Transcript revision-lesson-theory-des-exp-case-studiesx

Restless Earth Revision
Levelled Objectives (What are we learning?)
L1. identify tectonic landforms
L2. describe & explain landforms
L3. explain the effects of tectonic hazards
Key words:
Tectonic Plates
Oceanic Crust
Continental Crust
Destructive Margin
Collision Margin
Learning to Learn (How are we learning?)
* Revising – going over what you know –
reflectiveness
* Reasoning – explaining – resourcefulness
What to do: identify the features in the photos, make notes
about landforms, describe and explain case studies
Conservative Margin
Constructive Margin
Volcanoes – Composite, Shield, Calderas
Earthquake
Tsunami
Homework: Revision – Geography
exam on the 9th Dec – Tectonics,
Rivers, Coasts.
Photos of tectonic features
Photos of tectonic features
Answers?
Caldera
Composite Volcano
Shield Volcano
Ocean Trench
Tsunami
Fold Mountains
What do you need to know?
• Some of the theory
• Volcanoes – description, explanation of formation, differences
between types, 2 case studies – one rich, one poor, how they are
monitored
• Earthquakes – description , explanation of formation, tsunamis, 2/3
case studies – one tsunami, one rich, one poor, how they are
monitored
• Fold Mountains – description, explanation of formation, 1 case study
about how they are used
Theory
• Earth’s Structure
• Types of Plates
• Types of Boundaries/Margins
Structure
Plates
Study of fossils
Similar fossils are found on different continents.
This is evidence that these regions were once very
close or joined together.
Pattern of rocks
Similar pattern of rock layers on different continents is
evidence that the rocks were once close together or joined.
Shapes of continents
Some continents fit together like a jigsaw.
Africa
South
America
Continental drift
Why do the plates move?
Plate names
North
American
Eurasian
Pacific
Pacific
African
Nazca
South
American
Indo-Australian
Plate
Antarctic
Margins/Boundaries
What are the
characteristics?
What landforms do
we get at each?
What tectonic
events?
Fold Mountains & Ocean Trenches
• Fold Mountains
• Occur at destructive and collision boundaries
• Have synclines and anticlines
• Plates push together forcing land upwards (often old
sea beds – presence of fish fossils in the Himalayas)
Fold Mountains & Ocean Trenches
• Ocean Trenches
• One plate subducts under another
• Plates ‘pull’ downwards creating a trench running parallel to the plate
boundary
Case Study - Andes
Human Activities:
For the people living in the Andes, the
steep slopes and harsh climate are
challenges to be overcome, but the
region does provide opportunities for
farming, energy production, mining and
tourism.
Farming – Sowing corn and beans, using
cattle to plough the soil. Traditionally
farmers have employed a system called
‘waru waru’, which involves creating
raised fields surrounded by ditches for
drainage.
Irrigation has been used in the Andes
for more than 6,000 years.
Farmers use terracing to cope with the
steep slopes.
Potatoes are grown widely throughout
the Andes as a staple crop.
Cash crops include cotton, tobacco and
coffee, which are mostly grown in the
sheltered and more fertile valley
bottoms.
Background Info:
The Andes are the longest chain of fold mountains in the world,
stretching for 7,000km north-south along the western side of South
America. The mountain chain is about 300km wide and has an average
height of 4,000m. They occur along the boundary between the Nazca
Plate and the South American Plate. The Nazca Plate is subducting
under the South American Plate as it is less dense.
Energy – Steep mountain slopes and high rainfall make the Andes
ideal for hydroelectric power production. The Yuncan project in Peru
(above) includes 16 miles of tunnels. Hydroelectric power makes up
50 per cent of energy production in Ecuador, Bolivia and Peru.
Mining – The Andes have rich deposits of copper, gold, tin and iron.
The Yanacocha gold mine in Peru is the largest gold mine in the
world. It is an open cast mine and the rocks containing the gold are
blasted with dynamite. The rock is then sprayed with toxic cyanide
and the gold extracted from the resulting solution. This can
contaminate water supplies. The nearby town of Cajamarca has
grown from 30,000 when the mine started to 240,000 people in
2005.
Tourism - The Inca Trail is 45km and leads to
the ‘lost city of the Incas’, Machu Picchu. As
more than 400,000 people visit the ancient city
every year, there is concern about damage to the
environment. The trail is strictly controlled, and
only 500 trekkers are allowed to start out on the
trail every day.
Volcanoes
• Composite
• Shield
• Caldera/Supervolcano
How Do Volcanoes Form? – leads to 2 different eruptions
Composite
Shield
Supervolcano/Caldera
Case Studies
• Mt St Helens
• Montserrat
• Etna
VEI of 6. Plume was more than
Tectonic Setting:
30km high. More than 10km3 of
It is located at the plate boundary between to the
erupted material.
Eurasian and Philippine Plate. It is the result of the
Social Effects Economic Effects Environmental
Oceanic Philippine plate being subducted under the
effects
lighter Continental Eurasian plate. It exploded in 1991
58,000people
Houses and bridges Volcanic ash is
and had some catastrophic effects, both for the
had to be
destroyed and
blown in all
people of the Philippines and the USA air force at
evacuated from needed replacing
directions over
Clarke airbase.
a 30km radius and Manila airport hundreds of KMs, Prediction Prevention
Preparation
Responses
of the volcano had to be closed
smothering fields What they 75,000 people were 75,000 people
Evacuation
actually did evacuated due to
evacuated up to a
camps built for
and buildings.
accurate
radius of 30km. USA refugees.
847 people lost Heavy rainfall from Fast flowing
predictions. There air force helicopters Warning sign like
their lives, 300 Typhoon Yunga
volcanic mudflows
was no monitoring helped.
gas and steam
until the 3rd of
Alert systems put
looked for. Long
killed by
causes buildings to (lahars) cause sever
April but
into place to warn of and short term
collapsing roofs collapse.
river bank erosion,
seismometers were eruption.
aid organized
and 100 by
undercut bridges
put into place.
Government
especially from
lahars.
etc.
The United States Shelters.
the Red Cross
Geological Service
and the United
1.2 million people Farmland destroyed Global cooling
helped to predict
States
lost their homes by falling ash and
caused by ash in the
the disaster
around the
pumice, unusable for atmosphere of
What they Set up permanent Placed strategies for Storage of
could have monitoring points or long term aid and
medical supplies
0.5°C
volcano and had years, the 1991
done
use satellite images disease control in
food and water
to migrate to
harvest was
to look upon volcano evacuations prepared in preparation
shanty towns
destroyed and
site for changes in for.
for disaster.
in Manila.
650,000 people lost
land surface.
their jobs
Mt Pinatubo
Etna
Tectonic Setting:
Located on a destructive boundary between the African and Eurasian plates. N
African plate is subducted. It is located on the island of Sicily. Previous
eruptions have created fertile soils. Mt Etna is a ski resort. Largest volcano in
Europe and is a composite volcano (formed on top of an ancient shield volcano).
More frequent eruptions than other composite cones like Mt Pinatubo.
Effects:
Eruption started on 14th
December 1991 and lasted
for 473 days – most
voluminous Etna eruption
from Etna in over 300 years
(250m cubic metres).
Acidic lava – low effusion
rate – no threat to human
life.
Lava destroyed springs which
provide water to Zafferana
(pop 8,000).
Millions of Lira of damage
done to property..
Vineyards and chestnut
orchards were destroyed.
VEI of 2 - continuous flow
of lava and tephra/ash
eruptions. Slow moving lava
(effusive). 2001-2 there
was an eruption with VEI of
3.
Responses:
Locals complained about a lack of preparation/response from government.
There was a lack of fear, “when there will be a lava flow it will be diverted
anyway.” Millions of Lira of damage done to property.
1992 – earth barrier built (400m long, 20m high) to stop lava reaching
Zafferana. Overflowed after a month. 3 more smaller constructed.US
marines used explosives to blast a whole in the lava tube and use helicopters
dropped concrete blocks into the main flow to slow it. Diversion channel was
dug and explosives used to divert the lava away from Zafferana.
Methods to improve monitoring have been introduced – radon gas
measurement, GPS monitoring slopes, sensitive seismometers to measure
tremors.
Montserrat
Effects:
Over 2/3rd’s of the population left to go to a
nearby island, or the UK, where the
government offered temporary living areas.an estimated 11000 moved away.
Main city Plymouth was destroyed, including
the airport.
Plymouth was covered in 40 feet of mud.
19 people died.
Pyroclastic flows reaching temperatures of
1000oC and flowing at 120 km/h. Debris was
showered into the zone marked safe.
Large ash clouds regularly being erupted
above the island, sometimes being up to 7010 thousand feet.
Dome inside the volcano growing and
therefore will collapse. The collapse later in
the year led to large and destructive
pyroclastic cloud and flows down the White
River, and hence creating a new delta.
During 1998, there were many small
earthquakes leading to the dome collapsing
again, and so more eruptions lasting 2 hours
30 minutes.
Tourist industry was destroyed, leaving many
with little money. Even now, few tourists
visit the island.
Tectonic Setting: Montserrat is an island prone to volcanoes and earthquakes
because The South American Plate and the Caribbean plate move towards
each other, and the South American Plate goes under the Caribbean plate,
and causes earthquakes. Magma rises, and under extreme pressure, erupts in
the form of a volcano. Eruptions from 1992-1997. 21st Aug 95 – Phreatic
eruption (steam-driven). 1996 – 1st pyroclastic flows move down Tar river
valley (delta created). 25 July 1997 – eruption of ash up to 40,000 feet with
pyroclastic flows.
VEI of 3. Eruptions characterised by
pyroclastic flows and tephra eruptions.
Most of Montserrat’s eruptions fall into
this category. Moderate explosiveness.
Responses:
Southern half of the island had to be evacuated as
they were covered in ash and lava. Following the first
eruption in 1995, all the others were predicted, due to
more technology and the ability to predict them. Due
to the dangers and the monitoring of the volcano, the
south of the island was marked as an exclusion zone, so
that people would be safe. Even if the monitoring
system was wrong, few people would be injured. People
still don’t live in the south of the island.
Why Do Earthquakes Happen?
Case Studies
• Tohuku Tsunami
• Haiti
Tohuku
Tectonic Setting:
Japan is located at the meeting point of 3 tectonic
Effects:
plates, The Eurasian, Pacific and Philippines. The
The tsunami waves that reached
heights of up to 40 metres in Miyako
boundary is to the East of the 4 main Japanese islands,
and, in the Sendai area of Honshu,
Hokkaido, Honshu, Shikoku and Kyushu. It is a
travelled up to 10 km (6 mi) inland.
convergent DESTRUCTIVE boundary, with faults
The island of Honshu was moved 2.4 m
running off the boundary. Japan gets 30% of the
east and shifted the Earth on its axis
world’s earthquakes every year, and there is 90mm of
by estimates of between 10 cm and
25 cm.
movement of the Pacific Plate under the Eurasian.
3 nuclear meltdowns at the Fukushima
Magnitude of 9.0. epicentre approximately 70 kilometres east of the Oshika
power plant. This caused contamination
Peninsula of Tōhoku and the hypocentre or FOCUS at an underwater depth of
of the sea and land, and force the
approximately 32 km (20 mi). 7.2 earthquake on the 9th of March, 2 days
evacuation of local residents.
The official death toll report
before the 8.9-9.0 magnitude earthquake of the 11th. There were also huge
confirmed 15,854 deaths, 26,992
numbers of large sized aftershocks, as big as magnitude 6.
injured and 3,155 people missing across
Responses:
twenty prefectures.
130,000 buildings totally collapsed and The warnings from the JMA also helped save lives. Many people did not react
quickly enough to the tsunami alert, and even if they did the 20 minutes or
another near 700,000 buildings
partially damaged.
less warning was insufficient for the people to escape.
Around 4.4 million households in north- Over 340,000 displaced people in the region needed catering for, and issues
eastern Japan were left without
included shortages of food, water, shelter, medicine and fuel for survivors.
electricity and 1.5 million without
Many countries sent search and rescue teams to help search for survivors.
water
NGOs and other Aid agencies helped too, with the Japanese Red Cross
The World Bank estimated cost was
US$235 billion, making it the most
reporting $1 billion in donations.
expensive natural disaster in world
Long Term – a bit too soon – clean up of the nuclear power stations.
history.
Haiti
Effects:
Buildings had not been built with earthquakes in
mind and were not life safe. 50% of buildings
collapsed due to cheap construction methodslack of corner braces, lack of steel in vertical
uprights etc. This meant that buildings
“pancaked” or the floors collapsed one on top of
the other.
Roads were also very badly damaged and
hindered aid efforts. The roads were littered
with cracks and fault lines.
316,000 people died and more than a million
people were made homeless, even in 2011 people
remained in make shift temporary homes.
Port Au Prince, where shanty towns and even the
presidential palace crumbled to dust.
3 million people in total were affected. The
government of Haïti also estimated that 250,000
residences and 30,000 commercial buildings had
collapsed or were severely damaged.
The port, other major roads and communications
link were damaged beyond repair.
The clothing industry, which accounts for twothirds of Haïti's exports, reported structural
damage at manufacturing facilities. It is
estimated that 1 in 5 jobs were lost as a result
of the quake.
Rubble from collapsed buildings blocked roads
and rail links.
Sea levels in local areas changed, with some
parts of the land sinking below the sea
Magnitude of 7.0. The
earthquake lasted 1
minute but caused
incredible damage. The
epicentre was 15 miles or
20km from the nation’s
capital, Port au Prince,
and the focus was very
shallow at only 13km
deep. Seismic waves
started at a fault line
that was 10km in length.
Tectonic Setting:
Haïti sits between the Caribbean and North
American plates, and is in a very tectonically active
zone of our planet. The Windward Islands of the
Caribbean are volcanic in origin and many active
volcanoes still exist there. The inner islands, Haïti
included, are known as the Leeward Islands and are
less volcanically active but do suffer from
Earthquakes. Haïti itself is on a strike slip fault that
runs off a destructive plate margin to the north of
the Island of Hispaniola, which Haïti shares with the
Dominican Republic.
Responses:
The EU gave $330 million and the World Bank waived the countries debt repayments for
5 years.
The Senegalese offered land in Senegal to any Haïtians who wanted it!
6 months after the quake, 98% of the rubble remained uncleared; some still blocking vital
access roads.
No. of people in relief camps of tents and tarps since the quake was 1.6 million, almost no
transitional housing had been built. Most of the camps - no electricity, running water, or
sewage disposal.
Between 23 major charities, $1.1 billion had been collected for Haïti for relief efforts,
only two percent of the money had been released.
One year after the earthquake 1 million people remained displaced.
The Dominican Republic offered support and accepted some refugees.
Medicines San Frontiers, a charity, tried to help casualties whilst the USA took charge of
trying to coordinate Aid distribution.