Seismic Network Operations

IU MAJO

Matsushiro, Japan

IU MAJO commences operations on: 1990,230

Country Flag
Host: Japan Meteorological Agency
Latitude: 36.546
Longitude: 138.204
Elevation: 405
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 located in an underground tunnel complex sealed with concrete walls. Floors are concrete with piers isolated from the floor and attached to bedrock. Temperature and humidity are stable.

Site Geology: Rock is tertiary sedimentary intruded by quartz diorite.

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
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
10VHZSTS-2 High-gainCG0.10-90.000.000.00
10VH2STS-2 High-gainCG0.100.0087.000.00
10VH1STS-2 High-gainCG0.100.00357.000.00
10LHZSTS-2 High-gainCG1.00-90.000.000.00
10LH1STS-2 High-gainCG1.000.00357.000.00
10HHZSTS-2 High-gainTG100.00-90.000.000.00
10HH2STS-2 High-gainTG100.000.0087.000.00
10LH2STS-2 High-gainCG1.000.0087.000.00
10BHZSTS-2 High-gainCG40.00-90.000.000.00
10HH1STS-2 High-gainTG100.000.00357.000.00
10BH2STS-2 High-gainCG40.000.0087.000.00
10BH1STS-2 High-gainCG40.000.00357.000.00
00VHZSTS-1VBB w/E300CG0.10-90.000.000.00
00VH2STS-1VBB w/E300CG0.100.0087.000.00
00VH1STS-1VBB w/E300CG0.100.00357.000.00
00LHZSTS-1VBB w/E300CG1.00-90.000.000.00
00LH2STS-1VBB w/E300CG1.000.0087.000.00
00LH1STS-1VBB w/E300CG1.000.00357.000.00
00BHZSTS-1VBB w/E300CG20.00-90.000.000.00
00BH2STS-1VBB w/E300CG20.000.0087.000.00
00BH1STS-1VBB w/E300CG20.000.00357.000.00
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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
10BHZ2012:199 2011:022 to No Ending TiA0.0153890.0144290.120860.11492 STS-2-HGRandom
00BHZ2011:021 2009:311 to No Ending TiA0.0236250.00847870.1380.17975 STS1VBBE3Random
00BH12011:021 2009:311 to No Ending TiA0.0132860.00860940.106840.15083 STS1VBBE3Random
00BH22011:021 2009:311 to No Ending TiA0.0137270.00898630.103780.14607 STS1VBBE3Random
  1. Current Issues
    The vertical component of the STS-2 has some LP pulsing.
  2. 2012-07-31
    STS-1 baseplate cables replaced fixing over damped long period response.
  3. 2009-11-07
    Upgraded to Q330 digitizer.