The study of the forces that change the Earth’s surface. What is Geology? The study of the forces that change the Earth’s surface.

These forces can either build-up or wear-down the Earth.

What are Constructive forces? Forces that shape the Earth’s surface by building up mountains and landmasses. Example: Volcanic Eruption adds new landmass.

What are Destructive forces? Forces that wear away mountains and every other feature on the Earth’s surface. Example: Weathering & Erosion due to wind or water.

What are the main layers that make up the Earth’s interior? 1. Crust 2. Mantle 3. Outer Core 4. Inner Core

Describe the Crust. It is the layer of the Earth that forms the outer skin. It includes both continental land and the ocean floor. Anywhere from 7-75 km thick.

Oceanic Crust is crust beneath the ocean & is made up from… BASALT

http://www.pitt.edu/~cejones/GeoImages/2IgneousRocks/IgneousCompositions/3Basalt/BasaltSmallVesicOlPheno.jpg http://www.explorevolcanoes.com/volcanoimages/spreading%20ridge%20Press%20and%20Siever.jpg

Continental Crust is crust that forms above the ocean & is made up mostly from … GRANITE

http://www.earth.ox.ac.uk/~oesis/field/medium/granite1.jpg http://images.google.com/imgres?imgurl=http://www.beg.utexas.edu/mainweb/publications/graphics/granite-400.jpg&imgrefurl=http://www.beg.utexas.edu/mainweb/publications/graphics/granite.htm&usg=__0de5K-fYX3ZSELLMQs78BEQCxqI=&h=300&w=400&sz=78&hl=en&start=1&um=1&itbs=1&tbnid=KHAn81O-WrYHiM:&tbnh=93&tbnw=124&prev=/images%3Fq%3Dgranite%26hl%3Den%26sa%3DN%26um%3D1

Density of Earth’s Crust Continental crust has an average density of about 2.7 g/cm3. Oceanic crust has an average density of about 3.0 g/cm3. Which type of crust is more dense?

Describe the Mantle. A layer of hot rock material that is located beneath the crust. Over 82% of Earth’s volume at about 2900 km thick. Is divided into several layers. Upper mantle which is made up of the lithosphere & asthenosphere Lower mantle which is called the mesophere

What is the Lithosphere? The layer of rigid rock that includes all of the Crust and the upper portion of the Mantle. It’s about 100 km thick

What is the Asthenosphere? A layer of solid rock that behaves like a fluid (it flows and moves like a liquid). This layer is found in the Mantle beneath the lithosphere. The lithosphere floats on top of the asthenosphere.

The Earth’s Core is composed of what? The inner core and the outer core together make up the structure of the Earth’s core. Both the outer and inner cores are composed of iron & nickel. The outer core is liquid (molten) metal and the inner core is solid metal

How do geologists know the internal structure of the Earth? Because the actual interior of the Earth cannot be seen, geologists have relied on observations from indirect evidence. Indirect evidence is evidence that you get without actually seeing or touching the object you are studying.

They are waves of energy generated by earthquakes. What are seismic waves? They are waves of energy generated by earthquakes. There are two types: P waves & S waves

How are seismic waves used to determine the Earth’s interior? Speed of seismic waves change as they pass through the Earth. Differences in each layer such as density and state of matter, cause these waves to behave differently. By carefully studying these waves geologist are able to create a picture of the Earth’s interior.