Earthquake Theory and Fieldwork

1) Earthquake theory

(i) What is an earthquake?

    

An earthquake is a sudden movement of the earth’s crust caused by the release of stress accumulated along tectonic plate boundaries or fault lines.

(ii) Why do earthquakes form?

The Earth’s surface is divided into pieces which all interlock each other like a jigsaw. 

These plates aren’t stationary. Below them there is hot liquid magma which makes plates move. When the plates move because of the hot magma underneath and make contact with another plate, energy is produced. The energy produced can be felt on the Earth’s surface through seismic waves. This is what we call an earthquake.

(iii) How do earthquakes form?

 The plates can interact with each other in four ways:

Boundary 

Plates Involved 

What Happens

Result 

Example

Destructive

Oceanic and Continental 

The denser oceanic plate subducts the continental plate causing hot molten rock to form and rise. This creates a volcano.

Volcano, Earthquakes and fold mountains

Nazca and South American Plates

Constructive

Oceanic and Oceanic 

Two plates move away from each other forcing hot magma to rise from underneath. 

Volcano and Earthquakes

North American and Eurasion Plates – Iceland

Collision 

Continental and Continental 

This is where two continental plates collide together and neither can sink hence forcing material upwards.

Earthquake and fold mountains 

Indian and Eurasion plates – Himalayas

Conservative 

Any 

Two plates slide past each other usually getting stuck. This builds pressure and when they finally release the pressure there is sudden movement.

Earthquake 

North American and Pacific Plates – San Andres Fault

(iv) Where are earthquakes usually found in the world?

The take place all over the world. They don’t just occur on plate boundaries, they also occur on minor faults. 80% of all tectonic activity take place on the boundary of the pacific plate. This includes; the Philippines islands, New Zealand, and Japan.

2. Earthquake fieldwork

(i) How can we measure the magnitude of an earthquake?

There are two ways of measuring the magnitude of an earthquake (i) the Mercalli scale and (ii) the Richter scale.

Mercalli scale

The Mercalli intensity scale is a numerical and subjective way of measuring the magnitude of earthquakes. It is a scale between 1-12; 1 being nothing being felt and 12 total destruction. The scale isn’t used very much today because it isn’t accurate because different will have different experiences which will reflect the different scores given to different earthquakes.

Richter scale 

The Richter scale is a numerical and objective way of measuring the magnitude of earthquakes. It is a scale between 1-10; it has a logarithm scale i.e. an earthquake measure 4 on the Richter scale is 10 times as big as one measuring 3.  This is the most popular way of predicting earthquakes today. It works by using seismometers to measure the seismic energy released.

Test on global hazards

Use this test to make sure you know about global hazards. In addition, please look at the different ways of presenting hazard profiles.

  1. Define a natural hazard. (2)
  2. Identify and define with examples the four types of hazards. (8)
  3. State whether each of the events below is a hazard, if so what type and why is it/is it not   a hazard;
  • A drought in the South East of England. (3)
  • A flood in a rural area which floods the roads, but doesn’t affect any houses.(3)
  • An avalanche, high on mountain slopes, remote from any settlement. (3)
  • A tsunami 50 cm high off the coast of Japan. (3)
  • A volcano erupting on a remote unpopulated island. (3)
  1. Define a windstorm. (2)
  2. Name two case studies of each type of hazard;
  • Flood (2)
  • Earthquake (2)
  • Windstorm (2)
  1. How would Swiss Re define a disaster? (3)
  2.  What is a vulnerable population? (2)
  3. What is a quasi-natural hazard? Give an example with it. (3)
  4. What are the six indicators used to assess the impact of a hazard? (6)
  5. What is the risk equation? (3)

_______________________________________________________________________________________

Answers

  1. A natural hazard is a natural event or process, which involves people. (2)

Candidates may also give example e.g. loss of life, injury, disruption, economic damage or environmental degradation.

  1. Hydro-meteorological (1) — these are hazards caused by weather conditions & water (1)

Geo-physical (1) — these are hazards caused by processes of the earth. (1)

Geomorphic (1) — these are hazards caused by external earth processes involving mass movement (1)

Tectonic (1) — these are hazards caused by tectonic activity; earthquakes, volcanoes and tsunamis. (1) (to get 1 mark for tectonic hazards candidate is not required to give examples)

  1. a) It is a hydro-meteorlogical hazard (2) Chose one from the following 3 reasons;

– Because it will affect the agricultural yield for England. (1)

– Extreme heat may affect some people’s health. (1)

– There may also be concerns with water supply. (1)

b) Hydro-Meteorlogical hazard (2)-because it affects roads which affects people because they may be blocked from going to work or school and residents experience general disruption (1)

c) It is not a hazard because being remote it affects no one. (3)

d) Tectonic hazard (2) because it affects people living on the coast of Japan e.g. injury, loss of lives, economic damage etc (1) Candidates do not need to give an example to get one mark

e) It is not a hazard because there are no people involved. (3) It is just a natural event.

A storm with high or violent winds (1) with no or a little precipitation (1)

(a) (i) Boscastle August 2004 (ii) Mississippi flood 1993 (2)

(b) (i) Kobe earthquake January 1995 (ii) California earthquake 1989 (2)

(c) (i) Lady Lake tornado 2007 (ii) Windstorm Klaus January 2009 (2)

Candidates may pick other examples e.g. Haiti earthquake Jan 2010 – year it happened is required but month isn’t.

  1. A disaster, which caused at least 20 people to die (1), or insurance damage (1) of over US $16 million. (1)
  1. A vulnerable population is one that is susceptible to human or economic loss (1) because of the geography of where they live. (1)
  1. A quasi-natural hazard is a hazard, which is caused by a bi-product of human activity (especially while using natural resources) (2) . For example, in Indonesia (2006) a mud volcano erupted killing and disrupting many lives. It is claimed that a company called Lapindo Brantas caused it. (1) Candidates may use other examples.
  1. i) Duration (1) — Period of time over which it occurs
  2. ii) Area reliability (1) – Could you predict the area that was affected e.g. you can predict where a volcano will reach but you can’t for a

iii) Magnitude (1) — How big is it compared to the average

iv) Frequency (1) – How often-on average does the even happen?

v) Speed of onset (1) – Length of time between first appearance and peak e.g. lag time in flooding

vi) Area extent (1) – How big is the region affected?

(Note: Candidate do not need to give explanation to get the mark, the indicator on its own is fine)

10. Disaster risk = (Hazard x Vulnerability) / Capacity

A mark each for each part being in the right space.

National Geographic (April 2010) – Water issue

In this video, I discuss a few points I had while reading the April 2010 special edition of water issue. I discuss the water crisis and the solution technological advancements in desalination present. Then I go on to discuss what economic benefits this solution can bring, in theory. Finally, I question why out of all elements water is the most important one.

Dealing with climate change: Adaptation vs. mitigation

 

There are two approaches to dealing with climatic change: MITIGATION and ADAPTATION.

MITIGATION

Mitigation refers to policies that attempt to prevent further global warming and they are strategies which try to get rid of or reduce global warming e.g. using carbon tax to reduce the amount of greenhouse gases being emitted into our atmosphere.

ADAPTATION 

Adaptation refers to policies that attempt to cope/deal with climatic change. They are not strategies which try to get rid of global warming. They are trying to cope with the impacts of climatic change e.g. introducing drought resistant crops.

So Lets look at some of the policies…

Mitigation

Adaptation

Wind Farms – By producing more energy by wind farms we can use renewable fuels less which emit greenhouse gases and try and prevent global warming.

Coastal defence – Through climate change our coasts are increasingly becoming a risk especially as sea levels rise. So coastal defence can include things like a sea wall, rip-rap etc.

Transport reformation – By changing our modes of transports or how they are run e.g. switching to biofuels is another way in which we can cut of greenhouse gas emissions. This also includes creating incentives for people to use more public transport rather than private transport.

Diversify agriculture –  This includes things like exploring different plants to grow and in different areas. Global warming means temperatures in different places are changing so by diversifying crops we are sure to have some which can grow in the new conditions that climatic change presents.

Afforestation –By planting trees/plants we are offsetting the carbon we produce hence reducing the net greenhouse gas emissions. This is known as carbon sequestration.

House Design – Global warming means our houses are continually becoming at risk of a variety of hazards and more than before. So we have to design our houses in such as a way that they can cope with lets say increased flooding risks. Double glazing is one example of how we can protect our homes from increased hazards.

Solar Panel – So as you can see many of these methods include alternate energy productions. This is because this cuts the amount of energy we need from carbon fuels which heavily emits greenhouse gases.

GM Foods –  Just like why we have to diversify our agricultural range, we have to invest in genetically modified crops and plants because this means we can still get a high yield for our exponentially growing population as well as coping with increased risks of lets say droughts.

Congestion Charge – So this is a deterrent for people to stop using there private transport too much – again a method cutting emission of greenhouse gases.

Better warning/forecasting systems – So the key element here is that climatic change means that we all are at risk from increased number of hazards hence we need to be more prepared. One way of doing this is by investing in our warning and forecasting systems. (particularly in LEDCs)

Regulate burning/chopping trees/plant – this is part of carbon sequestration and by using more regulation we can limit the number of trees/plants this happens which 

 also reduce the net carbon emissions.

Emergency plans – This is similar to better warning/forecasting systems except here leaders need to devote time and funds to preparing emergency plans and enforce regulations to ensure people are prepared for any major hazard.

Energy efficient appliances – We can not only encourage the use of energy efficient appliances, we can invest in innovation and R&D of such green appliances.

Domestic efficiency – Again by becoming more efficient we are cutting the amount of greenhouse gas emissions we send to the atmosphere. This type of efficiency including insulation homes, double glazing etc.

So which is better adaptation or mitigation? Lets look at some of the benefits of each strategy…

Pro- Adaptation

Pro- Mitigation 

It is time consuming to get all the countries to multilaterally come to a decision about how to reduce carbon emissions let alone cease them.

We should reduce emissions immediately to avoid being a position where climate change is irreversible.

The time on trying to get countries to mitigate climate change means that it might get much worse before we see green shoots.

Unless we challenge global warming then change will never arise in our energy production and other aspects of our life.

Climate change has already happened e.g. melting Arctic ice so we have to react and manage the situation now.

Policies such as carbon sinks are easily achievable e.g. the government just needs to provide a couple of grants for afforestation.

Even if emissions were to cease today then greenhouse gases already present in the atmosphere would cause changes at least for the next century. CO2 has a life for 100 years!

Mitigation methods are politically recognized in developed nation hence this means they are important and the rest of the world should follow on.

The Earths absorbs CO2 slowly so even with increased carbon sinks ( e.g. afforestation) it will take time for all the excess CO2 to be absorbed.

It is claimed that cutting greenhouse gases adversely affects economic growth. However, this is not true. In Western countries emissions are constant or falling and economic growth is pretty strong so we should seek more mitigation strategies. 

Keeping carbons emissions at where they are at or reducing them is unrealistic especially with BRIC countries such as China and India which have rapid economic growth. Hence we need to adapt as we might be too late to mitigate!

REVIEW TEST

  1. Define Mitigation strategies
  2. Define Adaptation
  3. Give the two main ways in which we can mitigate climate change
  4. What is the main way we can adapt to climate change
  5. Give one advantage of adaptation policies and one of mitigation policies

Suggested Answers 

  1. Mitigation strategies are policies used to try and reduce/ get rid of climatic change.
  2. Adaptation are policies used to try and cope/deal with climatic change.
  3. The two main ways we can mitigate to climate change is by reducing greenhouse gas emissions through energy production and by changing lifestyles e.g. switching to public transport.
  4. The main way we adapt to climatic change is by preparing all aspects of out life for increased risks
  5. One advantage of mitigation strategies is that if we act now we might be able to prevent reaching a situation where climate change is irreversible. One advantage of adaptation strategies is that instead of trying to mitigate something which has probably happened (E.g. Arctic ice melting) we can fortify ourselves for the impacts and be prepared.

Rising Sea Levels & Bangladesh

RISE IN SEA LEVELS 

AIM:  To investigate how sea level rise may have a disproportionately bigger effect on some countries like Bangladesh.

Modelling the rise in sea levels 

There are various predictions for sea level rise for the future. The mode extreme one predicts a rise in sea level by 15m by 2100. This puts many places including London in peril. But how is this 15m going to be achieved?

  1. Melting of West Arctic ice sheet = 5m rise
  2. Complete melting of Greenland ice sheet  =  7m
  3. Collapse and melting of world’s glacier system = 2m
  4. Continual thermal expansion of oceans = 1m

So all four event equal a 15m rise in sea level.However, most models produce a rise of 1m. Nevertheless, it is important that we act fast because even if the probability is small the risk of sea levels rising is so great. There are 3 key fundamental reasons why it is so difficult to model sea level rise hence the vast set of results.

The first reason is that it is difficult to predict the quantity of future greenhouse gas emissions especially as that isn’t just based on us it is based on nature e.g. volcanic eruptions. The second is based on the concept of ceteris paribus which is the concept that all other things remain the same i.e. ‘business as usual’. Finally, it is difficult to predict the actual impacts of a rise in sea levels.

There are two types of changes involved when we are discussing sea level changes: EUSTATIC & ISOSTATIC. Eustatic changes involve changes in sea level due to the amount of water in oceans and isostatic changes involves movements of land in response to changes in sea levels.

So where are the most vulnerable places?

There are three types of area which are most vulnerable to changes in sea level rise.

  1. Land on river deltas e.g. Bangladesh
  2. Areas that lie close to sea level e.g. Netherlands, Eastern Britain
  3. Small low lying islands in the Pacific oceans e.g. Tebua

CASE STUDY: Bangladesh

Background

  • 70% of the country lies on flood plains, less than 6m above sea level
  • Faced by multiple varieties of hazards
  • Has a growing population 
  • It is an LEDC
  • It is the world’s most densely populated area
  • It is a mega-delta filtering 57 river including Ganges, Meghna and Brahmaputra. In addition it filters snowmelt from Himalayas, monsoon rains and high tides.

What happens if sea levels rise

  • It could loose up to 20% of its land
  • Displace 40 million people
  • Threaten food supply, drinking water and agricultural land
  • Increasing water temperatures can lead to increased number of water borne diseases such as Cholera
  • The biggest risk is being lost like Tebue which means that tens of millions of environmental refugees will have to seek livelihood in other countries.
  • Damage to coral reefs 
  • More risk of cyclones
  • Malnutrition
  • Child development and education will be negatively affected 
  • Loss of properties 

So how are Bangladesh acting right now?

  1. Technological solutions – In the 1990s, Dhaka the capital city – cleared 102km of drains and constructed 144km of drains. They also opened 633 channels to improve drainage
  2. Early warning/ flood predictions – This includes preparing people especially the vulnerable of floods e.g. allowing people to be evacuated to safer grounds quickly and effectively
  3. Behavioural – Changing land uses and food choices e.g. increase fishing more than arable farming. Bans have also been put in place to slow down urbanisation
  4. Managerial – e.g. improve sanitation and water management to prevent water-borne diseases.

The solutions presented in this post are one thing but Bangladesh only has limited funds and there is a limit to how much they can borrow or rely on international aid. They also have a large vulnerable population and protecting every single citizen isn’t easy. Bangladesh has to think ahead as climate change provide more extreme situations of flooding etc then they have prepared for.

REVIEW QUESTIONS

  1. Define Eustatic changes.
  2. Define Isostatic changes.
  3. What are the three reasons that make modelling difficult?
  4. What is extreme quantity of sea level rise predicted?
  5. What are three most vulnerable places in regards to rising sea levels
  6. State two facts about Bangladesh
  7. Name three impacts of rising sea levels in Bangladesh
  8. Name two solutions Bangladesh plans
  9. What are the two fundamental  problems with these solutions?
  10. What are the three main rivers of the 57 that make Bangladesh a mega-delta?

Suggested Answers

  1. Eustatic changes are changes caused by changes in the amount of water in oceans
  2. Isostatic changes are the responses of land to changes in sea levels
  3. It is based on the concept of ceteris paribus, it is hard to predict future greenhouse gas emissions and we do not accurately know the impacts of rising sea levels
  4. 15m 
  5. Large river delta e.g. Bangladesh, the Nile, places with low lying land such as Netherlands or Eastern Britain, small low lying islands in the Pacific or Indian ocean
  6. Almost 70% is a flood plain which lies on less than 6m above sea level and  has the world’s most densely populated area
  7. 40 million people will have to be displaced, risk of water borne diseases such as Cholera and risk to properties and livelihoods 
  8. Technological 633 channels to improve drainage and managerial improve sanitation and waste management
  9. Bangladesh does not have the funds and has a large vulnerable population
  10. Ganges, Meghna and Brahmaputra

Fieldwork and Research: Urban Strategies

Fieldwork and research into urban strategies that have been used for rebranding

In the table below I look at Primary and Secondary methods to explore the strategies that have been implemented to rebrand an area. 

Strategies that have been implemented

Primary methods

Secondary methods

Flagship

Interviews – We could interview developers on what their plans are to construct and what they hope to achieve from it. We could record the conversation on electrical devices such as voice re cords. Then we could transcribe the interview and analyse what they said.

Notes – We could look at the notes of developers and constructers

Retail value survey- Flagship developments including shopping centres and department stores. So in a retail value survey we can examine the amount and types of shops in different areas of the urban area.

Footfalls-  This ties in with Retail value survey but here we look at the amount of people entering a shop. This helps us get some idea of how much money is being created by flagship developments like Selfridges in Manchester.

Building usage – By examining building usage we can explore what kind of flagships are being added and what already exist. 

ACORN/CAMEO and GIS

Both of this helps us get data on the socio-economic parts  of a town which is important when considering regeneration.

Housing

Questionnaires – Questioning local residents on this aspect of rebranding is extremely important.

Census – This can tell us data such as average number of person (s) per room, average rooms in a house etc.

Waterfront

Environmental quality –Waterfronts are used to take advantage of natural features to create a better environment. So these survey can help to see whether development of waterfronts are needed.

Goad maps – Through this we can compare natural features of the past to features of today.

Photos – This is another method is which we can see how well environmentally regeneration has done or whether it needs rebranding and what about waterfronts – are they in good condition?

Regional and cultural events

Clone towns- In rebranding it is easy to be temped to create a clone town. So by using cultural and regional events we can prevent this from happening. By just walking around the area we can figure whether it is a clone or original town.

Visitor surveys – Visitors who come for this unique regional / cultural event should complete form to find out whether they are good or need improving.

Websites and Blogs/forums 

Both internet forms of research can help us to find out about any regional or cultural events that are on and what people’s views are on this.

Using sport as a catalyst

Oral histories/interview – They can tell us what in their opinion is the impacts of using sport as a catalyst for rebranding.

Upmystreet.com – Like Census but the profile section can tell us how well a place has come on after using sport as a catalyst

Redevelopment in coastal region

Sphere of influence, Placecheck and

Create land use maps

All three help us to see how redevelopment has changed a coastal town like Blackpool and identify the strengths and weaknesses of the town.

Brochures/ leaflets – We can see what the area offers and see is it sufficient? 

Blogs/forum – This will tell us what people think about the experience the place offers.