Apple QuickTime movie | 1998-04-14 | 18.3 MB | 720x480 | 29.97fps | 1 minute, 47 seconds | [MooV/TVOD]
Transcription: At a handful of seismic observatories, seismologists such as John Ebel can listen to the Earth as it quivers from jolts both natural and man-made. Logarithms are used to convert the squiggles on a seismogram into numbers on a scale that represent how much the Earth is shaking. The reason why we use logarithms rather than just use, say, a linear scale is because the range of ground motions that we deal with in seismology is so large, for instance, for a magnitude 2 earthquake, the ground motions at the source, at the earthquake source, are very, very small fractions of an inch. We're talking ab ...