relatively smaller earthquakes occurring in vicinity of main shock currently

Relatively smaller earthquakes occurring in vicinity

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-relatively smaller earthquakes occurring in vicinity of main shock- currently not useful for earthquake prediction o Aftershock - smaller shocks that follow main shock and distributed throughout fault plane o Damage - generally greatest damage near epicenter, but other factors may influence this e.g. ground type or bedrock o Seismographs -measures magnitude of vertical and horizontal motion related to earthquakes o Seismograms -records from seismographs Determining the size of an earthquake 1. A geologist measures the amplitude of the largest seismic wave (23mm 2. the time interval between the P-wave and S-wave arrivals (24 s) to determine the distance from the epicenter to the station (210 km) 3. By plotting the two measurements on these graphs and connecting the point, the geologist determines the Richter magnitude of the earthquake (5.0)
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Richter scale - logarithmic (i.e. each unit represents 10x more ground motion than the previous one) or a factor of 33x more energy). Another measure of damage-shaking intensity determined by the modified Mercalli Scale Moment Magnitude (Mw)-determines strain energy released from entire fault surface (total energy released) o Most recent method Patterns of faulting Earthquakes develop as result of slippage along fault plane
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  • Spring '07
  • BAKSI
  • Geology, Seismic Waves

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