Transcript Unit 1 Notes

Unit 1 Notes
The Geosphere
Unit Objectives
 EEn.1.1.3 Explain how the sun produces energy which is
transferred to the Earth by radiation.
 EEn.2.1.1 Explain how the rock cycle, plate tectonics, volcanoes,
and earthquakes impact the lithosphere.
 EEn.2.1.2 Predict the locations of volcanoes, earthquakes, and
faults based on information contained in a variety of maps.
 EEn.2.1.3 Explain how natural actions such as weathering,
erosion (wind, water and gravity), and soil formation affect
Earth’s surface.
 EEn.2.1.4 Explain the probability of and preparation for
geohazards such as landslides, avalanches, earthquakes and
volcanoes in a particular area based on available data
EEn.1.1.3
How Stars Produce Energy
Combustion vs Burning
• Burning is a type of combustion where flames
can be seen
– Most of the energy from burning is converted into
light energy
• Combustion is a reaction that takes place
without flames so there is more energy in the
form of heat produced
Nuclear Fission vs Nuclear Fusion
• Nuclear Fission – nuclei
split
• Nuclear Fusion – nuclei
combine
• Process used in nuclear
• The way in which the Sun
produces energy
power plants
Electromagnetic Spectrum
Filtering the EM Spectrum
• Not every wavelength emitted by stars
(including our Sun) reaches Earth’s surface
Energy Transfer
• Conduction – energy is
transferred when particles
touch each other
• Convection – energy is
transferred through fluids
(liquids and gasses)
• Radiation – energy is
transferred by
electromagnetic waves
Energy Transfer in Stars
1. Nuclei collide in the core releasing a photon
2. Photon energy is transferred from one particle to the
next through conduction
3. Energy rises to the surface by convection
4.
Energy is
then
radiated
out into
space
Solar Forces in Balance
• Stars are held together
by gravity.
• Gravity tries to
compress everything to
the center.
• Thermal and radiation
pressure try to expand
the star layers outward
to infinity.
EEn.2.1.1
The Rock Cycle, Plate Tectonics,
Volcanoes and Earthquakes
The Rock Cycle
Forces & Materials in the
Rock Cycle
• Forces
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WEATHERING and EROSION
HEAT and PRESSURE
COMPACTION and CEMENTATION
MELTING and COOLING
• Materials
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IGNEOUS ROCK
SEDIMENTARY ROCK
METAMORPHIC ROCK
MAGMA/LAVA
SEDIMENTS
ROCK CYCLE
• Energy is required for rocks to change from
one type to the next
• Sedimentary = external energy from the Sun
to drive weathering and erosion
• Igneous & Metamorphic = energy in the form
of heat from the Earth’s core
Plate Tectonics
Earth’s Layers
• Crust is thin and rocky
– Oceanic = younger rocks
– Continental = older rocks
• Mantle 82% of Earth’s volume is
found here
– Lithosphere – a strong layer under
the upper mantle
– Asthenosphere – a softer layer under
the lithosphere
• Core
– Outer – liquid due to extreme heat
– Inner – solid due to intense pressure
• Compostion of layers due to
density of materials;
– heavier elements in the core
– lightest elements in the crust
Continental Drift
• Theory prior to plate tectonics
• Proposed by German scientist Alfred
Wegener in 1915
• States that the continents had once been
joined to form a single supercontinent
• Pangaea!!!!
Evidence
• The continental
puzzle
• Matching fossils
• Similar rock types
and structures
• Similar ancient
climates
A New Theory
• Wegener’s theory was replaced in the 1950s and 60s
by plate tectonics
• Takes in to account tectonic activity and mantle
convection
Causes of Plate
Tectonics
• Mantle Convection
– Transfer of thermal energy by the movement of
heated matter in the mantle
• Rising mantle – divergent boundary
• Falling mantle- convergent boundary
– Push and Pull
• Ridge push
• Slab pull
Earth’s Major Plates
• The lithosphere is
divided into tectonic
plates
• These plates move and
continually change
shape and size
Types of Boundaries
• CONVERGENT
– Where 2 tectonic plates are moving together
• Creates a subduction zone
– Trenches, island arcs and folded mountains
• DIVERGENT
– Where 2 tectonic plates are moving apart
– Volcanism, earthquakes and high heat flow
• TRANSFORM
– Where 2 tectonic plates are sliding horizontally past
one another
– Long faults and shallow earthquakes
Convergent = Destroy
oceanic-continental
continental-continental
oceanic-oceanic
• Form either a subduction zone or a continental
collision
• Earthquakes and volcanoes are common
• Oceanic-Continental = Cascade Mountain Range
• Continental-Continental = Himalayas
• Oceanic-Oceanic = Mariana Trench, Japan, Aleutian
Islands
Divergent = Create
• Black Hills, SD
• East African Rift
Valley
• Red Sea
• Mid-Atlantic Ridge
– Seafloor spreading
Transform = Conserve
 San Andreas Fault in California most famous
Earthquakes
https://www.youtube.com/watch?v=_gE0UnyA2kI
• Earthquakes occur because of the forces of
plate tectonics
– Place where two tectonic plates meet form a
boundary; faults are found at these boundaries
• Earthquake waves can travel around the world
through the different layers of the Earth
• There are two parts – the focus and the
epicenter
Two Parts of an Earthquake
• Focus: Point within the
Earth where the
Earthquake starts.
• Epicenter: On the surface
above the epicenter.
Types of Faults
Reverse Fault/Thrust Fault = Convergent Boundary
Normal Fault = Divergent Boundary
Strike-Slip Fault = Transform Boundary
Two Types of Shocks
• Foreshock
– Before an earthquake
– Can happen years/days
before an earthquake
• Aftershock
– Follows a major
earthquake (usually
smaller than original
quake
How do we measure waves?
Seismograph
Two Types of Waves
• Surface Wave
– Travel along the Earth’s
surface
• Body Waves
– P wave: push/pull wave
through rocks (1st)
– S Wave: shake particles
at right angles (2nd)
P and S Waves
Finding the Center of an Earthquake
• Use measurements from three seismic
stations
• Data is used with a distance – time graph to
triangulate the earthquake’s origin
Measuring Destructive Force
• Magnitude (MMS)
– amount of energy released
at the focus
• Intensity (Mercalli Scale)
– Amount of shaking
– Measured at a specific
location
The Scales
• Richter Scale
– Based on the amplitude
(height) of the largest
wave
– Replaced by Moment
Magnitude Scale (MMS)
• Mercalli Scale
– Amount of displacement
from the fault
Types of Destruction
Seismic Vibrations
Landslides
Tsunamis
Fires
Volcanoes
Factors Affecting Eruptions
• Primary Factors
– Magma composition
• More silica = thicker lava
• More iron/magnesium =
thinner lava
– Magma temperature
– Amount of dissolved gases
– Viscosity – a substance’s
resistance to flow
Where Do Volcanoes Form?
• Divergent boundaries
– Magma chambers are close to the surface due
to the plates moving apart
• Convergent boundaries
– Subducted plate melts and forms magma
chambers under the volcano
Types of Volcanoes
• Shield Volcanoes
– Largest type
– Form at divergent
boundaries
• Cinder Cones
– Small cones of telphra
– Form near shield volcanoes
• Composite Cones
– Made of alternating layers
of lava and telphra
– Form at convergent
boundaries
Other Volcanic Landforms
Calderas – a large
depression in a volcano
• Necks & Pipes – How
magma gets through
the volcano
Lava Plateaus
Mt. Saint Helens Eruption
May 18, 1980
https://www.youtube.com/watch?v=SJA27Bp1q58
A Supervolcano?!?!?
Where could it be?
Yellowstone
National Park
Wyoming,
United States
https://www.youtube.com/watch?v=DS3RA7NdVKE
Een.2.1.2
Predicting Earthquakes and
Volcanoes from Maps
Predicting Earthquakes
• Short range – very difficult to
determine exactly when and
where an earthquake will
happen, but seismographs give
clues
• Long range forecasts predict
whether an earthquake is likely
to occur in a given area within
30 to 100 years.
• Because earthquakes and volcanoes occur at
plate boundaries, areas along faults are most
likely to experience these hazards
EEn2.1.3
Weathering, Erosion and Soil
Formation
Mechanical vs Chemical Weathering
Mechanical
•Occurs when physical
forces break down rocks –
temperature & pressure
•Three process:
– 1.) Frost Wedging
– 2.) Unloading
– 3.) Biological Activity
Chemical
• Transformation of a rock
from one form to another
– Water (hydrolysis), oxygen
(oxidation), carbon dioxide
(carbonic acid), acid rain
• Water: A major factor!
Mechanical Weathering
Chemical Weathering
Rate of Weathering
• Three factors are:
1.) Rock Characteristics: the physical way a rock looks
2.) Climate: Temperature and moisture
3.) Differential Weathering: Different parts of rock
mass weather at different rates.
Just a little soil information
• An important product of weathering
• Supports growth of plants
• Four major components:
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1.) Mineral Matter: about 45% of the matter in soil
2.) Organic Matter: 5% (decayed things)
3.) Water: 25% water
4.) Air: 25% air
How Soil is Formed
• Requires 5 things:
– parent material, topography, climate, organisms, time
• Creates soil horizons
Topography
Climate
• Cool, dry, sparse vegetation
– Predominantly physical weathering
• Warm, wet, abundant vegetation
– Increased chemical weathering
The Soil Profile
• Soil varies in
texture,
composition,
structure, and color
at different levels.
– A Horizon – Topsoil
– B Horizon – Subsoil
– C Horizon –
Bottom true to the
parent material
– R Horizon Bedrock
Erosion
• Movement of weathered material from one
location to another
• Rates of Erosion:
– More plants, grass, and trees helps to hold the soil in
place.
– Human activity that removes these things help to
speed up erosion.
EEn2.1.4
Mass Movement and Geohazards
Mass Movement
What it is and its Triggers
• The transfer of rock and soil down slope due to
gravity and caused by weathering and erosion
Water
Saturating surfaces
creating mudflows
Over-steepened Slopes Water cuts under the
bank of a river
Removal of Vegetation
Taking away plants and
roots
Earthquakes
Shake loose soil
creating a landslide
Types of Mass Movement
• Based on the kind of material, how it moves and the
speed of the movement.
• Rockfall = rocks fall from a steep slope
• Slides = land sides down suddenly
– High mountain areas
• Slumps = downward movement of a block of material
in a curved surface
• Creep = the slowest form of movement
• Flows = mass amounts of movement
– 2 types:
• Mudflow – Moves quickly
• Earthflow – Moves slowly
Geohazards
Geohazards
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Landslides
Mudslides
Avalanches
Falling rock
Volcanoes
Earthquakes
Floods
Geohazard Protections
• It is impossible to prevent geohazards or to
know exactly where and when they will occur
• Can use levees, damns, wire netting, breaks
and special building codes to help limit
damage and save lives
• Having a disaster preparedness plan in place
is extremely important for EVERYONE!
Geohazard Protection
Unit 1 Project
Family Disaster
Preparedness Plan