struct-materials

struct-materials - Earth Structure, Materials, Systems, &...

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This page last updated on 23-Aug-2011 EENS 2040 Natural Disasters Tulane University Prof. Stephen A. Nelson Earth Structure, Materials, Systems, and Cycles Objectives Since this course is about how earth processes can adversely affect us as human beings, we need to first discuss some of the basic principles of the science of Earth - that is geology. The objectives here will be to gain an understanding of : 1. Earth's place in the Solar System and how it formed. 2. the structure of Earth and the materials from which it is made. 3. minerals and rocks, including the most important minerals and rocks for understanding natural disasters. 4. Earth processes, the energy that drives the processes, and the fundamentals of energy transfer in the Earth. 5. the time scale upon which Earth processes act. 6. plate tectonics - important in understanding earthquakes and volcanic eruptions. 7. geologic processes that cycle energy and materials through Earth systems. The Earth in the Solar System The Solar System The Earth is one of nine planets (eight if Pluto is not considered a planet) in the solar system In addition to the planets, many smaller bodies called asteroids, comets, meteoroids are present. All objects in the solar system orbit around the Sun. The four planets closest to the Sun (Mercury, Venus, Earth, and Mars) have high densities because they are mostly composed of rock, and are called the Terrestrial Planets. The five planets outside the orbit of Mars (Jupiter, Saturn, Uranus, Neptune, and Pluto) have low densities because they mostly composed of gases, and are called the Jovian Planets. 8/23/2011 Page 1 of 20
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Origin of the Solar System Original Solar Nebula Condensation of the Sun about 6 billion years ago Condensation of the Planets about 4.5 billion years ago. Process is continuing today, although at a much slower rate. The Planet Earth Interior Structure of Earth The Earth has a radius of about 6371 km, although it is about 22 km larger at equator than at poles. Density, (mass/volume), Temperature, and Pressure increase with depth in the Earth. The Earth has a layered structure. This layering can be viewed in two different ways (1) Layers of different chemical composition and (2) Layers of differing physical properties. Compositional Layering Crust - variable thickness and composition Continental 10 - 70 km thick Oceanic 8 - 10 km thick Mantle - 3488 km thick, made up of a rock called peridotite. Core - 2883 km radius, made up of Iron (Fe) with some Nickel (Ni) 8/23/2011 Page 2 of 20
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Layers of Differing Physical Properties Lithosphere - about 100 km thick (up to 200 km thick beneath continents), very brittle, easily fractures at low temperature. Asthenosphere
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This note was uploaded on 02/01/2012 for the course EENS 2040 taught by Professor Nelson during the Fall '11 term at Tulane.

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struct-materials - Earth Structure, Materials, Systems, &...

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