Seismogram


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seismogram

[′sīz·mə‚gram]
(engineering)
The record made by a seismograph.

Seismogram

 

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.

I. V. GORBUNOVA

References in periodicals archive ?
(2005) to locate records of the Benavente earthquake allowed to recover 31 potentially useful seismograms of this event (Table 1).
Filtering of seismogram. It was applied a bandpassfilter process for each seismogram over the frequency bands 20-40 Hz, in order to detect heterogeneities whose wavelength allowed the tunnel identification.
The measurements or parameters consist of ratios of the "high energies" contained within predetermined "velocity windows" on the seismograms [18].
danger Firemen check out a roof after part of its chimney crashed into the street during Saturdays earthquake in Folkestone QUAKE LINES Seismologists David Booth, left, and Glen Ford from the British Geological Survey in Edinburgh look at a seismogram of the earthquake which hit Kent
Below, a seismogram chart of Tiksi, Russia, recorded during the claimed test.
In addition to this field work Ralph develops synthetic seismogram methods for predicting sound propagation in the seafloor.
Acting as a table of contents for the larger IRIS seismogram archives, the Data Management System workstation in Austin displays a list summarizing all the seismograms in the archive that have data for the earthquake in question.
In each seismogram, there were 50 traces corresponding to 50 offsets, including zero.
The 1D forward modeling or synthetic seismogram is used to correlate well data and surface seismic data.