Seismic Network Operations


Hockley, Texas

IU HKT commences operations on: 1995,192

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Host: University of Texas Austin
Latitude: 29.962
Longitude: -95.838
Elevation: -413
Datalogger: Q680
Broadband: STS-1VBB_w/E300
Accelerometer: FBA_ES-T_EpiSensor_Accelerometer
Telemetry Status at the NEIC: Last Data In Less Than 10 Minutes
Station Photo Station Photo Station Photo 

Vault Condition: The vault is 472 meters below surface in a salt mine. Temperature of the vault remains at approximately 37 degrees C. The pier is not isolated.

Site Geology: Located in the Willis Formation that is made of clay, silt, sand, and minor siliceous gravel. Deposited in the lower Pleistocene and is approximately 200 feet thick.

Location CodeChannel CodeInstrumentFlagsSample RateDipAzimuthDepth
30LDOCI/PAS pressure sensorCW1.000.000.00450.00
20LNZFBA ES-T EpiSensor AccelerometerCG1.00-90.000.00450.00
20LN2FBA ES-T EpiSensor AccelerometerCG1.000.0090.00450.00
20LN1FBA ES-T EpiSensor AccelerometerCG1.000.000.00450.00
20HNZFBA ES-T EpiSensor AccelerometerTG100.00-90.000.00450.00
20HN2FBA ES-T EpiSensor AccelerometerTG100.000.0090.00450.00
20HN1FBA ES-T EpiSensor AccelerometerTG100.000.000.00450.00
00VMZSTS-1VBB w/E300CH0.100.000.00450.00
00VM2STS-1VBB w/E300CH0.100.000.00450.00
00VM1STS-1VBB w/E300CH0.100.000.00450.00
00VHZSTS-1VBB w/E300CG0.10-90.000.00450.00
00VH2STS-1VBB w/E300CG0.100.0089.00450.00
00VH1STS-1VBB w/E300CG0.100.00358.00450.00
00LHZSTS-1VBB w/E300CG1.00-90.000.00450.00
00LH2STS-1VBB w/E300CG1.000.0089.00450.00
00LH1STS-1VBB w/E300CG1.000.00358.00450.00
00BHZSTS-1VBB w/E300CG20.00-90.000.00450.00
00BH2STS-1VBB w/E300CG20.000.0089.00450.00
00BH1STS-1VBB w/E300CG20.000.00358.00450.00
10VHZSTS-2 Standard-gainCG0.10-90.000.00450.00
10VH2STS-2 Standard-gainCG0.100.0090.00450.00
10VH1STS-2 Standard-gainCG0.100.000.00450.00
10LHZSTS-2 Standard-gainCG1.00-90.000.00450.00
10LH2STS-2 Standard-gainCG1.000.0090.00450.00
10LH1STS-2 Standard-gainCG1.000.000.00450.00
10HHZSTS-2 Standard-gainTG100.00-90.000.00450.00
10HH2STS-2 Standard-gainTG100.000.0090.00450.00
10HH1STS-2 Standard-gainTG100.000.000.00450.00
10BHZSTS-2 Standard-gainCG40.00-90.000.00450.00
10BH2STS-2 Standard-gainCG40.000.0090.00450.00
10BH1STS-2 Standard-gainCG40.000.000.00450.00
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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.

LocChanCal DateEpoch-SpanGradeAmp Nominal Error (dB)Amp Best Fit Error (dB)Phase Nominal Error (degree)Phase Best Fit Error (degree)SensorCal Type
10BHZ2011:274 2011:270 to No Ending TA0.0150810.0147930.124410.079551 STS-2-SGRandom
00BHZ2011:276 2011:270 to No Ending TA0.0199330.00906730.123170.1444 STS1VBBE3Random
00BH22011:276 2011:270 to No Ending TA0.0195140.00873080.124660.15754 STS1VBBE3Random
00BH12011:276 2011:270 to No Ending TA0.0201260.0090930.12270.1718 STS1VBBE3Random
  1. Current Issues.
    LN1 channel has been showing high noise levels. The STS-2.5 has been showing some spiking.
  2. 2011-10-03
    Upgraded to Q330 digitizer.