# Earth Quake Essay

470 Words2 Pages
uake Filename: EarthQuake.xls 1. Problem: Modeling earthquake aftershocks 2. Nature of data: 4. Column Description A Date B Hrs C Minutes D Magnitude of earth quake as reported by India meteorology department (IMD) E Magnitude of earth quake at epicentral distance ( 50 as reported by United States Geological Survey (USGS) (mb) F Magnitude of earth quake at epicentral distance ( 150 as reported by National Geophysical Research Institute (NGRI) (Ms) G Coda duration (seconds) at 1mm of background noise level H Coda duration (seconds) at 2mm of background noise level I Coda duration (seconds) at 6mm of background noise level J Coda duration (seconds) at 10mm of background noise level 5. Background: Seismology is the study of earthquakes. An earthquake creates shock waves that travel from epicenter outwards. Like any waveform these waves have two main features. One is amplitude and the other is period. Amplitude is the maximum height from the x axis [or alternatively half of the distance between peak and trough] while period is the distance along x axis between two successive peaks. Traditionally magnitude of earthquakes is measured on Richter scale. Richter value refers to local magnitude of energy released by an earthquake. Range of Richter scale is 0-9, highest recorded so far being 8.9. These values are on a log scale. When the value goes up from 4 to 5 it means the energy released becomes 10 fold. Richter scale 5 means a ground movement of about 1 mm at a distance of 10 km from the epicenter. The magnitude is based on amplitude and period information of the seismic waves. These parameters are difficult to measure because the signal becomes faint on a visible recording device. A recent alternative method is based on