Earthquakes And Volcanoes Flashcards
Global distribution of earthquakes
- occur on narrow belts
- follow all types of plate margin
- near volcanoes
- occur on land and sea
Global distribution of volcanoes
- occur in long, narrow belts
- mostly found at destructive margins, especially around Pacific Ocean- “The Pacific ring of fire”
- coincide with constructive margins
- sometimes found away from margins- hotspots
- found at both land and sea
- less frequent than earthquakes
general background information of chitin
- town of chitin is located on the jagged coastline of Chile, and has a population of 4500
- chaiten is a coastal town and is located 10km south west of the volcano
- on 2nd May 2008, volcano was thought to be dormant but erupted for the first time in 9000 years
- chaiten is a composite volcano
causes of the chaiten eruption
- converging convection current in mantle causes the Nazca plate to move in an easterly direction and collide with the westerly moving South American plate - destructive plate boundary
short term impacts of chiaten eruption (social, environmental and economic)
SOCIAL:
- by 8th may, chilean navy had evacuated the majority of 4500 residents of chiaten. this evacuation by sea led to death of one elderly man
- peoples skin, eyes and lungs were irritated by the ash- advised to wear face masks and long sleeved clothes
- a lahar flowed down the valley of rio blanco and destroyed the building in the southern part of chiaten, leaving behind a layer of ash 1 meter thick
- chilean government didn’t let people return to chiaten, and built them a new town further from the volcano in Santa Barbara- this led to conflict as some wanted to return home
ENVIRONMENTAL
- sulphur in the ash polluted the water which people drank- had to be provided with bottled water
- a 10km squared forest area on northern slopes of volcano was destroyed by a pyroclastic flow
ECONOMIC
- ash contaminated grassland that was used to graze livestock- animals died- farmers had decreased income
- chiaten is a major concern to airline industry; volcanoes eruption reached 15km high (twice a jets cruising altitude). airports in Chile, Argentina and Uruguay were forced to cancel flights
long term impacts of the chiaten eruption
- residents evacuated lost their homes and all their possessions- found it difficult to find work and received little compensation from government- difficult to support families
- in 2011 only 400 people lived in chiaten and government had still not reconnected the electricity and water supply to the town.
- people couldn’t return home
why do people live in Iceland despite it being affected by volcanic eruptions?
GEOTHERMAL ENERGY- generates cheap electricity used in the manufacturing of aluminium and paper- provides jobs for people
- geothermal water heats peoples homes cheaply+ sustainably
- used in heated greenhouses to grow fruit and vegetables for consumption of locals
TOURISM- travel to Iceland land to see landforms such as; the famous Strokkur geysers at geyser and to swim in outdoor thermal pools such as the blue lagoon- provides jobs for locals.
MINING- extraction of minerals such as Pumice mined from around Hekla is used to produce building blocks and basalt is crushed to produce cement- used for building industry
BREWING/BAKING- unique microorganisms and enzymes in hot springs are used in brewing and baking industries
FARMING- livestock farming occurs in southern coastal plains of Iceland because volcanic ash has been weather to produce fertile soils where grass grows
- seas around Iceland have large fish stocks which support the large fishing industry which employs many people
why do earthquakes affect LICs more than in HICs?
- poor building design- likely to collapse - more casualties - block roads more, so less travel space for search and rescue teams
- less organised search and rescue teams due to poorly equipped services
- less education on evacuation/safety, so don’t know what to do
- hospitals poorly equipped, can’t cope with casualties
- reliant on international aid which takes time to arrive
causes / background info of Christchurch earthquake in New Zealand
- occurred on 22 February 2011
- 6.3 magnitude
- focus was very shallow at 4.99 kilometres deep
- happened on a conservative plate boundary between the Pacific plate and the Australian plate, where a slippage occurred
- before: on 4th September 2010, Canterbury earthquake occurred here, with a higher magnitude but didn’t cause as much damage as focus was deeper and epicentre wasn’t as close to Christchurch town
impacts of Christchurch earthquake in New Zealand
INFRASTRUCTURE:
- Schools were closed for two weeks due to the damage.
- Over 50 per cent of the city’s buildings were damaged.
- The city’s cathedral spire collapsed.
- Train and bus services were severely disrupted.
- Water and sewage pipes were damaged.
SOCIAL/ECONOMIC:
- 181 people were killed.
- 2,000 people injured.
- Damaged sewage pipes contaminated water supplies which increased risk of disease.
- Businesses were closed for a long time.
- Christchurch could not host five Rugby World Cup matches.
Why do people live in areas where earthquakes occur?
- cant afford to move
- have lived there all their lives
- lack of space elsewhere
- work/ education available in the area
- friends/ family in the area
- unaware of risk
