The Earth Earthquakes Earthquakes are the shaking, rolling or sudden shock of the earth’s surface. Earthquakes happen along "fault lines" in the earth’s crust. Earthquakes can be felt over large areas although they usually last less than one minute. Click on the link below for more information. (List five facts from the Fact and Fiction section). Volcanoes A volcano is a mountain that opens downward to a pool of molten rock below the surface of the earth. When pressure builds up, eruptions occur. Gases and rock shoot up through the opening and spill over or fill the air with lava fragments. Click on the link below for more information. (List five facts from the Volcano Facts section). Types of Rock Rocks are the most common material on Earth. They are naturally occurring aggregates of one or more minerals. Click on the link below for more information. (List the three types of rock and explain how they are formed). Weathering Weathering takes place as rocks are broken down into progressively smaller pieces. There are three types of weathering: mechanical, chemical, and biotic. Click on the link below for more information. (Describe the three types of weathering and provide one example for each). Erosion Webster's defines erode as, "To eat into or away by slow destruction of substance." Click on the link below for more information. (Define erosion in your own words. List three land forms created by erosion). Constructive Processes (Deposition) Constructive processes help the Earth. Click on the link below to discover how beaches, sand dunes, and deltas are formed. (Describe how each are formed. Name a delta found in the United States.).