arrivals of the earthquake’s P and S waves (the S-P interval) on the seismograms from three different stations. The interval is measured to the closest second and then a graph is used to convert the S-P interval to the epicenter distance. Using information from three stations, the epicenter is triangulated.Results and conclusions –Tables –
ResultsFigure 3. Actual seismogram, but from a fictitious seismic station, and with the time scalealtered for convenience in this lab exercise. An orange line has been drawn between the beginnings of the P and S waves. Because MS Word does not allow highly accurate positioning, the orange line does not exactly line up with the red and green lines. This deficiency in MS Word will mean that results in this lab will not be exact. Macintosh computers may give more accurate results.
Figure 4. Western United States, showing the location of the fictitious seismic stations in Albuquerque,Boise, and Sacramento. For explanations of the circles see the text.Table 1. Epicenter Distances from Three Seismic Stations.
Station NameS-P time interval Δt(sec)tp(sec)Distance toepicenter (km)Radial distance on map(in)AlbuquerqueBoise79.58170.831026.69684.46Sacramento30.9666.46399.42266.28
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- Spring '14
- Seismology, Seismic wave, Epicenter, seismic stations, epicenter location