Interior of the Earth Info The Earth’s Surface Volcanoes Earthquakes Interior of the Earth Info Rock Cycle History of the Earth

Rockin’ Rock Cycle

Igneous Rocks Igneous rocks means “rocks of fire” Igneous rocks form from magma or lava Magma can cool beneath the surface called intrusive. Magma can cool on the surface called extrusive.

Intrusive Igneous Rocks: Slow cooling Larger crystals will form Called Coarse-grained Igneous Rock Example: granite Extrusive Igneous Rocks: Rapid cooling Small crystals will form Called Fine-grained Igneous Rock Example: basalt, rhyolite

Porphyritic Igneous Rock * Has large and small crystals *Cools slowly at first and then more rapidly (intrusive & extrusive) Example: some forms of granite Glassy Igneous Rock *Highly viscous magma cools very quickly (extrusive) Magma has a small percentage of dissolved gasses Example: obsidian

Vescular Igneous Rock *Highly viscous magma cools quickly (Extrusive) Magma has a large percentage of dissolved gasses *Gas bubbles get trapped in the rock producing holes (vesicles) Example: pumice

Sedimentary Rocks Rock can break down into small pieces or fragments due to wind, water and movement of the crust. This is sediment Sediment is transported by wind, water or ice to a new location. Sediment is then compacted or cemented together to create sedimentary rock. The layering of the rock is called stratification

Clastic Sedimentary Rock Water causes this sedimentary rocks to form *Eroded sediment is carried down rivers and streams until the sediment settles out. *Lithification takes place – compaction and cementation Examples: Conglomerate Sandstone Shale

Chemical Sedimentary Rock *Chemical reactions occur in water that produces precipitates or solid compounds These solids will settle at the bottom of the lake or river bed. Examples: Halite (rock salt) Gypsum

Organic Sedimentary Rock *Forms from remains of plants and animals including bones and shells Examples: limestone coal

Metamorphic Rocks Occurs because of heat and pressure applied to existing rocks. Occurs deep in the Earth’s crust or when magma comes in contact with the rock Examples of metamorphic change: Shale becomes slate Limestone becomes marble Granite becomes gneiss Sandstone becomes quartzite

Foliated Metamorphic Rock *Bands of color or layers are apparent Example: gneiss Non-foliated Metamorphic Rock *no layers are apparent Example: marble

The Rock Cycle

Interior of the Earth

Volcanoes A) Related to Plate Tectonics 1) Volcanoes mostly occur at plate boundaries 2) Most volcanoes are a result of subduction

B) Reasons for Volcanic Activity 1) Subduction Oceanic crust to continental crust causing a trench and volcanic mountains on the continent. Oceanic crust to oceanic crust causing a trench and an island arc.

2. Mid-Ocean Ridges a) As plates move apart, magma rises creating a rift zone b) Most of these volcanic eruptions take place under water. 3. Hot Spots a) Columns of solid, hot material that rises up into the lithosphere b) The plate above the hot spot will continue to move and new sites for volcanoes are created.

2) Africa’s Rift Valley – African plate dividing into two plates C) Active Volcano Regions 1) Pacific Ring of Fire – outlines the plates located under the Pacific Ocean 2) Africa’s Rift Valley – African plate dividing into two plates 3) Iceland – Part of Mid-Atlantic ridge and a hot spot 4) Hawaii – Hot spot

Earthquakes A) Related to Plate Tectonics 1) Earthquakes mostly occur along plate boundaries 2) At convergent boundaries, the overriding plate scrapes on top the subducting plate causing earthquakes. 3) At divergent boundaries, the spreading movement of the plates cause earthquakes 4) At transform boundaries, the release of stress from the opposite movement of the plates causes earthquakes.

B) Anatomy of Earthquakes 1) Focus: location within the Earth where the first motion of the earthquake takes place 2) Epicenter: the point of the Earth’s surface directly above the focus

C) Elastic Rebound Theory 1) Rocks bend until the strength of the rock is exceeded. Rupture occurs and rocks shift to an undeformed shape 2) Roads, fences, powerlines, railroads, etc. will be shifted when elastic rebound takes place during an earthquake

D) Seismic Waves 1) Seismic waves are the vibrations from the energy release.

2) Body Waves: move through Earth’s interior a) P – waves 1) compression waves 2) travel through solids, liquids and gases 3) fastest moving waves b) S – waves 1) move particles of rock side to side 2) travel only through solid materials 3) second-fastest waves

3) Surface Waves a) These waves travel along the surface of the Earth. b) Rayleigh waves move in a rolling motion. c) Love waves move through rock in a side-to-side motion.

E) Measuring Earthquakes 1) Seismograph: instrument that measures the vibrations during an earthquake. 2) Magnitude a) a measurement of the amount of ground motion (the strength) on an earthquake. b) measured on the Richter scale or on the Moment Magnitude scale c) the larger the number on the above scales, the stronger the earthquake

3) Intensity a) measure the amount of damage caused by an earthquake b) measured on the Modified Mercalli Intensity scale c) the intensity of the earthquake depends on the magnitude, distance from epicenter, earthquake’s duration, and geology.

Earthquakes/Volcanoes Effect Humans Damage and loss of property Loss of lives Economic loss of property and life style Loss of plant and animal habitat Need for economic relief to rebuild lives (government subsides, donations)

Interior of the Earth 1) S-waves can not pass through liquids, therefore the outer core has been determined to be liquid 2) P-waves travel through solids, liquids and gases. The speed and the direction of the P-waves can change as the waves passes through each layer of the earth. It has been determined that the inner core is a very dense solid.

Oceanic/Continental Crust 1) Oceanic Crust a) Denser b) Younger c) Made of Basalt 2) Continental Crust a) Less dense b) Older c) Made of granite