Transcript The Restless Earth - Langley School, Solihull

The Restless Earth
Revision Resource for volcanoes,
earthquakes, fold mountains.
Why do these things happen?
Convection Currents
drive everything
How does this impact on the planet?
1. Destructive Plate Margins
Give examples of some these.
2. Constructive Plate Margins
Give examples of some these.
3. Conservative Plate Margins
Give examples of some these.
Landforms at Plate Boundaries
Fold Mountains and Ocean Trenches
When fold mountains are formed
various the rock get folded in a variety
of ways. These have specific names
which you have to learn for the exam.
Anticline - the upfolds of folded rock
Syncline - the downfolds of folded rock
Give examples of some these. What is impact of
fold mountains on population sizes?
Case Study 1: Human Activity in Fold
Mountain Areas - THE ALPS
Transhumance Farming
Low population – physical reasons.
Most activity concentrated on valley floors.
Range of problems for settlement, transport,
etc.
Landforms at Plate Boundaries
Volcanoes
Shield Volcano
At constructive margins. Basic
lava (low silicon content). Pours
out easy. Low violence, but
regular. E.g. Mauno Lao in
Hawaii.
Composite Volcano
At destructive margins. Acid
Lava .Greater heat and
pressure. Layers of lava and
ash. Irregular eruptions. Violent.
E.g. Mount Etna in Italy
You must be clear about the differences between the two.
Landforms at Plate Boundaries
Supervolcanoes
Yellowstone
Yellowstone is fueled by a
Hotspot. A hotspot is simply a
location at the earths crust
where magma from the mantle
releases heat and in turn shapes
the crust.
The Yellowstone Hotspots are
the result of approximately 17
eruptions. The most recent
eruptions Lava Creek, Mesa
Falls, and Huckleberry Ridge
occurred approximately 600,000
years, 1.3 million years, and 2.1
million years ago respectively.
The devestation has been seen
historically to cover half of the
USA.
Effects of Volcanoes
Try to remember Primary (injuries, buildings destroyed, roads ruined, electricity
down) and Secondary (no water or food, disease, rebuilding costs, social
breakdown) effects of Volcanoes
Case Study 2: Volcano in MEDC – Mount Etna, Italy (2001)
Location and Background Facts
Eruption occurred in Sicily an island in Italy in July 2001
Located on a destructive plate boundary between the Eurasian & African plate.
Composite cone volcano.
Why did it happen?
Eurasian plate is subducted under the African plate.
Friction causes the crust to melt and this forces it’s way up into the magma
chamber.
Pressure builds up in the magma chamber and eventually is released as an
explosion.
This causes gas & steam to escape, volcanic bombs, lava & pyroclastic flows.
Social Effects
Holiday villas damaged
Towns and villages destroyed
Eg: Catania
People died
Environmental Effects
Vegetation destroyed
Animals killed
Economic Effects
Orange groves & vineyards wiped out in
Zaffarena
Roads destroyed so hard to access area
Ski areas ruined
Farms destroyed & covered in ash
Airport forced to close due to ash on the
runway.
Case Study 3: Volcano in LEDC – Montserrat (1995 / 1997)
Montserrat is a small island in the
Caribbean and is a British colony.
During this time, Montserrat was
devastated by pyroclastic flows.
The small population of the island
(11,000 people) was evacuated in
1995 to the north of Montserrat as
well as to neighbouring islands and
the UK.
Despite the evacuations, 19 people
were killed by the eruptions as a
small group of people chose to stay
behind to watch over their crops.
Volcanic eruptions and lahars have
destroyed large areas of Montserrat.
The capital, Plymouth, has been
covered in layers of ash and mud.
Many homes and buildings have
been destroyed, including the only
hospital, the airport and many roads.
There are still some problems
attracting investment to the region.
Features of Volcano
Lahar
Features of Volcano
Ash Cloud / Volcanic Bombs
Features of Volcano
Pyroclastic Flow
Why do Earthquakes happen?
(focus)
San Andreas Fault, USA.
Effects of Earthquakes
Effects of Earthquakes (cont)
Case Study 4: Earthquakes in MEDC – Kobe, Japan (1995)
6000+ dead
Effects
Case Study 5: Earthquakes in LEDC – Kashmir, Pakistan
(2005)
87,000 dead
Measuring Earthquakes
Mercalli is a descriptive scale based on damage.
Richter is logarithmic based on readings from a
Seismograph. E.g 7 is 10 times stronger than 6.
Predicting and Preventing Earthquake Damage
Tsunami
Case Study 6: Indian Ocean Tsunami (2004)
230,000 dead