Transcript File - Ms Hicks` Classes

Natural Disasters
Earthquakes and Volcanoes
Ring of Fire
• The “Ring of Fire” is a series of tectonic plate
boundaries around the Pacific Ocean.
• 75% of the world’s volcanoes and 90% of the
world’s earthquakes occur here
VOLCANOES
What is a Volcano?
• An opening in the
earth’s crust where
magma (molten rock)
flows from the mantle
to the surface
• Volcanoes create new
land when molten rock
reaches the surface,
cools and hardens into
solid rock
• This can sometimes
cause fast-moving
landslides of boiling
mud
Divergent Zones
• Divergent zones –
where two plates are
moving away from each
other (Katla volcano in
Iceland)
Subduction Zones
• Subduction zones –
where two plates are
crashing into each other
(Kyushu volcano in
Japan)
Volcanoes in North America
• There are active volcanoes along the pacific coast of Canada
(British Columbia) and USA at the Pacific Plate Subduction Zone
Mount St Helens before it erupted
in 1980
Mount St Helens after it erupted in
1980
How do volcanoes DESTROY
land and life?
How do volcanoes CREATE
land and life?
Destroys plants/ animals
Plants can grown in volcanic
soil
Landslides / lava flows
Kill people (burning,
smoke/gas)
Lava cools into new rock = new
land
Opportunity for new plants to
Land gets covered by new rock, grow
ash, lava
Paricutin, Mexico
• A crack opened up in a farmer’s cornfield in 1943
• Ash and stone poured out, and it grew quickly –
it reached 5 stories tall in one month
• After 1 year it was over 1,100 feet tall
• It kept erupting for 8 years
3 TYPES OF VOLCANOES
1) Composite Volcano
• Also known as strato volcanoes
• Steep sided cones formed from
layers of ash and lava flows.
• It can erupt magma or a
pyroclastic flow (a superheated
mixture of hot steam, ash, rock
and dust that can travel down a
volcano at very high speeds with
temperatures over 400 degrees
celsius).
• When composite volcanoes erupt
they are explosive and pose a
threat to nearby life and property.
• Usually found at destructive plate
margins.
• Examples of composite volcanoes
include Mount Fuji (Japan),
Mount St Helens (USA) and
Mount Pinatubo (Philippines).
2) Shield Volcanoes
• Shield volcanoes are low with
gently sloping sides and are
formed from layers of lava.
• Eruptions are typically nonexplosive. Shield volcanoes
produce fast flowing lava that
can flow for many miles.
• Eruptions tend to be frequent
but relatively gentle. Although
these eruptions destroy
property, death or injury to
humans rarely occurs.
• Usually found at constructive
boundaries and sometimes at
volcanic hotspots.
• Examples: Mount Kilauea and
Maunaloa on Hawaii.
3) Dome Volcano
• Acid lava is much thicker
than the lava from shield
volcanoes.
• Dome volcanoes have much
steeper sides than shield
volcanoes. This is because
the lava is thick and sticky. It
cannot flow very far before
it cools and hardens.
• An example is Puy de Dome
in the Auvergne region of
France which last erupted
over 1 million years ago.
What is a Caldera?
• A caldera is a cauldronlike volcanic feature
usually formed by the
collapse of land
following a volcanic
eruption.
Mount Nyiragongo
Mount Nyiragongo
• An active volcano in the
Democratic Republic of
Congo
• The city of Goma (pop:
1 million) only lies 1318 km south of the
volcano
• It erupted in 2002, most
people were evacuated
in time
• But the lava destroyed
more than 40% of the
city
Mt Vesuvius
Mt Vesuvius
• Mount Vesuvius is best
known for its eruption in AD
79 that led to the burying
and destruction of the
Roman cities of Pompeii and
Herculaneum.
• An estimated 16,000 people
died
• Vesuvius has erupted many
times since and is the only
volcano on the European
mainland to have erupted
within the last hundred
years.
• Today, it is regarded as one
of the most dangerous
volcanoes in the world
because of the population
of 3,000,000 people living
nearby and its tendency
towards explosive
eruptions
Yellowstone Supervolcano
• Yellowstone National
Park is famous for its
hot springs and its
geysers, like Old Faithful
• There is an immense
supervolcano there, it is
one of the largest in the
world
If the Yellowstone Supervolcano
erupted...
EARTHQUAKES
The Richter Scale
• The Richter magnitude
scale assigns a
magnitude number to
measure the energy
released by an
earthquake.
• It goes 1-10
• An earthquake that
registers 5.0 on the
Richter scale is 10 times
stronger than that of an
earthquake that
registered 4.0
• A 3.0 earthquake is often
felt by people, but very
rarely causes damage.
Shaking of indoor objects
can be noticeable.
• A 8.0 earthquake would
cause major damage to
buildings. Will cause
moderate to heavy
damage to sturdy or
earthquake-resistant
buildings. Damaging in
large areas.
2010 Haiti Earthquake
• It measured 7.0 in
magnitude
• Deaths = 100,000200,000
• The poverty and poor
housing conditions
exacerbated the death
toll
2004 Indian Ocean earthquake &
tsunami
• An over 9.0 magnitude
quake hit the ocean
near Indonesia
• Triggered tsunamis that
killed over 230,000
people in 14 countries
• 3rd strongest
earthquake measured
with modern
equipment
The next California earthquake?
• According to a new study,
there is so much built-up
tension under the San
Andreas fault, major
earthquakes could be
coming soon.
• This could affect millions
living in the San Francisco
Bay Area, as some of the
fault lines are located
underneath the heart of
the area’s infrastructure.