tectonics

• What is it called when the earthquakes occur within the plates and not on the boundaries?


  intra-plate and hotspots
• How do hotspots occur? (2)

  - the upwelling of hot molten material from the core/ mantle boundary (like Hawaii)

  - the top of a huge mantle plume just under the crust
• What is the process of tectonic plates moving?

  - convection is created in the mantle by heat radiating outwards from the inner core, due to radioactive decay

  - the mantle material is under pressure due to depth and when heated behaves like a viscous liquid.

  - heat derived from the Earth's core rises within the mantle to drive convection currents, which in turn move the tectonic plates. These convection currents operate in cells

  - Where mantle convection cells make contact with the base of the crust they move the plates by frictional drag or slab pull
• What is a supervolcano? and example

  Yellowstone in the USA have large calderas and very long time periods between eruptions, but when they do they can have a big impact on the world
• What are the three main types of lava/ magma?

  - basalt

  - andesite

  - rhyolite
• What are the characteristics of a composite volcano? (5)

  - steep sided

  - narrow base

  - alternating layers of ash and lava

  - magma from a magma chamber so is more likely to be from melted oceanic crust

  - magma is andesitic
• What are the characteristics of a shield volcano? (5)

  - wide base

  - gentle slopes

  - magma rises directly from the mantle

  - magma is basaltic

  - they have more gentle eruptions
• What are the primary hazards of a volcanic eruption? (4)

  - lava flows

  - emissions of gases and steam

  - tephra (ash, volcanic bombs)

  - pyroclastic flows
• What are the secondary hazards of a volcanic eruption? (2)

  - lahars

  - jokulhlaup
• What are the factors that influence a lava flow's speed? (4)

  - viscosity

  - temperature

  - silica content

  - incline of the volcanos slope
• What are the gases released during an eruption and what hazards do they bring? (4)

  - water vapour (leads to heavy rainfall)

  - sulphur dioxide (these particles reflect sunlight back into space and cool the earth. It can also mix with water to form 'acid rain')

  - fluorine gas (can be poisonous in high concentrations and can contaminate farmland)

  - carbon dioxide (tiny amounts can be emitted during eruptions)
• What are pyroclastic flows made of and how are they dangerous?

  They are a dense mixture of superheated tephra and poisonous gases that move down the volcano when erupted. Anything in the path of one is likely to be destroyed, either by impact, burying or burning.

  They also leave behind thick layers of volcanic deposits
• What is a jokulhaup and what are its dangers?

  It is a flood of water from the melting of an ice cap or glacier. This happens when a volcano erupts underneath the ice and melts it so that a lake is formed. Once the water has sufficient volume, it bursts out and will wash away anything in its path and can change the route of river channels
• What is the definition of an event?

  the group name for such occurrences as earthquakes, volcanoes and tsunamis
• What is the definition of a hazard?

  a naturally occurring process or event which has the potential to threaten both life and property
• What is the definition of a disaster?

  a major natural hazard that causes significant social, environmental and economic damage
• When does a hazard become a disaster?

  When a natural hazard strikes a vulnerable population that can't cope using its own resources
• What is the definition of vulnerability?

  The ability to anticipate, cope with, resist and recover from a natural hazard
• What is the hazard-risk formula? - Dreggs model

  Risk (R) = [Hazard (H) x Vulnerability (V)] / Capacity to cope (C)
• What are the ways governance can affect vulnerability? (7)

  - the enforcement of building codes and regulations, making the buildings safer for those living there

  - the quality of infrastructure, such as transport and power supply

  - disaster preparedness plans influences how quickly and efficiently a country can respond

  - the efficiency of emergency services

  - the quality of communication systems allowing people to know about disasters in advance

  - the level of corruption of the government

  - the levels of public education about what to do
• What are the ways physical and environmental conditions can affect vulnerability? (3)

  - rapid urbanisation creates a need for more housing which can lead to poor quality buildings

  - areas with high population density have worse building quality

  - the accessibility of an area affects how easily and quickly aid can arrive
• What are the ways different economic and social conditions affect vulnerability? (5)

  - the level of wealth influences people's ability to protect themselves and recover after

  - people without access to education may be less aware of the risks involved and how to protect themselves

  - poor-quality housing is less able to withstand the impacts of a disaster

  - communities with poor health care suffer more disease

  - a lack of income opportunities means people can't buy the resources they need
• Describe what the Pressure and Release (PAR) model looks like

  it consists of the three progressions of vulnerability:

  - root causes

  - dynamic pressures

  - unsafe conditions

  
  

  It combines these with the natural hazards to get a disaster
• What are some examples of Root Causes in PAR model? (3)

  - having limited access to power, resources and basic structures
• What are some examples of Dynamic Pressures in PAR model? (7)

  lack of:

  - training/ awareness

  - local investments in infrastructure projects

  - ethical standards of life

  
  

  
  

  - having a rapid growing population

  - rapid urbanisation

  - debt repayment schedules

  - deforestation
• What are some examples of Unsafe Conditions in PAR model? (5)

  physical:

  - dangerous locations

  - unprotected buildings and infrastructure

  
  

  economy:

  - low income levels

  
  

  society:

  - lack of local institutions

  
  

  public:

  - lack of preparedness
• Give the general facts about the Armenian Earthquake in 1988 (6)

  - happened on 7th December 1988

  - Northern Armenia is located between Turkey and Azerbaijan

  - it happened at 11.41 am local time

  - it was a 6.9 on the richter scale, with aftershocks at around 5.0

  - approx. 25,000 died

  - approx. 31,000 injured
• Give some general facts about the San Francisco earthquake 1989 (7)

  - happened on 17th October 1989

  - occurred in San Francisco Bay Area, in California

  - it happened at 5.04 pm local time, lasting 15 seconds

  - it lies on the San Andreas Fault Line

  - it was a 6.9 on the Richter scale

  - 63 killed

  - 3757 injured
• What are some facts about Armenia that affected its Vulnerability in the 1988 earthquake? (3)

  - the area had mainly high rise buildings so were more susceptible to collapsing under earthquakes

  - the city of Leninakan was badly affected because of the sedimentary rock below it meaning the ground was weaker and didn't resist the earthquakes easily.

  - the building's concrete was weak and the infrastructures were poorly secured. Many criminal charges were given to those responsible for the major design flaws.
• What are some facts about Armenia that affected its Capacity to Cope in the 1988 earthquake? (5)

  - they received around $500 million in donations

  - Armenia was still struggling in the USSR, meaning there were restrictions about what aid was allowed in the area.

  - Most of their fire stations were destroyed due to weak infrastructure

  - Most hospitals were destroyed, killing 2/3 of their doctors, meaning they weren't able to deal with the sick or injured

  - they were under the control of the Soviet Union, meaning it made it hard to gain aid from USA
• What are some facts about USA that affected San Francisco's Vulnerability in the 1989 earthquake? (4)

  - much of the city is built on sand and other non-compacted soil, which lead to liquefaction and caused more devastation.

  - the houses in SF are the oldest in the West and so this posed a problem as they were less earthquake resistant.

  - 75% of the houses there are rented so they are covered by rent control which led to many of the houses being poorly maintained.

  - the bridge fell down in the earthquake, even though it was meant to be resistant
• What are some facts about USA that affected San Francisco's Capacity to Cope in the 1989 earthquake? (6)

  - the repair work came to $6 billion for building and property damage.

  - 1.4 million people lost power, knocking out radio and television stations which limited the amount of communication

  - 12,000 became homeless

  - the earthquake caused a major gas leak and took out the major source of water

  - there was a rescue effort from the emergency services which allowed trapped people to be found, minimising the death rate

  - as the bridge collapsed, many roads were blocked and transport links were reduced which affected getting aid to the area as many of the services were trapped on the other side of the bridge
• Give some general facts about the Haiti earthquake in 2010 (7)

  - Happened on the 12th January 2010

  - it was nearly 5pm (local time)

  - It was caused by the Caribbean and North American transform plate boundary where the plates move 20mm a year.

  - it was a 7.0 on the Richter Scale

  - there was over 316,000 deaths

  - estimated over 300,000 injuries

  - it did $7.8 billion in damage
• What were some of the factors of Haiti that affected their Vulnerability in the 2010 earthquake? (5)

  - Haiti had a lack of early warning systems so fewer people were able to evacuate

  - the infrastructure was inadequate so more houses and buildings were damaged easier

  - haiti is the poorest country in the western hemisphere which made it more economically vulnerable

  - 38% of their population were under 14 years old, making them more vulnerable

  - 80% of the population lived below poverty line, meaning they had little money to spend on solid houses, emergency supplies etc.
• What are some factors of Haiti that affected their Capacity to cope in the 2010 earthquake? (4)

  - most lived in poverty so were less able to cope with the earthquake

  - a lack of communication meant it was harder for aid and made rescue more difficult

  - $3.5 billion was given as aid as of 2013

  - the country took a while to start rescue and aid, due to aftershocks but also because governmental buildings and such were damaged.
• Give some general facts about the earthquake in Christchurch, NZ in 2010 (7)

  - happened on the 4th Sept 2010

  - occurred at nearly 1pm local time

  - It was caused by right-lateral movement a regional strike-slip fault in the western section of the Canterbury plains.

  - it was between 7.0 and 7.1 on the Richter scale

  - there was over 11,000 aftershocks

  - around 185 people died

  - between 1500-2000 injured
• What are some factors of NZ that affected Christchurch's vulnerability in the 2010 earthquake? (4)

  - the cathedral and many older brick buildings were known to be more vulnerable and some structures were weakened by the earthquake

  - the damage was more severe due to the city resting on damp sediments

  - The city is very vulnerable to liquefaction as it is built on a sedimentary plain

  - The earthquake struck while streets were busy with lunchtime shoppers, meaning more people were likely to be hit by flying debris or be trapped in a collapsing building
• What are some factors about NZ that affected Christchurch's Capacity to cope in the 2010 earthquake? (4)

  - almost 8,000 of the areas houses were "red zoned", meaning it was unlikely they could be rebuilt on the same land.

  - Japan sent 70 rescuers equipped with fibre optic cameras and sound detectors, as well as sniffer dogs trainer to find people in the rubble.

  - rescuers has tents, portable toilets, food and medical kits for the homeless.

  - many countries sent rescuers and teams to help search and provide emergency assistance.
• What is a hazard profile?

  A diagram that shows the main characteristics of different types of tectonic hazard.
• What does the term "speed of onset" mean on a hazard profile?

  how quickly it happens (such as earthquakes being quicker than tsunamis)