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Quality Control at ODC - IRIS

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					                                                      ORFEUS Data Center
                                                        Quality Control
                                                               Reinoud Sleeman
                                                                 Torild van Eck
                                                            Gert-Jan van den Hazel
                                                              Alessandro Spinuso
                                                                   Luca Trani
                                                                Anton van Geyt
                                                                        &
                                           Virtual European Broadband Seismic Network Consortium

                                                                sleeman@knmi.nl
                                                                www.orfeus-eu.org


                                Organizations and Research Facilities for European Seismology




ORFEUS Quality Control – Reinoud Sleeman        Managing Waveform Data and Related Metadata for Seismic Networks   Foz do Iguacu, Brazil, 13-19 Aug 2010
                                                                                                VEBSN - Virtual European
                                                                                                Broadband Seismograph Network
                                                                                                • status May 2010
                                                                                                • 500 BB stations
                                                                                                • 55 networks




ORFEUS Quality Control – Reinoud Sleeman   Managing Waveform Data and Related Metadata for Seismic Networks   Foz do Iguacu, Brazil, 13-19 Aug 2010
             Quality Control at ODC of real-time VEBSN stations

               Collecting, validating and verification of metadata (new stations)
                  station code            (NEIC/ISC registered:                      www.isc.ac.uk)
                  network code (FDSN registered: www.fdsn.org)
                  system information (sensor, digitizer, sampling rate, etc.)
                  system response (validation of completeness & consistency)




ORFEUS Quality Control – Reinoud Sleeman   Managing Waveform Data and Related Metadata for Seismic Networks   Foz do Iguacu, Brazil, 13-19 Aug 2010
             Quality Control at ODC of real-time VEBSN stations

               Collecting, validating and verification of metadata (new stations)
                  station code            (NEIC/ISC registered:                      www.isc.ac.uk)
                  network code (FDSN registered: www.fdsn.org)
                  system information (sensor, digitizer, sampling rate, etc.)
                  system response (validation of completeness & consistency)


               Initial monitoring of communication and waveform quality
                  quarantine system ( reliability, stability, gaps, ……)
                  waveform data




ORFEUS Quality Control – Reinoud Sleeman   Managing Waveform Data and Related Metadata for Seismic Networks   Foz do Iguacu, Brazil, 13-19 Aug 2010
             Quality Control at ODC of real-time VEBSN stations

                Quality Control Monitor (QCM)
                  automatic procedures for real-time data and meta-data
                                 - locations, magnitudes (Antelope ® )
                                 - station histograms (time residuals, magnitude)
                                 - Power Spectral Density (PSD) vs. Time
                                 - PQLX


                  data completeness


                  visual check of pre-packed event data (SAC, PQL, PQLX)


                  polarization analysis (manually)


                  SeisComP 3 QC parameters (DB: gaps, RMS, spikes, clock quality …..)


ORFEUS Quality Control – Reinoud Sleeman   Managing Waveform Data and Related Metadata for Seismic Networks   Foz do Iguacu, Brazil, 13-19 Aug 2010
             Quality Control at ODC – histograms per station

                                                                     •     Mb (station) – Mb (VEBSN)
      Antelope processing output                                    •     MS (station) – MS (VEBSN)
                                                                     •     Time residuals ( P-phase)




                                                                      X                                                
ORFEUS Quality Control – Reinoud Sleeman   Managing Waveform Data and Related Metadata for Seismic Networks   Foz do Iguacu, Brazil, 13-19 Aug 2010
             Quality Control at ODC – PSD vs. Time

                      overall quality of data versus time (PSD vs. time)
                                to monitor changes in behavior of seismic system
                                malfunctioning of seismic instrumentation
                                verifying and monitoring changes in meta data
                                changes in local site conditions
                                long term behavior




                                                                                       PSD at selected frequencies
        dB




                                           Julian day
ORFEUS Quality Control – Reinoud Sleeman   Managing Waveform Data and Related Metadata for Seismic Networks   Foz do Iguacu, Brazil, 13-19 Aug 2010
             Quality Control at ODC – PQLX                                                  (McNamara, Boaz)


                      stacked PSD per frequency (statistical representation)




                    high noise model
    dB




                      low noise model



                           Period (sec)                                                       Period (sec)




ORFEUS Quality Control – Reinoud Sleeman   Managing Waveform Data and Related Metadata for Seismic Networks   Foz do Iguacu, Brazil, 13-19 Aug 2010
             Quality Control at ODC – PQLX

                      tool to select stations for specific scientific studies




                                                                                              “Earth’s Hum”




                                                                    NL_HGN_BHZ




                                                                                           Courtesy Rudy Widmer

                                                                   NL_WTSB_BHZ




ORFEUS Quality Control – Reinoud Sleeman   Managing Waveform Data and Related Metadata for Seismic Networks   Foz do Iguacu, Brazil, 13-19 Aug 2010
             Quality Control at ODC – PSD vs. Time procedure


                     data extraction (30 min. segments)
                        •    less than 28 minutes is represented as a gap




ORFEUS Quality Control – Reinoud Sleeman   Managing Waveform Data and Related Metadata for Seismic Networks   Foz do Iguacu, Brazil, 13-19 Aug 2010
             Quality Control at ODC – PSD vs. Time procedure


                     data extraction (30 min. segments)
                        •    less than 28 minutes is represented as a gap

                     PSD estimation (periodogram averaging, Welch (1967)

                       •     50 % overlapping time sections (8192 samples at 40 sps)
                       •     tapering (Hanning window)
                       •     autocorrelation
                                                                                                                1
                       •     Fourier transform                                                     PSD( f ) 
                                                                                                                         2
                                                                                                                   X(f )
                                                                                                                nf
                       •     PSD averaging over the number of time sections
                       •     one-sided PSD (USGS noise models)
                                                                                                        2                   2 2
                       •     instrument response deconvolution                              Counts /Hz  (m/s ) / Hz
                                  (no digital filters, only poles, zeros and sensititvity)
                       •     PSD smoothing over 1/10-th of a decade



ORFEUS Quality Control – Reinoud Sleeman   Managing Waveform Data and Related Metadata for Seismic Networks   Foz do Iguacu, Brazil, 13-19 Aug 2010
                  Software calibration / testing

                  Synthetic input:
                   white noise
                   RMS = 1 x gain STS-1 sensor x gain Q330 digitizer
                   t = 0.025 sec


                  PSD estimation: deconvolve for STS-1 response and Q330
                                                   I(w) = O(w) / H(w)


                  Expected result:
                   RMS = 1                [360 sec. – 10 Hz]
                   PSD = 10  log ( 2 x 2 x t) = -13 dB (one-sided)
                   -10 dB @ corner frequencies (360 sec and 10 Hz )


ORFEUS Quality Control – Reinoud Sleeman   Managing Waveform Data and Related Metadata for Seismic Networks   Foz do Iguacu, Brazil, 13-19 Aug 2010
                      Synthetic test: result

                       PSD = 10  log ( 2 x 2 x t) (one-sided PSD)
                                      = -13 dB




ORFEUS Quality Control – Reinoud Sleeman   Managing Waveform Data and Related Metadata for Seismic Networks   Foz do Iguacu, Brazil, 13-19 Aug 2010
                                                            PSD at selected frequencies vs. time
                                                            ( 0.01, 0.05, 0.5, 2.0 Hz)




                                                           Noise energy in two frequency bands
                                                           vs. time
                                                           ( 0.05 – 0.1 Hz and 0.1 – 1.0 Hz )




                                                            Minimum noise level vs. frequency


ORFEUS Quality Control – Reinoud Sleeman   Managing Waveform Data and Related Metadata for Seismic Networks   Foz do Iguacu, Brazil, 13-19 Aug 2010
           Example 1




ORFEUS Quality Control – Reinoud Sleeman   Managing Waveform Data and Related Metadata for Seismic Networks   Foz do Iguacu, Brazil, 13-19 Aug 2010
           Example 1




                                                                                                  disconnected sensor ?
                                                                                                  seems not likely




ORFEUS Quality Control – Reinoud Sleeman   Managing Waveform Data and Related Metadata for Seismic Networks   Foz do Iguacu, Brazil, 13-19 Aug 2010
      Example 2




ORFEUS Quality Control – Reinoud Sleeman   Managing Waveform Data and Related Metadata for Seismic Networks   Foz do Iguacu, Brazil, 13-19 Aug 2010
      Example 2




                                                                                                  New sensor + digitizer




ORFEUS Quality Control – Reinoud Sleeman   Managing Waveform Data and Related Metadata for Seismic Networks   Foz do Iguacu, Brazil, 13-19 Aug 2010
                                                                                                  Example 4




ORFEUS Quality Control – Reinoud Sleeman   Managing Waveform Data and Related Metadata for Seismic Networks   Foz do Iguacu, Brazil, 13-19 Aug 2010
                                                                                                  Example 4




                      New temperature isolation sensor




ORFEUS Quality Control – Reinoud Sleeman   Managing Waveform Data and Related Metadata for Seismic Networks   Foz do Iguacu, Brazil, 13-19 Aug 2010
                                                                                                  Example 4




                                                                                                     ?




ORFEUS Quality Control – Reinoud Sleeman   Managing Waveform Data and Related Metadata for Seismic Networks   Foz do Iguacu, Brazil, 13-19 Aug 2010
                                                                                                  Example 4




                                                                                                     ?




ORFEUS Quality Control – Reinoud Sleeman   Managing Waveform Data and Related Metadata for Seismic Networks   Foz do Iguacu, Brazil, 13-19 Aug 2010
                                                                                                  Example 5




                                                                        suspicious gain in meta-data




ORFEUS Quality Control – Reinoud Sleeman   Managing Waveform Data and Related Metadata for Seismic Networks   Foz do Iguacu, Brazil, 13-19 Aug 2010
           ODC-VEBSN event, SOLOMON ISLANDS REGION
           On 2007/04/04 at 00:39:34.79 UTC

           Magnitude             = mb 6.2
           Latitude              = 14.43S
           Longitude             = 158.30E
           Depth                 = 30.0

                                                                                                            mb difference
           ARRIVALS:

           Net Sta                    Dist    EvAz Phase               Time            TRes Def SNR mb                    Ms          ML
           :
           GR WET                    135.24 328.2       P       00:58:50.700           -0.2    T      28.2      6.3       -       -
           OE MOA                    135.30 325.9       P       00:58:51.187            0.1    T      10.5      5.8       -       -
           OE OBKA                   135.91 324.2       P       00:58:51.833           -0.4    T       7.3      5.6       -       -
           SL LJU                    136.19 323.7       P       00:58:52.910            0.2    T      20.2      9.1       -       -
           OE KBA                    136.25 325.6       P       00:58:52.417           -0.4    T      16.2      5.8       -       -
           SL CEY                    136.42 323.4       P       00:58:52.996           -0.1    T      28.4      9.2       -       -
           OE WTTA                   137.06 326.8       P       00:58:54.122           -0.2    T      20.6      6.4       -       -
           GE STU                    137.32 330.1       P       00:58:55.376            0.6    T      12.8      6.4       -       -
           NL HGN                    137.37 334.3       P       00:58:55.045            0.2    T       8.0      6.0       -       -
           GE WLF                    138.09 333.1       P       00:58:56.009           -0.2    T       9.5      6.2       -       -
           :


ORFEUS Quality Control – Reinoud Sleeman     Managing Waveform Data and Related Metadata for Seismic Networks     Foz do Iguacu, Brazil, 13-19 Aug 2010
                                                                    6                                    9
                                                               10                                    10

          1



                                                       fNormalization




ORFEUS Quality Control – Reinoud Sleeman   Managing Waveform Data and Related Metadata for Seismic Networks   Foz do Iguacu, Brazil, 13-19 Aug 2010
        impulse response                                                   amplitude response




                                                          before update




                                                          after update




ORFEUS Quality Control – Reinoud Sleeman   Managing Waveform Data and Related Metadata for Seismic Networks   Foz do Iguacu, Brazil, 13-19 Aug 2010
    Z
                                                                                 Polarization verification




    N                                                                       E




ORFEUS Quality Control – Reinoud Sleeman   Managing Waveform Data and Related Metadata for Seismic Networks   Foz do Iguacu, Brazil, 13-19 Aug 2010
                                                                     SeisComp3 – RT QC




                                                                                                          QC parameter status
        station map / status




                                                                                                                    trace viewer



    origin information / review
ORFEUS Quality Control – Reinoud Sleeman   Managing Waveform Data and Related Metadata for Seismic Networks   Foz do Iguacu, Brazil, 13-19 Aug 2010
                           SC3 Real-Time Quality Control View




ORFEUS Quality Control – Reinoud Sleeman   Managing Waveform Data and Related Metadata for Seismic Networks   Foz do Iguacu, Brazil, 13-19 Aug 2010
                                     >= 90 % data : 53 % channels
                                     >= 95 % data : 36 % channels
                                     >= 99 % data : 10 % channels




ORFEUS Quality Control – Reinoud Sleeman   Managing Waveform Data and Related Metadata for Seismic Networks   Foz do Iguacu, Brazil, 13-19 Aug 2010
                                                                         average: 98.3 %




                                                      12 hours ODC outage per year = 0.14 %




ORFEUS Quality Control – Reinoud Sleeman   Managing Waveform Data and Related Metadata for Seismic Networks   Foz do Iguacu, Brazil, 13-19 Aug 2010
                 ORFEUS does not operate stations


                 VEBSN is a complex, heterogeneous and dynamic system


                 ODC operational for 99.86 %


                 Data gaps in order of days


                 Missing data mainly due to station problems and/or
                 communication problem ?


                 Secondary data retrieval mechanisms


ORFEUS Quality Control – Reinoud Sleeman   Managing Waveform Data and Related Metadata for Seismic Networks   Foz do Iguacu, Brazil, 13-19 Aug 2010

				
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