Analog Seismograph

Brief Description

Portable Analog Seismograph has been designed and developed to monitor process and record the field seismic data from remote sites. The electrical signal produced by the short period seismometer (seismic sensor) in response to ground motion is fed directly to the portable analog recorder. The recorder processes the seismic signal, which is extremely low in amplitude and is highly corrupted with dominant background noise. The whole seismic data is tagged with the internally generated time clock, which can be synchronized with reference ATA Timing Signal transmitted by NPL, New Delhi. The duly processed data tagged with timing information, is finally recorded on a smoked paper wrapped on a drum.

Salient Features

The analog recorder has been matched with seismometers of different manufacturing concerns viz- model S-13/ S-500 of M/s Teledyne Geo Tech USA, model SM-3 M/s Special Design Bureau, Russia and model MK III of M/s Sensonic USA.

• It is battery powered, portable and is fully field worthy. It has less running cost and is simple in operation.
  
• It produces seismograms without any separate data retrieval unit. The seismogram is easily decipherable at a quick glance.
  
• It can record the events of several hours duration without running short of storage media.
  
• Because of the facilities for programmable drum speeds and trace separations, the seismologist can record field data on a single smoked paper for a period varying from 3.5 hours to 115 hours.
  
• Different sets of time marks (hour, minute and second) are switch selectable at the front panel.
  
• Ten switch selectable gains at a step of 6 db are provided for selection of sensitivity. Four low-pass and three high pass filter positions is switch selectable for selecting a specific signal of interest.
  

Applications

a. Monitoring of major and micro Earthquakes.
b. Study of Preshocks and After shocks.
c. Seismic noise Survey & Microzonation
d. Site selection survey for vital structures.
e. Strong Motion Recording & Studies.
f. Studies on Induced Seismicity.

Benefits

The instruments are produced totally with a view to utilize indigenous technology and to cut short the supply period, which is quite large for imported instruments. The developed technology will use to study the seismicity of a particular region. The system can also be used to detect nuclear activity by the neighboring countries.

Contact:

Central Scientific Instruments Organisation,
Chandigarh
Website: http://www.csio.res.in/