ERTH 2415 Lecture Notes - Seismic Wave, Torino Scale, Oceanic Crust
18 Aug 2014
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Document Summary
Natural disaster: extreme natural event in which a large amount of energy is released in a short time with catastrophic consequences for life and infrastructure in the vicinity. Natural hazard: source of danger that exists in the environment and that has the potential to cause harm. Frequency number of similar events per unit time. Return period: length of time between similar events. Magnitude: amount of energy fuelling a natural event. Four energy sources that fuel earth"s natural processes: earth"s internal energy, gravity, solar energy. Solar nebula: rotating disk of cosmic gas and dust. Differentation: gravity causes denser material as you approach centre of planet. Centre of earth is hot because of: residual impact from planetary accretion, and the decay of radioactive elements uranium, thorium, and potassium. Global trends: number of man-made disasters has been increasing in recent years. Introduction of health and safety policies in emerging economies: number of great natural disasters is increasing with time.
