Earthquakes: Izmit

Conservative plate boundaries 3.1
Izmit, Anotolian strike-slip fault systems 3.12

Izmit is a bay in north west Turkey situated on the North Anotolian Fault Zone. This zone is the result of stress on the Anotolian micro plate which consists primarily of the the land mass Turkey. The plate is being squeezed and forced West at the rate of an inch per year by the surrounding African, Eurasian and Arabian plates which combine to create several conservative faults as all of the plates are moving west at different speeds, similar to California. Coastal areas in Turkey therefore become very hazardous as there is a high risk of earthquakes due to multiple Anotolian faults.
In 1999 one such earthquake struck in Izmit as the result of a shift in the strike-slip North Anotolian Fault Zone between the Anotolian plate and the Eurasian Plate which killed up to 45,000 people in non-official reports. The epicentre was 17km deep and created a quake measuring 7.6 on the richter scale. As a result of the shift a 150km rupture was also created traveling East from the quake's epicentre in a step like formation that measured up to 5m high. Overall the plate boundary has proved itself very dangerous but there are other factors involved in the creation of this hazard.

One example is the physical location of the earthquake and many other potential risk zones. As Anotolian faults run across the coast of Turkey there are risks of secondary hazards. In the 1999 Izmit quake the coastal rupture created a tsunami 3metres in height which hit the populated bay of Izmit, amplifying the hazard.
Furthermore coastal locations are also heavily populated as they are attractive for resources such as fishing and transportation. As shown in Deggs model the 1999 quake could not be a hazard without its proximity to populated towns such as Izmit and Istanbul which were both affected by the earthquake.
There are also geological factors to be considered. Unlike Loma Prieta this earthquake struck in north west Turkey, an area of soft rock formed mainly from sea soil. Therefore the land was less stable and more vulnerable to movement. As a result more buildings and infrastructure collapsed creating more of a hazard to life and the economy.
As shown in the case of the Izmit 1999 earthquake the plate boundary is important but other factors are also influencial .... [relate back to quaestion here in conclusion and throughout]

[Information found on geography.com and cross referenced with several academic blog pages. Information about types of plate boundaries found in geography A2 edexcel textbook]

Unit 4 Revision Hazards

Quick Case Study.

Sichuan Earthquake 2008
In 2008 an earthquake hit Sichuan province with an epicentre north of the city Chengdu. The magnitude of the quake measured 7.8 on the Richter scale and killed over 67,000 people. The epicentre of the quake was 19kms deep and lasted less than three minutes there were as many as 100 major aftershocks recorded over magnitude 5. As a result a rupture in the land formed along the fault stretching around 250kms in a north east direction from the epicentre and displaced the land in a step like split up to 9ms high. The quake was felt in several surrounding countries such as Russia and India but the area of destruction was mostly limmited to the Chinese province.

Sichuan province sits on a series of thrust faults created under immense pressure from the divergence of the Indian and Eurasion plate over the past 50m years. This has created folds (high relief) and cracks (mid-margin faults) in the crust. Even though the Longmen Shan fault was the cause of this 2008 earthquake, the rupture released such a lot of energy that it continued along the Fold and Thrust Belt (FTB) forming a two pronged rupture and destruction over a wider ariel extent. The reason why stress builds at this fault is because of the slowing of the Eurasian plate. The Eurasian plate is pressured into a north west direction but between the Sichuan basin and mountains the movement slows by 4mm per year.

The potential causes of the Sichuan earthquake as a hazard are:

• Lack of sufficicient mapping/ building regulations
• Dense population of 15m with close proximity to hazard
• High magnitude earthquake over a wide ariel extent
• Low GDP only 25% of global average ($8,500) vulnerable
• High relief limits accesss and poses an additional risk of land slides
• Severe aftershocks an extension of the hazard
• Last significant quake over 70years ago, low perception of the risk

Shell's Justification of Oil Sand Mining

http://www.shell.ca/home/content/can-en/aboutshell/our_business_tpkg/business_in_canada/upstream/oil_sands/quest/

Iceland Unit Four Case Study

Iceland

Q1 Tectonics

Volcanic islands formed on a constructive plate margin.

Iceland is one of the most volcanically active countries in the world with 39 eruptions occurring in or around Iceland in the 20^th century. Around one third of all basaltic eruptions in recorded history were found in Iceland.

Iceland is situated along the mid-Atlantic ridge where the Eurasian and North American plates are moving apart.
Examples:

·         A fissure in Katla in 984 erupted to make the largest basaltic eruption ever seen.

·         Laki in 1783 which was only second in size to Katla.

There have also been several eruptions beneath glaciers which have led to glacier bursts. The most recent was E15 in 2010.

E15 ß is a mountain glacier where the glacier (over 100km²) covers the caldera of the volcano. Explosions can also have secondary effects on outlet glaciers (connected glaciers) and mountains as the power of the eruptions often lead to landslides, in 1967 there was a massive landslide on the Steinholtsjökull glacial tongue. ß Earthquakes are likely due to pressure of ice, violent eruptions even though they are basaltic. Massive ash clouds and water jets are the most common result of eruption due to the glacier above the vent of E15.

Q2 Landscape

An island country, the main island is just south of the Arctic Circle and the country itself is on the boundary between the North Atlantic and Arctic oceans.

E15 ß The summit is elevated 1,666ms above sea level and the Caldera is filled by a glacier which is over 100km² in size. The ash cloud created by E15 that covered Europe in 2010 was the largest disruption to air travel since the Second World War. The eruption in April ejected around 250million cubic metres.
The Mid-Atlantic Ridge is part of the longest mountain range in the world as it is a part of every ocean stretching over 65,00kms. The ridge is a spreading centre (which means the sea floor expands with lava rising to the surface) and grows at a rate of around 2.5cms per year. The ridge was also central in the initial breakup of Pangaea.
Mountainous hilly landscapes with long slow slopes and peaks like waves, land may be suppressed by weight of glaciers. Land is rich in minerals and is therefore a biodiversity hotspot; basaltic lava is easily eroded away by glaciers. Fissures are common (e.g. Laki not a volcanic eruption but fissures either side) create wide flat plains with a stair like structure.

Q3 People

500 people had to be evacuated as a result of the 2010 eruption but the population is so low that even being a tectonic hotspot, there is little chance of disaster. Laki’s eruption killed 50% of all livestock and 25% of the human population.

However, globally Iceland has been known to have a bigger impact. The 2010 eruption caused the largest disruption in air travel since the Second World War.

Laki’s eruption also may have resulted in a global temperature drop due to sulphur emissions. There was also estimated to be 6million deaths as a result worldwide. There were also crop failures in Europe and droughts in India as a result of the air pollution.

Q4 Management

There is little that can be done to manage the eruptions but seismic activity is recorded in order to predict any future eruptions. There are also evacuation measures in place. Usually the European political systems are responsible for this as being closer to mainland Europe than mainland North America they are often associated together.

 

http://en.wikipedia.org/wiki/Iceland_hotspot

http://www.platetectonics.com/oceanfloors/iceland.asp

http://www.ouramazingplanet.com/3074-iceland-tectonic-plates-meet.html

The Great African Rift Valley A2 unit four case study

The East African Rift Valley

Q1 Tectonics

The Great African Rift Valley is the south branch of the Afar Triangle, the only one remaining which has not yet been filled by the sea. This is therefore an example of continental rifting.

The rift itself was formed by a combination of two key factors:

·         The constructive/divergent plates: African and Arabian.

·         And the magma plume beneath the plates.

The plume pushed up the land creating bulges and cracks allowing flood basalts to rise through fissures and add to the gradient and create long mountain ranges.

As a result of the divergent plates a small section of land in between these plates breaks away and sinks leaving faults which are filled and covered by lava (flood basalts)

Horsts and Grabens are therefore formed (raised land and depressed land)

ß Secondary processes:

·         Shield volcanoes formed in depressions (Grabens) as a result of weak thin crust. Magma pushes easily to the surface, pure, easily eroded shield shaped structures.

·         Composite volcanoes found on raised areas (Horsts) as a result of folding, faults form in the thicker crust, magma pushes to the surface but faces obstruction: higher pressure, explosive pyroclastic flows. ß Steep cone shapes.

·         As a result of volcanoes and faults there is also a minor risk of seismic activity in the area, mostly attached to erupting composite volcanoes.

Examples for each process named in the landscape section below.

Information found from Geology.com and the article ‘East Africa’s Great Rift Valley: A complex rift system.’

Q2 Landscapes

 The Rift Valley stretches over approximately 5000km from Syria to Mozambique. It is a massive horst and graben structure with steep sided sloping mountains surrounding low lying valleys that host lakes, deserts and shield volcanoes. 

The width of the rift varies between 30-100kms and the depth also varies from a few hundred to a few thousand metres.

The rift is 35million years old and is still growing meaning that eventually East Africa including the horn of Africa: Ethiopia, Somalia and Eritrea will break away and form its own continent (the rift being filled by the sea.

Many parts of the rift are already filled by lakes: some freshwater and some salinized. Lake Tanganyika is the 2^nd deepest lake in the world.

Secondary landforms created as a result of the rift include Mt Kenya 5,200m extinct and Mt Kilimanjaro 5,900m dormant, the two tallest mountains (composite volcanoes) in Africa.

Erta Ale is also a volcano in the Rift Valley but instead is a shield volcano that continuously erupts in the Afar depression. Being wide with soft slopes it is only 613m high.

Q3 People

5 scientists were executed on by the Afar Tribe when trying to visit the Erta Ale in January 2012. The tribes are uneducated and difficult to reach, meaning they are vulnerable to tectonic activity.

Human Uses/Benefits:

·         Tourist attraction i.e. beautiful scenery e.g. lakes, mountains, escarpments etc.

·         Lakes in the rift valley provide fish.

·         Lakes in the rift valley provide water for domestic and industrial use and irrigation for agriculture.

·         Rain shadow areas /areas with low rainfall provide pasture for grazing.

·         Lakes are used for navigation.

·         There is forestry on the slopes, so source of timber.

·         Gentle slopes are used for arable farming and settlement.

·         Wildlife conservation

·         Salt-water lakes are used for mining.

·         Production of geothermal electricity from underground.

Challenges:

·         Poor means of transport and communications leaving rural areas without access to services.

·         Shortage of water due to high temperatures, geothermal activity basins.

·         Earth quakes (tremors)

·         Little rainfall /drought in the rain shadows areas.

·         Volcanic eruptions, which destroy property and lives.

·         Poor soils in areas of frequent eruptions.

·         Flooding in depressions.

·         Salty lakes because of high temperatures/high evaporation.

The rift valley lakes are essential to the African economy. Lake Victoria is responsible for a large percentage of the Nile discharge making arid land habitable. Being dependent on primary agricultural and fishing industries, the continent is heavily reliant on the great rift lakes.

Q4 Management

The main management strategies involved in the rift valley are environmental or conservation projects. The WWF is example of this, attempting to protect animal and plant species from over fishing, pollution, drought and fires. Conservation projects also exist in government schemes, private reservations and local farming projects. Conservation is funded by private and public organisations both internally and outside of the continent as the area is of heritage value for the evolution of many species including humanity.

Energy Security First Ten Mark Answer

a)      Explain the possible impacts on UK energy security of the trends shown. 10mrks

There are issues facing the UK’s energy supply as facing the order to cut CO2 emissions the British government seek out viable alternatives. The UK is currently producing 400gs of CO2 per kg and is facing the shutdown of British coal stations to meet the EU quota of 50gs, a 75% decrease. The two possible routes currently hitting the headlines are either to follow the original plan into costly renewables and cleaner nuclear sources or to continue with business as usual by “dodging climate change targets” says Livermore and “dash for gas”. In this essay I will explore the trends shown in figure 1 and how they may indicate future insecurities.

The Overall trend in the amount of energy use shown in Figure 1 is not dramatically changed. The amount has only increased by 20million tonnes (in equivalent of oil) between 1970 and 2030, not much when the overall use in 2030 is expected to be a staggering 230million tonnes. This does not indicate insecurity as such because the increase itself is not outside of our capabilities to obtain the energy. We faced an increase double that (between 2010 and 2030) in the decades between 1990 and 2010. Therefore this increase of around 9million tonnes should not be impossible. The problems however are not with the overall figure but instead the individual energy sources within that figure and how we intend to replace our losses to meet this projection.

Coal is the primary issue. Looking at the trend, shutting down these stations in 2020 to meet targets should not be an issue as in the last 60 years the UK has decreased its coal output by almost 100million tonnes. However, coal still accounted for around 38million tonnes in 2010, the use of coal in 2030 is still predicted to be more than the usage for renewables and nuclear combined. In addition to the overall increase of around 9million tonnes this leaves a large deficit that if not filled may lead to energy insecurity.

There are further issues implied by the trend shown for nuclear power. The use of nuclear power has fluctuated in the past 60 years, rising by 10million tonnes between 1970 and 1990, and then decreasing back 10million tonnes by 2030. This is because the first stations in operation at 1990 had a short life and are now beginning to expire. This poses an issue for energy security in the UK as even with immediate investment into nuclear energy; the stations take 15-20 years to build. This leaves a gap as shown in the trend (nuclear only at 10million tonnes in 2030) where the UK will be without nuclear power, irrelevant of investment into it. This is estimated in the chart to be filled by an increase in natural gas and renewables.

However, there are also issues with these sources as natural gas is either found in the UK’s North Sea or is imported in liquefied form from Russia or Qatar. The source in the UK is quickly running out, meaning we must soon rely on imported gas. Qatar is a Middle Eastern country and is politically unstable. This may lead to energy insecurity as the import pathway for liquefied gas may be easily disrupted by war or revolution. Dependency upon Russia also makes our energy security vulnerable as the Russian government have been known to use their energy exports for political leverage. If both of these countries were to cut off supply and we were dependent on our own dwindling sources then loss of natural gas may lead to energy insecurity.

Furthermore, HEP and other renewables are also unreliable as despite the government’s religious investment into wind power the chart shows that renewables will only be less than 5% of the overall energy use in 2030. This is because renewables are expensive and only have a low output which is not constant. Furthermore oil is almost one third of overall energy use and has remained constant over the past 60 years being the same usage in 2030 as it was 60 years ago. This means the UK has always been dependent upon oil, making this difficult to change. This also makes the UK vulnerable to energy insecurity, not through physical scarcity but economic scarcity as OPECC control the UK’s provision of oil and have been notorious for changing these prices (such as the increase triple fold in 1977). Therefore these energy sources cannot be relied upon and the UK’s energy remains insecure.

Japan Case Study Notes

Japan

Q1 Tectonics

The meeting of four tectonic plates à

Destructive plates create Fold Mountains to form the series of islands.

Mt Kirishima = explosive composite volcano. 10% of the most active volcanoes are in Japan.

Japan is a part of the Pacific ring of fire which follows the Western boundary of the Pacific plate and here occur around 90% of all earthquakes.

Pacific plate sub ducts beneath the North American and Philippine plate to create the Japan Trench. ß Most volcanoes found along this point.

On average, the Pacific Plate is moving west at about 9cms per year, and the movement has produced major earthquakes in the past — nine earthquakes of magnitude 7 or greater since 1973.

http://www.ouramazingplanet.com/1048-japan-tectonics-explosive-geology-ring-of-fire-110314.html

Q2 Landscape

Japan is approximately 375,000km², consists of 2,456 islands in total.

Japan is located in Eastern Asia. It’s a series of islands east of the Korean peninsula.

The Japanese islands are the summits of mountain ridges uplifted near the outer edge of the continental shelf therefore 73% of Japan is mountainous (high relief) with a mountain range running through each of the main islands. (e.g. the Japanese Alps) The highest point on the island is Mount Fuji at around 12,400ft. ß High risk of landslides

There are a few plains and river basins many of which are near the coast and heavily populated. Areas around Tokyo for example are reclaimed (popular for buildings and harbours around the city). None of the populated plains or mountain basins are extensive in area. The largest, the Kanto Plain, where Tokyo is situated, covers only 13,000 square kilometres.

With expanding population there have been challenges with land space leading to human modifications:

·         Land extensions (reclaimed land, marshes)

·         Artificial islands e.g. Port Island in Kobe

·         Reclaimed land from river deltas, drainage

·         Carved/degraded mountainsides

Rivers no longer than 400kms, often small and steep river Shinano is the longest.

Islands difficult to get inland, rivers fast flowing and violent, roads rare therefore rural populations hard to reach in emergencies.

Q3 People

 Violent earthquakes, volcanic eruptions etc. high death toll but well prepared due to MEDC status and funds. See individual events for specific examples à

Q4 Management

Scientists carry out seismic monitoring of plates to provide warnings with sirens, education drills and emergency packs etc. ß However, the warning for the recent tsunami in 2011 was sent out only 15minutes ahead of the tsunami.

After 1995 in Kobe, the Japanese government created new laws to increase the standard of building regulations to withstand earthquakes.

Tectonic events

Kobe 1995  

An earthquake measuring 7.2 on the Richter scale in January 1995 of which the epicentre found beneath Kobe City ß significant damage was incurred because the epicentre was shallow in the crust hence the quake reached the surface quicker with less energy lost.

ß Caused by a slip fault between the pacific plate sub ducting beneath the Philippine plate.

Effects:

·         Pancaked houses (flattened) leaving 300,000 people homeless.

·         Crashing of gas pipes and electricity. ß +150 Fires in the city leading to over 1,000 deaths.

·         Hanshin Highway collapsed. ß Early morning low impact but cut of transport routes. Double storey highways, collapse also damaged surrounding buildings.

·         Liquefaction weakened building structures cracked roads.

·         5,500 killed in total.

Emergency resources were sent out but many did not reach those who needed it because of transportation problems.

‘Robo-rat’ was developed after the quake to find people in the rubble safely.