Seismic Network Operations

IU ADK

Adak, Aleutian Islands, Alaska

IU ADK commences operations on: 1993,264

Country Flag
Host: Aleut Enterprises
Latitude: 51.882
Longitude: -176.684
Elevation: 130
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: Vault is a small concrete building built into the side of a small rise. The sides and back are covered with earth to height of the roof. Piers are concrete and are separated from the floor and attached to rock.

Site Geology: The Aleutian Islands are of volcanic origin. Bedrock at vault is fractured basalt.

Location CodeChannel CodeInstrumentFlagsSample RateDipAzimuthDepth
20LNZFBA ES-T EpiSensor AccelerometerCG1.00-90.000.000.00
20LN2FBA ES-T EpiSensor AccelerometerCG1.000.0090.000.00
20LN1FBA ES-T EpiSensor AccelerometerCG1.000.000.000.00
10VHZTrillium 240 broad bandCG0.10-90.000.000.00
10VH2Trillium 240 broad bandCG0.100.0090.000.00
10VH1Trillium 240 broad bandCG0.100.000.000.00
10LHZTrillium 240 broad bandCG1.00-90.000.000.00
10LH2Trillium 240 broad bandCG1.000.0090.000.00
10LH1Trillium 240 broad bandCG1.000.000.000.00
10BHZTrillium 240 broad bandCG40.00-90.000.000.00
10BH2Trillium 240 broad bandCG40.000.0090.000.00
10BH1Trillium 240 broad bandCG40.000.000.000.00
00VHZSTS-1VBB w/E300CG0.10-90.000.000.00
00VH2STS-1VBB w/E300CG0.100.0090.000.00
00VH1STS-1VBB w/E300CG0.100.000.000.00
00LHZSTS-1VBB w/E300CG1.00-90.000.000.00
00LH2STS-1VBB w/E300CG1.000.0090.000.00
00LH1STS-1VBB w/E300CG1.000.000.000.00
00BHZSTS-1VBB w/E300CG20.00-90.000.000.00
00BH2STS-1VBB w/E300CG20.000.0090.000.00
00BH1STS-1VBB w/E300CG20.000.000.000.00
20HNZFBA ES-T EpiSensor AccelerometerTG100.00-90.000.000.00
20HN2FBA ES-T EpiSensor AccelerometerTG100.000.0090.000.00
20HN1FBA ES-T EpiSensor AccelerometerTG100.000.000.000.00
10HHZTrillium 240 broad bandTG100.00-90.000.000.00
10HH2Trillium 240 broad bandTG100.000.0090.000.00
10HH1Trillium 240 broad bandTG100.000.000.000.00
PDF, All
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Heliplot
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Latency
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Availability, Since 1972
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Availability, 2 Month
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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
10BHZ2013:0152011:264 to No Ending TimeA0.0111780.00770.142010.087994TR240Random
00BHZ2013:0142009:200 to No Ending TimeA0.0183770.0105820.128350.19871STS1VBBE3Random
00BH12013:0142009:200 to No Ending TimeA0.017510.0107360.126130.20276STS1VBBE3Random
00BH22013:0142009:200 to No Ending TimeA0.0188810.00887150.140230.19495STS1VBBE3Random
  1. 2012-08-07
    Power and last mile communication link restored fixing an eight month outage.
  2. 2011-09-24
    Power systems upgrade completed.
  3. 2009-07-27
    Upgraded to Q330 digitizer.