EES-1000 Lecture Notes - Lecture 10: Hypocenter, Epicenter, Volcanism
6 Nov 2016
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Document Summary
Earth shaking caused by a rapid release of energy. Due to tectonic stresses that cause rocks to break. Energy moves outward as an expanding sphere of waves. This waveform energy can be measures around the globe. Causes: elastic rebound theory: relative motion between fault blocks causes rock to deform slightly, continued stress will cause the rocks to break, releasing earthquake energy. Focus the spot within the earth where earthquake waves originate. Seismic waves: body waves pass through earth"s interior. Travel only through solids, not liquids, or gases. Slower: surface waves travel along earth"s surface. *these waves are the slowest and most destructive. *need a minimum of three stations to pinpoint the epicenter. The point of intersection of 3 stations is the epicenter. Size is described by either intensity or magnitude. Mercalli intensity scale degree of shaking damage. Roman numerals assigned to different levels of damage. 100,000 with magnitude greater than 3 per year.
