Seismic Network Operations


San Juan, Puerto Rico

IU SJG commences operations on: 1993,146

Country Flag
Host: US Geological Survey
Latitude: 18.109
Longitude: -66.15
Elevation: 420
Datalogger: Q330
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 seismometer vault is built into a hillside and has an overburden of approximately 3 meters. Piers are isolated from floor and connected to bedrock. Temperature and humidity in the vault are stable. There is a four lane highway located 1100 feet from the vault. Traffic is heavy, and includes large trucks.

Site Geology: The vault is on interfingering lenticular units of volcanic breccia, conglomerate, sandstone and siltstone of cretaceous age. Seismometer piers are attached to decomposed rock of these materials.

Location CodeChannel CodeInstrumentFlagsSample RateDipAzimuthDepth
30BDOCI/PAS pressure sensorCW40.
10BH1STS-2 High-gainCG40.
00BH1STS-1VBB w/E300CG20.
10BH2STS-2 High-gainCG40.000.0090.000.00
00BH2STS-1VBB w/E300CG20.000.0090.000.00
10BHZSTS-2 High-gainCG40.00-
00BHZSTS-1VBB w/E300CG20.00-
10HH1STS-2 High-gainTG100.
10HH2STS-2 High-gainTG100.000.0090.000.00
10HHZSTS-2 High-gainTG100.00-
20HN1FBA ES-T EpiSensor AccelerometerTG100.
20HN2FBA ES-T EpiSensor AccelerometerTG100.000.0090.000.00
20HNZFBA ES-T EpiSensor AccelerometerTG100.00-
30LDOCI/PAS pressure sensorCW1.
10LH1STS-2 High-gainCG1.
00LH1STS-1VBB w/E300CG1.
10LH2STS-2 High-gainCG1.000.0090.000.00
00LH2STS-1VBB w/E300CG1.000.0090.000.00
10LHZSTS-2 High-gainCG1.00-
00LHZSTS-1VBB w/E300CG1.00-
20LN1FBA ES-T EpiSensor AccelerometerCG1.
20LN2FBA ES-T EpiSensor AccelerometerCG1.000.0090.000.00
20LNZFBA ES-T EpiSensor AccelerometerCG1.00-
10VH1STS-2 High-gainCG0.
00VH1STS-1VBB w/E300CG0.
10VH2STS-2 High-gainCG0.100.0090.000.00
00VH2STS-1VBB w/E300CG0.100.0090.000.00
10VHZSTS-2 High-gainCG0.10-
00VHZSTS-1VBB w/E300CG0.10-
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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
10BHZ2012:138 2010:362 to No Ending TiA0.015060.0142330.128210.11531 STS-2-HGRandom
00BHZ2012:137 2010:361 to No Ending TiA0.0164010.00871960.138550.12456 STS1VBBE3Random
00BH22012:137 2010:361 to No Ending TiA0.0234750.0140040.140890.10495 STS1VBBE3Random
00BH12012:137 2010:361 to No Ending TiA0.0167070.00891010.131270.11205 STS1VBBE3Random
  1. Current Issues
    LNZ Episensor component is noisy.
  2. 2010-04-22
    Upgraded to Q330 digitizer.