Alaska Flashcards
Trans Alaska Pipeline
Transports oil from Prudhoe Bay to Valdez for shipping
75% passes through permafrost region
In areas of continuous permafrost the pipe is carried above ground on vertical support members (VSM)
why was the government so keen to extract oil?
40% of their oil comes from imports
Want to be as domestically sufficient as possible - ENERGY SECURITY
16 billion barrels estimated in area 1002
6 extracted using current technology and can make use of the Alyeska Pipeline
What is the urban heat island effect?
a white object reflects all wavelengths of light.
Dark objects absorb heat from the sun.
Heating systems and cooking facilities along with transportation emit extra heat into the environment
How does the oil industry contribute to the urban heat island effect in Barrow?
Temps on average 2.2 degrees higher
Poorly insulated buildings
drilling and pumping produce more heat
The city’s infrastructure, particularly water, sanitation, power and road stability, is endangered.
The shoreline is rapidly eroding and has been encroaching on buildings for decades.
prudhoe bay
Alaska has a huge oilfields
including Prudhoe Bay on the North coast, with proven reserves of about 3000 million barrels.
1300 km Alyeska pipeline runs from Prudhoe Bay
transports oil up to 1.4million barrels per day
need for oil
In 2014 the USA consumed 6.95 billion barrels of oil products
Prior to 2013 there’d been falling consumption during the global economic recession
2013 demand had risen
reserves
exploration of oil felids in Alaska has been permitted by the government
Extracting oil from Area 1002 means there will be increased employment opportunities and the existing Alyeska pipeline can be used
Gravel pads
Gravel extracted from stream/ river beds and used as an insulating base layer for construction
Loss of gravel alters the rate at which gravel is transported and deposited downstream.
Hydrological processes also affected - affects the equilibrium between
A report into gravel extraction from a glacial outwash aquifer near Palmer found that ground water levels fell by more than a metre in an area over 2km from the extraction site
The impact on the periglacial landscape system
gravel pads
energy flow - drilling or extraction/ transportation
Energy flows affected by drilling
release and burning gas during drilling
Some gases are burnt in a process called flaring, releasing CO2 into atmosphere
Methane is vented without
Both CO2 and methane are significant greenhouse gases and contribute to an enhanced greenhouse effect
higher levels of terrestrial radiation being trapped in the lower atmosphere, raising temperatures
energy flow affected by extraction and transportation processes
heat from the extraction, transportation processes and from associated infrastructure
UHI in Barrow mean temperatures on average 2.2 degreesC higher than surrounding rural areas
6 degreesC was measured on a calm day
Heat from domestic heating systems in poorly insulated buildings, major contributor to the heat island effect
Strong correlation was found between temp differences and oil production rates in the nearby oilfield
impact on landforms
solifluction lobes
thermokarst
solifluction lobes
Permafrost experiences less variation in temp than the active layer because it is not directly exposed
The heat released by buildings and infrastructure can lead to the thawing of permafrost and longer period of melting of the active layer
If building constructed on ground = heat may be transferred through the floor to the ground
melting the permafrost = subsidence and increase the mobility of the active layer, allowing mass movement = solifluction
The downslope movement of the thawed active layer results in the formation of solifluction lobes, lounges of debris, at the base of slopes when the moving material loses energy on lower gradient
thermokarst
depressions due to the thawing of ground ice
extensive areas of hummocky ground interspersed with waterlogged hollows
Depressions fill with water to form shallow thaw lakes - less than 5m deep and 1-2 km wide
Larger scale = alases are flat-floored, steep-sided depressions ranging from 5 to 50m in depth and 100m to 15km in length
Where several alases combine, alas valleys may form - can be many tens of kilometres in length.
The removal of vegetation for resource extraction or construction purposes decreases the insulation of ground
Leading to thawing to greater depths, creating a thicker active layer and producing much deeper and more extensive subsidence
On the north slope of Alaska, research into thermokarst depressions found subsidence rates averaging 3-4cm per year - max. Of 12cm/year
Permafrost 300-600m deep and the active layer 30-80 cm thick
