Weather GW 3 And Plate Tectonics 🔴🔴 WE NEED WEATHER GW 1-2 Flashcards
What are cyclones and where
Weather systems that dev over warm oceans in the tropics
Lat. 8-15• N and S of equator : requires warm waters in presence of coriolis effect
Warm waters: above 26.5•c
Move westward
Recall the pic of the cyclone cross section
Eye wall! Sun bands! Wind up! Rain!!
Cyclones: storm surges
Sudden rise of sea level : water is piled up against coastline beyond normal conditions. Causes property damage and massive flooding thus damage and death.
2008 hurricane ike caused storm surge between 4-6 metres in Texas. Est property damage was 24.9 bil usd
Cyclones: Strong winds
Strong force of winds damage or destroy infrastructure and injure ppl
Causes loose debris to fly and hit ppl and buildings
Large impact area
1992 hurricane Andrew had wind speeds up to 117 km per hour - widespread damage to Bahamas and parts of USA. Damage to infra and disrupted power supply - 150k homes w/o electricity
Cyclones: torrential rains
Large amt of rainfall that result in flooding inland : sudden water adds to rivers and streams- overflow
2003 hurricane Isabel flooded rivers in Virginia, Maryland, Delaware, and Washington DC in USA. Flood area abt 120 times sg, damages of >US 2.23 bil
Physical impacts of cyclones (2)
Damage to infrastructure : storm surges- huge waves crash down, flooding, damage
Disruption of comms : electrical wires topple, Comm buildings destroyed - ppl cannot go to work- econ affected // - ppl cannot seek help- death and injuries
2009 typhoon Ketsuna damaged road network in Philippines, Cambodia and Laos. 80% of health centres in Manila (Philippines) was destroyed. Difficult to distribute meds and food
Economic impact of cyclones (2)
Cost to repair infrastructure: storm surges- lots of buildings destroyed - costly repairs- less $ to dev other parts of food
Hurricane Katrina 2005 hit East Coast of USA cost 81 bil usd, large part was repair of 200k homes
Loss of income due to destroyed crops: farmlands destroyed- no crops to sell- loss of income, food shortage
Cyclone Yasu hit North Queensland Australia 2012, 75% banana crop (US350 mil) destroyed
Social impacts of cyclones 3
Disruption to water supply : water pipes burst/ contaminated
2009 cyclone alia hit West Bengal India caused cholera outbreak 1000 infected 14 deaths
Spread of diseases : flooding- breeding ground for mosquitoes (mosquito borne diseases)
Hurricane Mitch 1998, cases of dengue in Guatemala and Nicaragua due to flooding.
Displacement of ppl from homes : flooding- homes destroyed - homelessness
Hurricane Katrina struck New Orleans USA in 2005 thousands of ppl lost homes
Responses and measures to cyclones: emergency action
Emergency action- weather warnings and advisories :
evac to cyclone proof shelters, reduce death
eg. India and
Bangladesh - lower death during 2009 Aila due to network of 2500 shelters and sms warning
Responses and measures for cyclones : prediction and warning
Establishes pattern of occurrence and severity of damage: by analysing pattern, predict
Meteorologists studying 2005 Katrina warned for evacuation before 2008 Ike moved into Texas
L: records only indicate frequency, no accurate details
Response and measures for cyclones: regulate land use
Regulates land use - flood/coastal plain management
Practiced in hurricane prone areas eg. New Orleans and coastal japan and Taiwan - vulnerable to storm surges
L: authorities need to enforce the rules- req time and manpower. Coastal residents often reluctant to move out- costly to buy back land
Response and measures to cyclones: Reducing infrastructure vulnerability
Buildings designed to resistant against wind and water damage
- galvanised steel hurricane tiles on roof: not blown off
- secondary water resistant layer on roof, prevents leaking
Houses with such in Florida USA survived 2005 Wilma
Earthquake preparedness measure: infrastructure
Advanced engineering can withstand earthquake vibrations - use of steel and reinforced concrete, damping devices such as shock absorbers and heavy wide bases
Taipei 101 has a damping device: reduce swaying by up to 40%
Less destruction , less buildings collapse , less econ and lives lost
Expensive, developing countries cannot afford
Earthquake preparedness measure: emergency drills
Practice of what to do during earthquake
Japan drills - 1st September to commemorate disaster prevention day
Ppl know what to do
Ppl may panic and forget
Earthquake preparedness measure: earthquake and tsunami monitoring systems
Earthquakes monitored by study of history of when and where, est of frequency and magnitude at fault line: prediction
Earthquake motion data gathered from observation stations in Japan
Tsunami: network of pressure sensors and seismographs, deep ocean tsunami detectors located in Hawaii
Allows ppl to evac, less loss of lives
L: only a general indication, not precise. Expensive to install and use, many not provide sufficient time, false warnings
Earthquake short term responses : search and rescue
Ppl trapped in collapsed buildings are located and freed
2011, Tohoku Japan : heat sensors and sniffer dogs were deployed
Many ppl rescued, reducing death rate
Rescue ppl have 72 hours (3 days) to find survivors
Earthquake short term responses: emergency food and medical supplies
Injured treated, provide clean drinking water - prevent dehydration and disease spread
2002 Afyon, turkey - Turkish red crescent society delivered 20k rents 50k blankets and 3k heaters
Reduce loss of lives, help injured, reduce spread of diseases
Meds and food may not be sufficient : social unrest eg. 2010 Haiti, looting and fighting broke out
Long term responses earthquake: rebuilding of infrastructure
Rebuilt and improved, dev structure building codes, endeared higher safety level than before
1995 Kobe Japan, billions spent to dev tech to build more resistant buildings
Less damage to infrastructure, less cost of rebuilding, less loss of lives
Reinforced buildings not necessarily prot against tsunamis (add. prot in form of coastal structure)
Eg. Many buildings in Chile resistant, but coastal area tsunami damage in 2010
Long term responses earthquakes: provision of healthcare
Health options such as long term counselling
A year after 2011 Christchurch NZ, significant depression and anxiety amongst affected population: more health workers in area
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Improving health options eg. Restoring resilience
can be challenging
Why do tectonic plates move?
Convection currents
1. Mantle mat heated by core
2. Expands rises spreads out
3. Plates dragged along
4. Mantle mat sinks pulling plates along
5. Heats up and repeats
Slab pull force
1. Dense sinking oceanic plates at subduction zones pull rest of plate
2. Drives downward motion of CC
3. Mantle mat away from sub zone drives rising CC
Internal structure of earth (the pie)
Crust
- basalt, granite rocks
- few km to >10km thick
Mantle
- mostly solid rock : flows under ^temp and ^pressure
- 2900km thick
- 800-3k deg celcius
Core
Mostly iron and nickel
Liquid outer and solid inner
Temps of 3000-5000
