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Earth’s Layers • Based on Discover God’s Creation Chapter 2-3 by Rebecca Fraker Earth’s Layers See Discover God’s Creation (Red) 2-3 • Earthquake waves are used by geologists to study Earth’s interior. • Because earthquake waves travel at different speeds through different materials, they give us a glimpse of what the inside layers of Earth are made of. • Earth is designed somewhat like a baseball with different layers. These layers are called the: Crust Mantle Core The Crust • The crust is the thin outer layer of Earth that corresponds to the cover of a baseball. • The crust is made of dirt and rocks and is mostly covered by oceans. • The crust is 4-70 kilometers (3-40 miles) thick and is the thinnest of Earth’s layers. • Because we live on the crust, we know more about it than the other layers. • When you dig down through the crust, you find that the deeper you go, the warmer it gets. • This heat is caused by processes taking place deep within Earth. Miners feel this hear as they travel down very deep mine shafts. This heat causes oil from 2000 feet deep oil wells to more than 100 degrees! Plates • The crust is broken into large pieces called plates. The plates under the ocean are thinner than the plates that make up the continents. Mantle • In the early 1900s a Yugoslavian scientist discovered that earthquake waves changed speed as they traveled through different kinds of rock layers. • This discovery helped geologists learn about Earth’s mantle. The mantle is the thickest of the three layers. It is 1800 miles thick and makes up four-fifths of Earth’s volume. • Because of intense heat created by the weight of the crust and radioactive process, the mantle is made of melted rock called magma. • The lava of volcanoes comes from this magma. Lava is magma pushed up to the surface from the mantle. Core • Earth’s core is the innermost layer. It makes up a little less than one-fifth of the Earth’s volume. • The core has a diameter of about 4400 miles. • The outer core is thought to be made of molten iron. • Within the outer core lies the solid and very heavy inner core, the center of the Earth How deep have we gone? • The Kola Superdeep Borehole (KSDB) was a scientific drilling project of the USSR to drill into the Earth's crust. The drilling began on May 24, 1970 on the Kola Peninsula. A number of boreholes were made from a central branch. The deepest, SG-3, was completed in 1989, creating a hole 12.262 kilometers (seven miles) deep, the deepest hole ever made by humans. The Kola Borehole • The United states had a project called “Mohole”. Today, there are deep drilling projects around the world. • Research some of these projects. What they discovered was different than what was expected. • One project even started an “urban legend” that said that scientists had drilled into “hell” and let bat like demons out! (This was not true, of course. Can you prove it couldn’t be true from the Bible?)