. conservative margins, tension builds up when plates that are grinding past each other get stuck
• after tension forms, the plates eventual jerk past each other sending out shock waves these are the earthquakes. the shock waves spread out from the focus the point in the earth where the earthquake starts. the waves get stronger near the focus and cause mor damage . the epicentre is the point on the earths surface straight above the focus
• The Richter scale measures the magnitude of an earthquake (how powerful it is). It is measured using a machine called a seismometer which produces a seismograph. A Richter scale is normally numbered 1-10, though there is no upper limit.
• new Zealand suffered a 7.8 magnitude earthquake in 2016 on the 14th of November
• new Zealand earthquake primary effects : 2 died, 50 injured, tens of thousands home destroyed, 60 people needed emergency housing, it cost $8.5 billion and destroyed 190km of railway
• new Zealand earthquake secondary effects : triggered up to 100000 landslides, a major landslide blocked the clarence river leading to the flooding and evacuation of 10 farms and it generated a tsunami with waves of 5m leading debris up to 250m inland
• Nepal suffered a 7.8 magnitude earthquake in 2015 on the 25th of April
• Nepal earthquake primary earthquakes : 9000 people died and more than 22000 were injured, 800000 buildings were damaged or destroyed, 4 million were left homeless and the damage cost $5 billion
• Nepal earthquake secondary effects : triggered an avalanche on mount Everest that killed 18 people , mountain rads were blocked by landslides preventing emergency aid and a lack of clean water caused outbreaks of typhus which killed at least 13 people
• new Zealand immediate responses : tsunami warning issued quickly and residents near costal areas were told to get to high ground , 200 of the most vulnerable people were evacuated from Kaikoura by helicopter and international warships were sent with supplies such as food medicine and water
• new Zealand long term responses : $5.3 million of funding was provided, most road and rail routes were rebuilt within 2 years and in march 2017 a new water main was laid which is designed to withstand earthquakes
• Nepal earthquakes immediate responses : India and China sent teams to help residents rescue trapped people but lack of tools and machinery slowed down rescue efforts, people tried to recover the dead and treat the injured but damaged roads mad it difficult and the red cross set up 130000 families were given emergency housing
• Nepal earthquakes long term response : the world bank group financed $500 million worth of projects to build earthquake resistant housing, the road from Nepal and Tibet was reopened within 2 years and many heritage sites were reopened in june 2015 to encourage tourist back into the area
• MONITORING : seismometers and lasers monitor each earth movement and can be used in early warning systems to give a small but vital amount of warning before a large earthquake occurs, volcanic eruptions, scientists can monitor and the tell tale signs that come before an eruption such as tiny earthquakes, escaping gas and changes in the shape of the volcano
• PREDICTION : earthquakes cannot be reliably predicted but scientist can forecast where they may occur by monitoring the movement of tectonic plates, volcanic eruptions, can be predicted if scientist monitor volcanoes closely
• PROTECTION : earthquakes , new buildings can use reinforced concrete that absorb concretes energy. existing buildings and bridges can be strengthened with steel frames so they are less likely to collapse. automatic shut off switches can turn off gas and electricity supplies to prevent fires. volcanoes, buildings can be strengthened so they are less likely to collapse under the weight of the ash. trenches and barriers have been used to prevent and divert lava away from settlements but with little success
• PLANNING : future developments can avoid high risk areas, emergency services can prepare, people can be educated so they know what to do in the event of a hazard and governments can plan escape routed for people
• cool air sinks
• hot air rises