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E ARTH’ S I NTERIOR S ECTION 1 EARTH’S INTERIOR We never have been able to visually see into the center of the Earth. The largest mine is in South Africa and is about 3.8 kilometers (2.4 miles) deep. EARTH’S INTERIOR Scientists use indirect observation to observe the Earth’s interior. Scientists know about the interior of the Earth from waves produced by earthquakes. Seismic waves – waves produced by earthquakes. EARTH’S INTERIOR The speed of the seismic waves tell scientists about the structure of the Earth. EARTH’S INTERIOR Diagram From: revisionworld.co.uk EARTH’S INTERIOR To begin a journey to the center of the Earth, you would need to travel through solid rock. Temperatures and pressures would change as you travel towards the center. EARTH’S INTERIOR Temperatures At first, the temperature around the surface is cool. Then temperatures increase rapidly for several miles and then increase slowly after that. For every 40 meters you travel inward, the temperature rises 1ºC (33.8ºF). EARTH’S INTERIOR Pressure The deeper you travel into the Earth, the greater the pressure. Pressure – the force pushing on a surface or area EARTH’S INTERIOR You will travel through several layers as you travel through the Earth. The Earth is made up of three main chemical layers. crust mantle core EARTH’S INTERIOR Diagram From: faculty.weber.edu EARTH’S INTERIOR Each layer has its own conditions and materials. Diagram From: eoearth.org EARTH’S INTERIOR Crust – a layer of rock that forms Earth’s outer skin Very thin layer of the Earth. Includes both the dry land and the ocean floor. Thickest under high mountains and thinnest under the ocean. EARTH’S INTERIOR Oceanic crust is made of dense materials. Continental crust is made of less dense materials. 5-40 km thick Made of oxygen, silicon, aluminum, calcium, iron, sodium, potassium, and magnesium EARTH’S INTERIOR EARTH’S INTERIOR EARTH’S INTERIOR Crust EARTH’S INTERIOR Mantle – layer of solid, hot rock Made of oxygen, silicon, iron, and magnesium. 2,900 km thick 68% of Earth’s mass and 82% of Earth’s volume EARTH’S INTERIOR Traveling farther into the mantle there is increasing temperatures and pressures. EARTH’S INTERIOR Crust Mantle EARTH’S INTERIOR The core makes up about 33% of the Earth’s mass but only 15% of the Earth’s volume. The core is VERY dense. Made of iron and nickel Temperatures range from 3630ºF – 5430ºF (2,000ºC – 3,000ºC) EARTH’S INTERIOR Crust Mantle Core EARTH’S INTERIOR The Earth is made up of five main physical layers. lithosphere asthenosphere mesosphere outer core inner core EARTH’S INTERIOR The crust and the upper part of the mantle are very similar, very hard and rocky. Lithosphere – the crust and the uppermost part of the mantle EARTH’S INTERIOR Lithosphere (rigid) Crust Mantle Core EARTH’S INTERIOR Material in the mantel is softer and can bend, somewhat like plastic. EARTH’S INTERIOR Asthenosphere – the soft rock layer of the Earth that can flow slowly The lithosphere floats on top of the asthenosphere. Enormous heat and pressure allow this soft, solid rock to move. EARTH’S INTERIOR Lithosphere (rigid) Asthenosphere (plastic) Crust Mantle Core EARTH’S INTERIOR Mesosphere– the hard rock layer that makes up most of the mantle Extreme pressure at this depth makes the rock very hard and unable to move like the asthenosphere. EARTH’S INTERIOR Lithosphere (rigid) Asthenosphere (plastic) Crust Mantle Mesosphere (rigid) Core EARTH’S INTERIOR The core has two parts, an outer core and inner core. Outer core – a layer of molten, liquid metal that surrounds the inner core Inner core – a dense ball of solid metal EARTH’S INTERIOR Lithosphere (rigid) Asthenosphere (plastic) Crust Mantle Mesosphere (rigid) Outer Core (liquid) Inner Core (solid) Core EARTH’S INTERIOR Diagram From: geophysics.ou.edu EARTH’S INTERIOR Diagram From: faculty.weber.edu EARTH’S INTERIOR Diagram From: spring.net EARTH’S INTERIOR Layers of the Earth Depiction EARTH’S INTERIOR Currents in the liquid outer core force the solid inner core to spin at a slightly faster rate than the rest of the planet. The currents created by the outer core create the Earth’s magnetic field. EARTH’S INTERIOR The Earth acts like a giant bar magnet. A compass will point to the Earth’s magnetic North pole. EARTH’S INTERIOR Diagram From: glossary.oilfield.slb.com EARTH’S INTERIOR Diagram From: cnx.org