Yr11 - What causes earthquakes?

The above video gives you the basic details on what causes earthquakes.

This video explains the processes behind earthquakes in more depth explaining the different types of seismic waves.

Some useful websites = 

USGS science page

Live Science explains what causes earthquakes

BBC page for schools on earthquakes

Yr11 - Plate Tectonics.

Below are links to the videos watched in class this week.

plus some other useful ones :)

Yr 11 - Extreme Natural Events - Likely Questions and some simple essay plans!

In this assessment it is possible to predict the type of questions you are likely to get. They tend to always ask the following;

• What processes cause your chosen Extreme Natural Event (what causes earthquakes)?
• What impacts does your chosen Extreme Natural Event have on the natural or the cultural environment? (How do earthquakes affect people and cities or the natural landscape?)
• How did people respond to your Extreme Natural Event in the short or long term? (How did people react immediately after the earthquake and how did they respond in the days weeks or months after the event?)

Below are example of some of the questions you are likely to get along with brief essay plans. These are short sentences or bullet points with a summary of what you will write about in each paragraph. In the assessment you will need to write in full sentences and in essay style. These are just rough plans of what you could include in an answer.

Question 1

Fully explain the natural processes that operate to produce your named extreme natural event within the environment of your named case study. Also specifically asks you to include reference to the concepts of Process and Environment.

Paragraph 1 - An earthquake is caused by the movement of the earth’s crust and can cause a lot of damage and devastation. Process = Plate tectonics. The earths structure – crust, mantle, inner and outer core. Split into plates. (diagram of earth’s structure)

Paragraph 2 – What causes plates to move (convection currents). Plate boundaries – conservative/constructive/convergent(destructive or subductive).Destructive beneath NZ – Pacific + Australian plate. Build up of stress energy, release = earthquake. (possible diagram of plate boundaries)

Paragraph 3 – Plates beneath NZ Environment = causes of Christchurch EQ – previously unknown fault. Magnitude 6.3. Epicentre 10km to SE of CC centre. Followed 6 months after 7.1 magnitude quake.

Question 2

Fully explain how your named extreme natural event has affected the cultural environment.You may use diagrams, and include some of the ideas from the table below, to support your answer.

Cultural Environment = Created by man – so cities/towns/buildings/roads

Paragraph 1 – Intro – Caused wide spread devastation…many buildings/infrastructure destroyed. Details of EQ – struck at 12.51pm on 22^nd Feb 2011. 185 people killed. Fire + falling building causing many deaths (CTV building). Cost of rebuilding $20-30 billion. Tents set up in central park for people who’s homes had been damaged.

Paragraph 2 – Liquefaction – to eastern suburbs – damaging roads/homes. Roads/bridges/airport damaged causing problems for rescue efforts.

Paragraph 3 – Electricity/Power lost to many (on day of quake 80% of city without power) – took 5 days to get 82% reconnected.  Many lost water supply took a week to reconnect 70% of the city. Sewage and water pipes burst. 2000 portaloos had to be bought in and 5000 chemical toilets.

Paragraph 4 – loss of businesses/jobs due to damaged buildings and inability to access CBD. Depression and people leaving the area to live elsewhere – (CC no longer 2^nd biggest city in NZ). Loss of communities…..

Question 3

In the space below, describe the human response both during and after your chosen extreme natural event. You may answer in paragraph form or use a combination of diagrams and notes. Specific references to a named case study (or studies) must be included in your answer.

Paragraph 1 - Initial response.

•  Ordinary people helped to rescue those who were trapped
• Urban Search and Rescue was there within a couple of hours of the event.
• Emergency government cabinet meeting held at 3pm
• The Canterbury Art Gallery, which was earthquake proof, was turned into an emergency response centre.
• 300 Australian police were flown in
• The police provided security cordons, organised evacuations, supported search and rescue teams, missing persons and family liaison, and organised media briefings and tours of the affected areas.
• Chemical toilets were provided for 30,000 residents
• Areas were zoned (green, orange, white, red) to classify damage/cost of repairs
• International aid was provided in the form of money (around $6-7 million) and aid workers
• The Earthquake commission assessed all buildings to ensure they were safe.

Paragraph 2 - Long term response.

•  The Red Cross provided grants to families with children under 5years of age who were living in significantly damaged homes caused by the September or February earthquakes, with their electricity bills.
• The police coordinated forensic analysis and evidence gathering of fatalities working closely with pathologists, forensic dentists and scientists.
• Paid $898 million in building claims
• Provided temporary housing and ensured all damaged housing was kept water tight
• Water and sewerage was restored for all residents by August
• Roads and houses were cleared of silt from liquefaction by August and 80% of roads/50% of footpaths were repaired

Yr11 - The Impacts on People and Places - The Christchurch Earthquake

Below are a couple of videos that I linked to in class today. They show some of the short and long term impacts of the Earthquake.

Yr11 - Extreme Natural Events Assessment guidance

Here are some sample questions from the Extreme Natural Events assessments and some sample answers with their grades.

1.Read the following Geographic Concept. Include specific references to it, as well as to the extreme natural event and to the environment of the case study (studies) you have named on page 2, to support your answers to this question.

 Fully explain how your named extreme natural event has affected the natural environment.

Volcanic eruptions can have many effects on natural environments. The natural vegetation is stripped bare and trees lose their leaves. Forests may be burnt. Often all the trees fall in the direction of the blast. New landforms are created and others destroyed. New cones can appear or craters fill with rainwater to create new lakes. Sometimes the eruption is so large that the top of a mountain is blown off so that its height is reduced or the sides collapse as they are unstable to form a caldera. Soils are also affected. Straight after an eruption the ash covers the ground making it hard to grow anything. However, over time the soils become more fertile. Waterways are changed by debris from lahars. If there are lots of lava flows they may fill up a river valley and change the shape of the land. Coastlines are only affected if the eruption occurs near to the sea when they can change the shape of the coastline.

Overall Mark – Not Achieved

Main Reason: No reference to a case study

2.

Read the following Geographic Concept. Include specific references to it, as well as to the extreme natural event and to the environment of the case study (studies) you have named on page 2, to support your answers to this question.

Fully explain how your named extreme natural event has affected the natural environment.

When Tarawera erupted in 1886 it had a major impact on the environment. It was a huge eruption, measuring a 4 on the Volcanic Explosivity index (VEI). This was so large that it was recorded by the ancient Chinese who saw strange red skies. The eruption started just after midnight with a series of small earthquakes. The first eruption happened about 1.30am with a huge cloud of ash. At this time most people were in their houses hiding as they were scared and did not know what to do. When the ash fell on the roofs of the houses they collapsed under the weight. 153 people were killed in 3 Maori villages such as Te Wairoa. This could have been avoided if people had been evacuated. Today scientists are much more able to predict if an eruption is likely. When Pinatubo erupted in 1991 this was also a large eruption measuring a 5 on the VEI scale. However, an effective evacuation by the government saw 370,000 people in the 30km radius of the volcano moved to safety elsewhere. This shows that volcanic eruptions can have big impacts on environments.

Overall Mark: Not Achieved

Reason: Is all on impacts of cultural environments not natural.

3.

Read the following Geographic Concept. Include specific references to it, as well as to the extreme natural event and to the environment of the case study (studies) you have named on page 2, to support your answers to this question.

Fully explain how your named extreme natural event has affected the natural environment.

When Tarawera erupted in 1886 it had a major impact on the environment. This eruption was very large measuring a 4 on the volcanic Explosivity Index meaning that it could do a lot of damage to the natural environment. One impact that it had was that it changed  lake Rotomahana. Before the eruption this lake was fairly small and well known as the site of two silica terraces called the Pink and white terraces that were a major tourist attraction at the time. When the eruption occurred just after midnight on June 10^th 1886 the hot lava hit the cold water of the lake and caused a massive explosion. The water was turned into hot mud that rained down across the whole region and buried it. A large hole was left where the lake stood. Over time this hole filled with rainwater to form the present lake. This is now more than double its original size and is 40m higher than before the eruption. This shows that volcanic eruptions can cause big changes to the shape of the environment.

Overall Mark: Not Achieved

Reason: Only one impact on the natural environment is mentioned.

 4.

Read the following Geographic Concept. Include specific references to it, as well as to the extreme natural event and to the environment of the case study (studies) you have named on page 2, to support your answers to this question.

Fully explain how your named extreme natural event has affected the natural environment.

When Pinatubo erupted in June 1991 it caused many effects on the natural environment. The vegetation that covered the mountain sides was stripped bare. The soils were made infertile causing a food shortage. The rivers that had their source on Mt Pinatubo such as the Maloma were all changed as they were unable to flow along their original path. Most dramatic of all was that a new caldera was formed that was 2.5km wide. The highest point of the caldera rim stood 260m lower than the pre-eruption summit. This shows that volcanic eruptions can change natural environments.

Overall Mark: Achieved

Reason: Has several impacts on natural environments and case study specifics. However, this is descriptive only and does not give reasons for the effects needed to lift to Merit.

5.

Read the following Geographic Concept. Include specific references to it, as well as to the extreme natural event and to the environment of the case study (studies) you have named on page 2, to support your answers to this question.

Fully explain how your named extreme natural event has affected the natural environment.

Volcanic eruptions can have many effects on natural environments as can be seen by the case studies of Tarawera (1886) and Pinatubo (1991). Both of these eruptions were very large and explosive measuring 4-5 on the VEI (Volcanic Explosivity index). Because of the size of the eruption they had major effects on relief. On Tarawera the top of the mountain split open along a 17km long line. This went through a nearby valley and as the hot magma came into contact with cold lake water it turned it to steam, ash and mud. This rained down over the area burying valleys and destroying forests. The ground was covered in up to 8m of mud that made the soils infertile for the next 10 years. Features such as the Pink and White terraces were destroyed while the holes left by the explosions later filled with rain creating new lakes such as Lake Rotomahana. In the Pinatubo eruption the explosion was so vast that it created a caldera 2.5km wide.  The river systems were all altered as they were clogged with volcanic sediment. Minerals such as lead were brought to the surface making soils infertile.

Overall Mark: Merit

Reason: Has several impacts on natural environments that are explained with good case study evidence. Lacks reference to change needed for excellence. 

Yr11 - Extreme Natural Events - Likely Questions :)

Understanding the question from lavenderbongo

The slideshow above takes you through some of the most common questions that tend to be asked during the Extreme Natural Events assessments.

Yr11 - Plate Tectonics Revision

You need to be able to explain the processes that cause earthquakes. This means that you need to be able to explain how and why earthquakes occur.

Earthquakes happen every day in New Zealand. There are around 14,000 earthquakes in and around the country each year. Most are too small to be noticed, but between 150 and 200 are big enough to be felt.

The earthquakes are caused by the movement of the earths crust which is broken into sections called plates. These plates float on the liquid rock of the Mantle. The plates are moved by convection currents in the mantle, which circulate round forcing them to move towards and away from each other. They move at a very slow rate, normally just a few centimeters each year. About the same rate as finger nails grow.

Earthquakes are most common in areas where two plates meet. These areas are called plate boundaries. New Zealand lies on the plate boundary between the Pacific Plate and the Australian Plate.

When two plates are forced together, or past one another, they sometimes get stuck and stress energy builds as they try to keep moving. When they finally move this energy is released and an earthquake occurs. The energy is released in the form of seismic waves which travel through the earths surface. Earthquakes normally take place at faults which are existing cracks or fissures in the earths crust.

The strength of the earthquake depends on the size of the movement and the depth of the movement. The deeper beneath the earths surface that the actual movement occurs (the focus = point at which the earthquake or movement actually occurred) the less it will be felt at the surface (the epicenter = point on the earths surface directly above the focus). The shallow earthquakes, ones where the movement is nearer the surface, are they ones that tend to cause the severe damage.

Yr11 - Assessment practice on Extreme Natural Events

The question below is an extract from a past paper on Extreme Natural Events.

Answer the question in the comment section below this post. The person who writes the best answer will win a small prize!

  

yr11 - Impact on the Natural Environment from the Christchurch Earthquake

Yr11 - Canterbury Earthquake - useful links

Great images of the city before and after the quake.

The video below is from GNS science and describes the impact of the seismic waves on Christchurch

A documentary about the Christchurch Earthquake

Yr11 - Natural Hazards in New Zealand

Some great videos on New Zealands Natural Hazards from GNS Science.

Video on the Tsunami Hazard in New Zealand

Big Earthquakes double in 2014

It appears there have been more large earthquakes than normal this year! Although apparently it's nothing to worry about.

http://www.cbsnews.com/news/big-earthquakes-double-in-2014-but-scientists-say-theyre-not-linked/

Pacific Ring lights up!

This morning there has been a couple of large quakes around the Pacific Ring or fire. One not far from New Zealand.

The article linked to below describes what happened in more detail.

Article from Stuff News

Awesome timelapse map of Earthquakes

Great time lapse map of global earthquakes in the first few months of 2014

Quite startling when you look at the number and frequency of earthquakes so far this year. Something is certainly moving under the pacific rim!

Yr 11 - Christchurch Earthquake

Christchurch earthquake Feb 2011

More PowerPoint presentations from Ivor Jones

Yr11 - Rockfall impacts from Christchurch Earthquake

Yr 11 - How Liquifaction occurs.

Great video illustrating how liquifaction occurs.

Yr11 - Earthquakes and how to locate them.

A great clip describing how earthquakes are located in New Zealand.

Click on the link below to get to the GNS website which has lots of up to date info on the Christchurch Earthquake and how it has changed the landscape.

Canterbury Quake - the latest from GNS