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Seismic Quality Assurance. Rick Benson IRIS DMC. Why Routine Quality Control ?. The sooner problems are detected the sooner they can be fixed Sensor malfunctions, misconfigurations, aging Digitizer & recorder malfunctions Vault problems: tilting, settling, etc Cable & connection problems

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Seismic quality assurance

Seismic Quality Assurance

Rick Benson

IRIS DMC

Data Management Workshop Foz do Iguassu- Brazil


Why routine quality control
Why Routine Quality Control ?

The sooner problems are detected the sooner they can be fixed

  • Sensor malfunctions, misconfigurations, aging

  • Digitizer & recorder malfunctions

  • Vault problems: tilting, settling, etc

  • Cable & connection problems

  • Telemetry issues

  • Timing problems

  • Many, many other potential issues

Data Management Workshop Foz do Iguassu- Brazil


Qc at the iris dmc
QC at the IRIS-DMC

The Challenge:

A small number of analysts tasked to perform QC on hundreds of stations and thousands of channels (without routine event review).

The Solution:

Minimize manual analyst work (obviously) by automating as many measurements and monitoring systems as possible and making manual analysis as efficient as possible.

Data Management Workshop Foz do Iguassu- Brazil


Manual qc at the dmc
Manual QC at the DMC

  • Visual review of raw data for selected events and, importantly, selections with no events

  • Visual review of filtered (e.g. 30-300 seconds) data where sensor problems can sometimes be detected before they are evident in the unfiltered data

  • Polarity checks using large events and the quadrant method

  • Check residuals between reviewed phase picks and predicted arrivals for gross time or location errors

  • Review of measurements and alerts from automated systems

  • Etc.

Data Management Workshop Foz do Iguassu- Brazil


Quick horizontal polarity check

N out

Z out

270º

90º

All in phase

E out

180º

Quick Horizontal Polarity Check

The “quadrant method” allows an analyst to perform a rough check of

3-component sensor horizontal polarity.

Compare the P wave first motion of a relatively large event between the

3 components to determine back azimuth:

Aleutian Island event :: Texas, USA station (BA: ~317°)

* Assumes Z component polarity is correct.

Data Management Workshop Foz do Iguassu- Brazil


Automated qc at the dmc quality analysis control kit quack
Automated QC at the DMCQuality Analysis Control Kit(QUACK)

  • Automated QC measurements for incoming real-time data at the DMC

  • Tracks a number of simple parameters (signal RMS, mean, gaps, overlaps, etc.) in addition to more complicated analyses (PSD/PDF, STA/LTA)

  • Generates daily reports, using thresholds to control what information is included in the report in order to reduce the number of issues that need attention

Data Management Workshop Foz do Iguassu- Brazil


Tracking signal rms
Tracking Signal RMS

Data Management Workshop Foz do Iguassu- Brazil


Daily rms indicates problems
Daily RMS Indicates Problems

Data Management Workshop Foz do Iguassu- Brazil


Tracking signal mean
Tracking Signal Mean

Data Management Workshop Foz do Iguassu- Brazil


Tracking data flow
Tracking Data Flow

Data Management Workshop Foz do Iguassu- Brazil


Tracking sta lta values
Tracking STA/LTA Values

Data Management Workshop Foz do Iguassu- Brazil


Pdf of power spectral density
PDF of Power Spectral Density

Data Management Workshop Foz do Iguassu- Brazil


Clickable pdfs to find time dependencies
Clickable PDFs to Find Time Dependencies

Data Management Workshop Foz do Iguassu- Brazil


Pdf calculation
PDF Calculation

  • Current implementations require Mini-SEED and SEED (RESP) system response information

  • PDF calculation available in the new PQLX analysis package

  • An older stand-alone PDF package is available: http://geohazards.cr.usgs.gov/staffweb/mcnamara/Software/PDFSA.html

  • PDFs calculated daily for real-time data received at the IRIS-DMC, stored in database

Data Management Workshop Foz do Iguassu- Brazil


Tide analysis
Tide Analysis

  • Primary gravitational tides are predictable

  • Most seismic sensors are not designed for such low frequencies & response information may not address them

  • Pretty much only a true broadband sensor will record the tides

    The idea:

    compare recorded seismic data to predicted gravitational tides

  • Tests both waveform data (polarity, shape) and metadata (instrument response)

Data Management Workshop Foz do Iguassu- Brazil


Tide comparison at iu saml
Tide Comparison at IU.SAML

Data Management Workshop Foz do Iguassu- Brazil


Tide comparison at ta h02a
Tide Comparison at TA.H02A

Data Management Workshop Foz do Iguassu- Brazil


Tide comparison at pr icm
Tide Comparison at PR.ICM

Data Management Workshop Foz do Iguassu- Brazil


Tide comparison without response information
Tide Comparison Without Response Information

Data Management Workshop Foz do Iguassu- Brazil


Tide prediction software
Tide Prediction Software

  • syntides - Synthetic Earth Gravity Tides (IRIS-DMC)

    • Output: Mini-SEED, SAC or ASCII tide synthetics

    • Convolves instrument response (SAC format)

    • Tide calculation a port of the SPOTL ‘ertid’ program

  • SPOTL - Some Programs for Ocean-Tide Loading

    • Output: ASCII text

    • Includes software to calculate solid earth gravity tide, ocean loading components, etc.

    • Written by Duncan Agnew, UCSD

Data Management Workshop Foz do Iguassu- Brazil


Seed metadata verfication
SEED Metadata Verfication

verseed - verifies base SEED data structure and formatting (IRIS-DMC)

  • Works with full SEED, dataless and Mini-SEED combined with dataless SEED (verseed -a)

  • Includes multiple levels (1-4) of diagnostic information

  • Basic metadata verification but not response evaluation

  • C program that runs on Solaris, Linux and Mac OSX

Data Management Workshop Foz do Iguassu- Brazil


Verseed example output
verseed example output

Data Management Workshop Foz do Iguassu- Brazil


Other verseed examples
Other verseed Examples

Data Management Workshop Foz do Iguassu- Brazil


Seed response evaluation
SEED Response Evaluation

evalresp - evaluates system amplitude and phase response using SEED RESP format. C program that runs on Solaris, Linux & Mac OSX.

JEvalResp - Java version of evalresp, runs anywhere Java is available. Reads either SEED RESP format or fetches response information from a DHI server.

JPlotResp - evaluates and plots system amplitude and phase response using SEED RESP format. Reads either SEED RESP format or fetches response information from a DHI server.

Data Management Workshop Foz do Iguassu- Brazil


Jplotresp usage
JPlotResp Usage

Data Management Workshop Foz do Iguassu- Brazil


Jplotresp console
JPlotResp Console

Data Management Workshop Foz do Iguassu- BrazilData Management Workshop Foz do Iguassu- Brazil


Jplotresp output
JPlotResp Output

Data Management Workshop Foz do Iguassu- Brazil


Jplotresp output per stage
JPlotResp Output Per Stage

Data Management Workshop Foz do Iguassu- Brazil


Other quality control resources
Other Quality Control Resources

  • QC Forum collaborative web site:

    http://www.iris.edu/QCForum

  • General use QC mailing list:

    [email protected]

  • New Manual of Seismological Observatory Practice (NMSOP) from IASPEI:

    http://www.gfz-potsdam.de/bib/nmsop_formular.html

  • PQLX data analysis system (waveforms & PDFs):

    http://geohazards.cr.usgs.gov/staffweb/mcnamara/Software/PQLX.html

Data Management Workshop Foz do Iguassu- Brazil


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