Seismic Network Operations
Raoul, Kermadec Islands
IU RAO commences operations on: 2004,200
|Host:||Institute of Geological and Nuclear Sciences|
|Telemetry Status at the NEIC:||Last Data In Less Than 10 Minutes|
Site Description: Station is located on a 100m bluff on the small volcanic island.
Vault Condition: STS-2, STS-1 vertical and FBA-23 are located in a very shallow concrete vault.
|Location Code||Channel Code||Instrument||Flags||Sample Rate||Dip||Azimuth||Depth|
|00||VK1||Quanterra DA temperature monitor||CW||0.10||0.00||0.00||0.50|
|00||VE1||Quanterra DA voltage monitor||CW||0.10||0.00||0.00||0.50|
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As part of the annual calibration process, the USGS runs a sequence that includes a random, a step, and several sine wave calibrations. The USGS analyzes the random binary calibration signal in order to estimate the instrument response. The figures below show the results from the analysis of the most recent processed calibration at the station.
We use an iterative three-step method to estimate instrument response parameters (poles, zeros, sensitivity and gain) and their associated errors using random calibration signals. First, we solve a coarse non-linear inverse problem using a least squares grid search to yield a first approximation to the solution. This approach reduces the likelihood of poorly estimated parameters (a local-minimum solution) caused by noise in the calibration records and enhances algorithm convergence. Second, we iteratively solve a non-linear parameter estimation problem to obtain the least squares best-fit Laplace pole/zero/gain model. Third, by applying the central limit theorem we estimate the errors in this pole/zero model by solving the inverse problem at each frequency in a 2/3rds-octave band centered at each best-fit pole/zero frequency. This procedure yields error estimates of the 99% confidence interval.
|Loc||Chan||Cal Date||Epoch-Span||Grade||Amp Nominal Error (dB)||Amp Best Fit Error (dB)||Phase Nominal Error (degree)||Phase Best Fit Error (degree)||Sensor||Cal Type|
|10||BHZ||2006:111||2004:235 to 2009,221||A||0.015579||0.014954||0.11533||0.12983||STS-2-HG||Random|
|00||BHZ||2006:110||2004:235 to 2009,221||B||0.86216||0.074471||2.7676||4.7495||STS1VVBB||Random|
Current IssuesSTS-1 Z channel is not functioning since August 2009. The STS-2 has been showing frequent spiking since late Feb. 2012. An upgrade trip is planned for May 2013.