Observation system of the portable broadband seismograph consists of a seismometer, a digital recording unit and lead & solar-panel battery power supplies.
The CMG-40T portable seismometer (Guralp System LTD.) have been utilized with a three-component velocity-response (flat frequency response for velocity from 0.1 s to 20 s) of small-packaged design. The CMG-40T was operated with low-gain mode and 2 x 400 V s/m.
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The signal is digitized at the sampling frequency rate of 10-20 Hz with a dynamic range of about 90 dB (16 bits) after being passed through an anti-aliasing analog filter, and then stored on a hard-disk (2GB), or on a CF (4GB, 32GB). This process was carried out using a digital data recorders (LS8000-WD, -XT, & LS8800).
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Power supply to eight batteries (70Ah x 8) at each station was provided by five solar panels using an over-charge prevention device. The total power of the solar panels was about 250 W at 12 V DC and the total capacity of the lead batteries was 100 x 5 Ah. This system can operate continuously except in the dark and cold season in Antarctica.
