Hazards Flashcards
how much money does Japan invest in earthquake resistant buildings and drills due to high hazard frequency
$7 billion disaster prevention budget
Constructive plate margin case studies
-Mid Atlantic Ridge = 16,000km long, contains some of the youngest rock, north american and eurasian plate move away
-Great African Rift Valley= 5,000km 50km wide, on contnental constructive, african plate is in the process of splitting into two; somali and numbian plates = also creating Mt. Kilimanjaro
destructive plate boundary
-Mariana ocean trench 10km deep caused by subducting pacific plate
-Japan island arc approx 100 volcanoes due to subducting pacific plate
-Himalayas fold mountains due to collision of Indian and Eurasian plate
Conservative plate boundary
-San Andreas Fault
California
-the pacific plate and north american plate are in contact moving in the same direction
-pacific plate is moving faster = 6km per year, N american is moving at 1km per year
-as Pacific plate is moving faster = illusion that they are moving in opposite direction = relative motion is opposite
How do intra-plate volcanoes occur?
-at hotspots = volcanoes located over stationary plumes in the middle of the plates, as thee plume = island chain is formed e.g Hawaii with 8 islands and 15 volcanoes
give examples of human induced earthquakes
- mineshaft collapse = 1989 Bristol 2.9 richter scale
2.Building collapse = NYC twin tower 2.0 richter scale
3.nuclear testing= N.Korea 6.3 Richter scale - Reservoir construction= 3 Gorges Dam China = 5.1 Richter scale, mass of water causes downwarpping of the crust = RIS reservoir induced siesmicity
5.Fracking = Texas 4.0 richter scale
Mt. St Helens eruption
1980:
-pyroclastic flows moved at 300mph
-massive landslide with debris flow between 112-193km/h
-subsequent vertical explosion sent volcanic ashes and gases 18km up into the air =about 540 million tons of ash deriving from eruption
what kind of economy is Montserrat, Caribbean vs Iceland
Iceland= developed country with strong economy, 31.02 billion USD GDP
Montserrat= LICs, one of the less economically successful of all Caribbean islands
the event of Montserrat eruption human vs physical factors:
physical:
-volcano in dormancy for over 300 years= unexpected eruption in 1995
-Montserrat lies on a destructive plate boundary, Atlantic plate is subducted under carribean plate= large amount of magma and andesitic lava
-in 1997 dome of volcano collapsed sending 5 million m3 hot rock and gases down the side = pyroclastic flows killed 19 people
human:
-LIC, GDP US$ $63 million
-most people work in primary sector/ agriculture = low economic levels
-corrupt misuse of aid money e.g $40 million from the UK
what were the impacts of Montserrat erruption
social:
-19 people died
-hundreds lost their homes
-fires destroyed many buildings e.g local government offices, police head quarters and petrol stations
-population declined= 8,000 of 12,000 inhabitant left the eruption and many haven’t returned
economic:
-total value in loss of people’s homes and investment = around $1 billion
-over 20 villages and 2/3 of homes on island were destroyed by pyroclastic flows
-businesses destroyed, tourists stayed away
-schools, hospitals destroyed
Environmental:
-large areas covered with volcanic material- capirtal city plymouth was buried under 12m of mud and ash
-vegetation and farmland were destroyed
-volcanic ash from the eruption has improved soil fertility
what were the short and long term responses and management
short term responses:
-installed monitoring systems after initial phase one= GPS measure the bulging of island, gas spectrometers detect sulphur dioxide and seismometers to detect earthquakes
-people evacuated from the south to the underdeveloped north
-temporary shelters and infrastructure
-$17 million in aid donated from UK
long-term:
-maintenance of exclusion zones and 3 year development plan to fund rebuilding
-$41 million in long term aid to develop the North
-new hospital has been adapted from a school in the north
-ports and airports eventually reopened
-tourism = 15% of GDP
the event of E15 Iceland 2010
human vs physical factors
Physical:
-conservative plate boundary between north american and eurasian plate= basaltic fluid lava
-eruption lasting 39 days
-10km high ash plumes, containing sulphur
-some earthquakes
flooding from jokullhaup river due to the melting of the glaciers
human
-HIC and GDP $31 billion = good management e.g diggers in position to dam and block rivers and lava, equipment worth half a billion invested in lava cooling equipment
what were the impacts of E15
social:
-700 people evacuated due to flooding from melted glacier
-ash contaminated drinking water supplies
-respiratory issues due to ash
-cancelled flights left many stranded
economic:
-stopped 10,000 jet engines just in europe
-horticulture lost $3 million a day
-airline industry lost $130 million a day
-ash made soil more fertile= more crops
environmental:
-long-term effects on soil and water quality
-river became 100x its normal capacity
-fluoride deposits= contaminated crops
-rivers silted with ash
what were the responses of E15
short-term:
-700 locals evacuated
-exclusion zones created
-emergency services and airspace closure =100,000 European flights cancelled
long-term
-monitoring and research improved
-icelandic government rebuilt river banks higher than before
-european union developed intergrated strucutre for air traffic management
-economic support for affected famers and businesses
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how was iceland and montserrat prepared for the volcanoes
iceland;
-diggers were in position to dam rivers and texts were sent to locals with a 30 minute warning
montserrat
-no emergency plans and after 1995 warning signs, no one evacuated as no one thought it was long-term
