ERTH 2415 Lecture Notes - Lecture 5: Seismic Wave, Inverted Pendulum, Seismometer
5 Dec 2018
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Document Summary
Earthquakes are caused by sudden movements along faults: stress builds up over several years before it is released. Magnitude: amount of energy released during an earthquake. Slip: displacement between two rock blocks: larger the slip, larger the earthquake. Rupture area: surface where rocks have moved. The longer the ground shakes, the larger the rupture. Wave: oscillation in space and time travelling away from an initial disturbance. Seismic waves: waves caused by the release of energy in the earth. Amplitude is the maximum value measured from the equilibrium. Attenuation is the loss of amplitude as the wave propagates away from the source (i. e. further away from hypocentre, less bad the quake) Period t [s]: time between two successive crests or troughs, frequency f [hz]: number of waveforms in 1 second: t [s] = 1/f [hz] Wavelength l [m]: distance between two successive crests or troughs. Seismograph: an instrument that records ground motion.
