seismograph

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seismograph

an instrument that registers and records the features of earthquakes. A seismogram is the record from such an instrument

seismograph

(sÿz -mŏ-graf, -grahf) An instrument used in seismology to detect and record the passage of seismic waves, normally by making a continuous recording of the position of a suspended mass in relation to a frame fixed to the ground.

Seismograph

 

an instrument that records oscillations of the ground caused by seismic waves.

Figure 1. Diagram of a seismograph: (1) seismometer weight, (2) damper (device to attenuate the free oscillations of the weight), (3) device for converting the movement of the weight into an electrical signal, (4) filter-amplifier, (5)recorder

A seismograph (Figure 1) consists of a seismometer—an instrument that receives the seismic signal—and a recording device. The basic part of the seismometer is a weight connected with the case of the instrument by elastic couplings, for example, a pendulum. The case of the instrument is rigidly fixed to the object being studied. When the object oscillates, inertia causes the weight to move relative to the case. In most modern seismometers, this movement is converted into an electrical signal, which is recorded, usually in analogue form, by a mechanical, photographic, or magnetic recorder. Coded digital recording is sometimes used to increase the dynamic range and for convenience in subsequent computer processing.

There are also simpler seismographs, in which the movement of the seismometer weight is magnified mechanically or optically and is recorded by a mechanical or photographic recorder.

D. P. KIRNOS

seismograph

[′sīz·mə‚graf]
(engineering)
An instrument that records vibrations in the earth, especially earthquakes.
References in periodicals archive ?
The epicenter of the quake was at 34.52 degrees latitude and 45.69 degrees longitude, with a depth of eight km, the Tehran University's Seismography Center was quoted by Iran's official news agency IRNA as saying.
The tremor occurred at 10:15 local time (GMT +4:30 hours), according to a report from the seismography center affiliated with Tehran University Geophysics Institute.
According to the report of seismography center affiliated to Tehran University Geophysics Institute, the second tremor occurred at 00:41 hours local time ( 20:11 hours GMT) and its epicenter was at 35.46 degrees latitude and 54.45 degrees longitude.
According to a report by the Seismography center of Fars province affiliated to Tehran University Geophysics Institute, the tremor occurred at 03:10 hours local time (2240 GMT).
The 30-second quake was caused by a collision between the Caribbean and North American plates, said seismography expert Gonzalo Cruz from the Honduras National Autonomous University.
The tremors occurred at 14:37 local time (UTC +4:30), according to a report from the seismography center affiliated with Tehran University Geophysics Institute, Iran's state-run IRINN TV reported July 22.
The tremor occurred at 6:00 PM local time and its epicentre was at 37.8 degrees latitude and 44.59 degrees longitude, Tehran University's seismography centre said in a statement.
The tremor occurred at 07:07 local time (GMT +4:30 hours), according to a report from the seismography center affiliated with Tehran University Geophysics Institute.
The Seismography Center of the Country, affiliated to the Geophysics Institute of Tehran University reported the time of the quake at 19:50 local time, (1520 GMT).
The tremors occurred at 13:05 local time (UTC +4:30), according to a report from the seismography center affiliated with Tehran University Geophysics Institute, Iran's state-run IRINN TV reported.
According to the seismography center affiliated to Tehran University Geophysics Institute, the tremor occurred at 7:49 local time (GMT +4:30 hours), with epicenter at 51.79 degrees latitude and 28.62 degrees longitude at a depth of 10 kilometers underground.
According to the report of seismography center affiliated to Tehran University Geophysics Institute, the tremor occurred at 02:28 hours local time ( 21:58 hours GMT) and its epicenter was at 30.73 degrees latitude and 51.40 degrees longitude.