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 MAKE SURE NOTEBOOKS ARE SET-UP before starting!

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 Process used in nuclear power plants Nuclear Fusion – nuclei combine The way in which the Sun produces energy These nuclear reactions are different than combustion. Combustion = a chemical reaction where energy is released when one substance is changed into another. Wood turns into charcoal/ash when it burns. Nuclear = a reaction on an atomic level where atoms are either split apart or fused together

Electromagnetic Spectrum Most energy = smallest wavelength (have kids wave hand, short fast wave = gamma rays; slow, wide wave = radio waves) Red Mice In Venice Usually eXit Gently

Filtering the EM Spectrum Not every wavelength emitted by stars (including our Sun) reaches Earth’s surface - Only the larger wavelengths of UV light, visible light, and smaller wavelengths of infrared and radio waves make it to Earth’s surface - All other wavelengths are blocked at different heights in our atmosphere

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 Nuclei collide in the core releasing a photon Photon energy is transferred from one particle to the next through conduction 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 WEATHERING and EROSION HEAT and PRESSURE COMPACTION and CEMENTATION MELTING and COOLING Materials 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 Pangaea!!!! 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!!!! Pangaea = 240 million years ago Pannotia = 600 million years ago Rodinia = 1 billion years ago

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 DIVERGENT TRANSFORM 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 Aftershock 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 Body Waves Surface Wave P wave: push/pull wave through rocks (1st) S Wave: shake particles at right angles (2nd) Surface Wave Travel along the Earth’s surface

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 MMS = Moment magnitude scale which replaced the Richter scale in the 1970s

The Scales Richter Scale Mercalli 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 Cinder Cones Composite Cones 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 Telphra = bits of rock or solidified lava dropped from the air after an explosive eruption

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 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 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: 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: Creates soil horizons parent material, topography, climate, organisms, time Creates soil horizons

Topography

Climate Cool, dry, sparse vegetation Warm, wet, abundant 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 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! Mention Hurricane Hugo…

Geohazard Protection

Family Disaster Preparedness Plan Due September 18th Unit 1 Project Family Disaster Preparedness Plan Due September 18th