[STT51-P07] Calibration of broadband seismographs based on the teleseismic records
Keywords:broadband seismograph, calibration, quality-control
The method is based on comparisons between teleseismic surface wave records at a target station and those at multiple surrounding reference stations, from which we estimate the corner period, damping factor and sensitivity in the instrumentation response at the target station. We applied the method to F-net broadband seismometers in Japan.
For STS-1 seismometer of vertical component at TMR station, we could not recognize obvious errors in the corner period and sensitivity. However, the damping factor had increased gradually since 2005 and reached about 2.0 in 2011. After the leveling of the seismometer in November 2011, the damping factor returned to about 0.7. For STS-2 seismometer of vertical component at SHR station, the sensitivity had been about half of the normal value from start of the observation to September 2012. After the replacement of the host-box, the sensitivity settled at normal value.
The estimated calibration values will be useful for the various research using the broadband seismometer data.