THY DYNAMIC EARTH Geosphere, Atmosphere, Hydrosphere & Biosphere

1)Geosphere 2)Atmosphere 3)Hydrosphere 4)Biosphere

1) Geosphere Objectives  Describe the composition & structure of the Earth  Explain the main cause of earthquakes  Identify the relationship b/w volcanic eruptions & climate change  Describe how wind and water alter Earth’s surface

What is the Geosphere? (ROCK)  The solid part of Earth that consists of all rock, soils, and loose rock on Earth’s surface  Avg. distance through the center of Earth to the other side = 12,756 km (7,926 miles)

Composition of Earth  3 layers  Crust – thinnest layer, continents & ocean floor Type of rock: Silicon & Aluminum  Mantle – middle layer, 68% of Earth’s mass Type of rock: Iron & Magnesium  Core – innermost layer, center of the Earth Type of rock: Iron & Nickel Click on pic

Structure of Earth  5 layers 1. Lithosphere – outer layer & uppermost part of mantle, divided into tectonic plates 2. Asthenosphere – solid layer of the mantle made of rock that flows very slowly & allows tectonic plates to move on top of it 3. Mesosphere – “Middle sphere”, lower layer of mantle, very dense & solid 4. Outer Core – outer shell of Earth’s core, made of liquid nickel & iron, dense liquid core 5. Inner Core – dense & solid, ~ temp b/w 7232 o F – 9752 o F

Plate Tectonics  The lithosphere is divided into pieces called tectonic plates that glide across the underlying asthenosphere.

Plate Boundaries  3 Types 1. Convergent - oceanic plate is forced down into the mantle Example: Washington-Oregon coastline 2. Divergent – extensional forces stretch the lithosphere producing a deep fissure Ex: Mid-Atlantic Ridge 3. Transform – formed b/w 2 different plates that move away from the spreading center Ex: San Andreas Fault

Now you try! Milky Way Activity  Represent different faults/boundaries that we just discussed  Turn in worksheet at end of class.

1) Geosphere Objectives  Describe the composition & structure of the Earth  Explain the main cause of earthquakes  Identify the relationship b/w volcanic eruptions & climate change  Describe how wind and water alter Earth’s surface

Earthquakes  How an earthquake is formed?  A fault is a break in Earth’s crust along which blocks of the crust slide relative to one another  Rocks under pressure suddenly slip along a fault & set off vibrations  Vibrations of Earth’s crust caused by slippage along a fault are earthquakes

Earthquakes cont.  Quantify the amount of energy released by an earthquake  The measure of the E released – magnitude  Smallest magnitude felt = 2.0  Largest magnitude felt = 9.5  Widespread damage = 7.0+  To increase one whole #, the earthquake must be 30x stronger Richter Scale

Earthquakes cont.  Take place/near tectonic plates  San Andreas fault (entire length of California)  1886, ~7.0 Earthquake shook Charleston, SC Earthquakes Occur?

Volcanoes  Is a mountain built when magna (melted rock) rises from Earth’s interior to its surface  Magma reaches surface = lava  Located near tectonic plates boundaries  Occur on land or under the sea (above ocean surface then islands are formed)  World’s most active volcanoes on land are surrounding the Pacific Ocean.

Local Effects of Volcanic Eruptions  Erupts when the pressure of magma inside becomes so great that is blows open the solid surface of the volcano  Clouds of ash, dust, & gases can flow down the slope of a volcano at speeds up to 100mi/h & sear everything in it’s path  Buildings collapse due to weight of ash, bury crops, & damage engines  Breathing difficulties

Pompeii Images In 79 A.D. Mount Vesuvius, a volcano near the Bay of Naples in Italy erupted buried the city of Pompeii

World Effects of Volcanic Eruptions  Change Earth’s climate for several years  Reduce the amount of sunlight  Lower the surface temperature

Weathering & Erosion  Pick up a sheet of white paper  Divide the paper into 3’s (like an envelope)  On the top 1/3 DRAW/CREATE your own picture of a river (15 minutes)

Weathering & Erosion  Earth’s surface is continually changing by:  Wind  Running water  Moving rocks  Chemical Weathering: wears down rocks making them smoother as time passes  Erosion: transports the materials elsewhere

Erosion  Rivers & Oceans  Waves erode coastlines  Rivers carve deep gorges in the landscape  Colorado River – Grand Canyon  Wind blows soil away very quickly  Beaches & deserts  No plants in loose soil  Soft rocks erode faster than hard rocks Water ErosionWind Erosion

Erosion Landforms  Water erosion  Wind erosion