Introduction
2 Introduction
The Güralp 3TB is a three-axis seismometer
consisting of three sensors stacked vertically in a
sealed borehole sonde, designed for use in cased
boreholes with diameters between 99 mm (≈3.9 “)
and 203 mm (≈8 “).
The seismometer system is self-contained except
for its 12 – 30 V power supply, which is provided
through the same cable as the analogue data.
Sensor functions such as levelling and mass
locking are carried out through a surface control
box.
The 3TB's sensors are sensitive to ground
vibrations across thee entire seismic spectrum,
with a flat response to velocity in the frequency
range 0.0027 Hz (360 seconds) to 50 Hz. It outputs
analogue voltages representing ground velocity on
balanced differential lines. Each seismometer is
delivered with a detailed calibration sheet
showing its serial number, measured frequency
response in both long and short period sections of
the seismic spectrum, sensor DC calibration levels,
and the transfer function in poles/zeros notation.
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Issue G - November 2019
