06 Earthquakes

06 Earthquakes - such a way that the ground surface ripples or undulates most earthquake damages are caused by surface waves Rayleigh waves Cause

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(F) Earthquakes Terminology Focus The point at which the first movement or break occurs during an earthquake Epicentre The point on the earth’s surface directly above the focus Most of the major earthquake epicentres are concentrated in linear belts corresponding to plate boundaries where plate movements may build up very large stresses When an earthquake occurs, the stored up energy is released in the form of seismic waves that travel away from the focus Seismic waves Body waves: travels through the interior of the earth P waves: Compressional (longitudinal) waves; causes alternate compression and expansion of matters S waves: Shear (transverse) waves Surface waves: travels along the surface; cause rocks and soil to be displaced in
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Unformatted text preview: such a way that the ground surface ripples or undulates; most earthquake damages are caused by surface waves Rayleigh waves: Cause vertical ground motions Love waves: Cause horizontal ground motions • Sizes of earthquakes Magnitude To describe the amount of shaking/vertical motion as measured by a seismograph Richter Magnitude Scale Intensity Intensity is a (subjective) measure of the earthquake’s effects on humans and on surface features Mercalli Scale of Earthquake Intensity The surface effects produced by an earthquake depends on: Local geologic conditions Quality of construction Distance from the epicentre...
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This note was uploaded on 09/26/2011 for the course CIVIL CIVL taught by Professor Wong during the Spring '11 term at HKU.

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