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The record made by a seismograph.



the record produced by recording seismic oscillations with a seismograph. Recording techniques differ. The most common type of record is made on photosensitive paper using a light beam reflected from a small mirror on the pendulum of the seismometer or galvanometer. A record can also be made by pen point on smoked paper, by pen and ink on ordinary paper, and by a heated needle on chemically treated paper. Equipment is now being built that will make it possible to record seismic oscillations in digital code on magnetic tape; such data can then be fed into a computer.

International designations based on Latin names have been adopted to describe seismograms. Precise time marks are entered on the seismogram parallel to the record of oscillations; the length of a 1-min line on a seismogram may vary from 10 mm to a few millimeters, depending on whether the record is of short-period oscillations (as in seismic exploration) or long-period oscillations (as from remote earthquakes). Seismograms are used to establish the arrival time of various seismic waves at the observation point; the time of an earthquake’s occurrence and the location of the focus are determined from seismic travel-time curves. The magnitudes of amplitudes and periods of oscillations are used in determining the energy of an earthquake (the magnitude) and the intensity of oscillation at the observation point. The record of the wave picture from an earthquake or explosion reveals the structure of the medium through which the seismic waves are propagated.


References in periodicals archive ?
He E-mails this request file to Austin, where a computer operator retrieves the appropriate seismograms from the IBM mainframe.
Using sonie and density logs, a synthetic seismogram was build and tied to a migrated seismic seetion along the well path.
The length of the inverted seismogram can be pre-set individually for each station; the used time windows are given in Tab.
The synthetic seismogram should also look something like the actual reflection profile.
Comparing a specific seismic event with well-log data is frequently done through the intermediary of a modeling technique called a synthetic seismogram match.
Synthetic seismogram is a direct one-dimensional model of acoustic wave moving through the earth.
Combining the electrokinetic effect and the synthetic seismogram, Ren et al.
And we listen to the music of the Earth on a seismogram to figure out what's in the planet's center.
This study explains: velocity analysis, analysis of seismic time section, generation of depth section to identify various reflectors in the region and to analyze structural picture and synthetic seismogram generation.
To be useful, the various packets of energy that can be seen on the seismogram must be identified as refractions, reflections, P-waves or S-waves, etc.