The Earth’s Structure A Journey to the Center of the Earth.

Presentation on theme: "The Earth’s Structure A Journey to the Center of the Earth."— Presentation transcript:

1 The Earth’s Structure A Journey to the Center of the Earth

2 The Interior of the Earth

3 The Earth’s Layers Earth can be divided into three main layers – the crust, mantle and core. The layering is due to differences in density Temperature and pressure in Earth’s interior increase with depth

4 The Crust Rocky outer layer of Earth Made up of Silicates Two types of Crust Continental Crust – rocks that make up continents; thickness between 8 -75 km Oceanic Crust – rock that makes up ocean floor; average thickness 7 km

5 The Mantle A thick layer of hot semi-solid dense rock Approximately 2850 km thick Composed of mostly iron, magnesium and aluminum. Makes up about 84% of Earth’s volume

6 “Sub Layers” w/n Crust & Mantle Lithosphere – composed of the oceanic and continental crust and the rigid upper mantle; thin outer shell of Earth; broken up into “plates”. Asthenosphere – softer and weaker rock in the mid- mantle; can flow slowly when under pressure Mesosphere – stronger lower part of the mantle

7 The Core A large sphere of metal that occupies Earth’s center Composed mostly of iron and nickel Divided into 2 parts: Outer core – composed of liquid metal; 2260 km thick Inner core – solid due to very high pressure; 1220 km thick

8 How do Scientists study Interior of Earth? Use of Seismic Waves 2 Types of Seismic Waves: S & P waves P waves: Travel through solids, liquids and gases Faster than S waves S waves Travel only through solids Speed and direction of both waves are affected by the composition of material they are traveling through

9 Shadow Zones Locations on Earth’s surfaces where neither S or P waves are detected S waves will not travel through liquid core P waves speed and direction change causing them to bend