Seismic Quality Assurance Rick Benson IRIS DMC August

Seismic Quality Assurance Rick Benson IRIS DMC August 13 -19, 2010 Data Management Workshop Foz do Iguassu- Brazil

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 August 13 -19, 2010 Data Management Workshop Foz do Iguassu- Brazil

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. August 13 -19, 2010 Data Management Workshop Foz do Iguassu- Brazil

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. August 13 -19, 2010 Data Management Workshop Foz do Iguassu- Brazil

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: 0º N out Z out 270º 90º All in phase E out Aleutian Island event : : Texas, USA station (BA: ~317°) 180º * Assumes Z component polarity is correct. August 13 -19, 2010 Data Management Workshop Foz do Iguassu- Brazil

Automated QC at the DMC Quality 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 August 13 -19, 2010 Data Management Workshop Foz do Iguassu- Brazil

Tracking Signal RMS August 13 -19, 2010 Data Management Workshop Foz do Iguassu- Brazil

Daily RMS Indicates Problems August 13 -19, 2010 Data Management Workshop Foz do Iguassu- Brazil

Tracking Signal Mean August 13 -19, 2010 Data Management Workshop Foz do Iguassu- Brazil

Tracking Data Flow August 13 -19, 2010 Data Management Workshop Foz do Iguassu- Brazil

Tracking STA/LTA Values August 13 -19, 2010 Data Management Workshop Foz do Iguassu- Brazil

PDF of Power Spectral Density August 13 -19, 2010 Data Management Workshop Foz do Iguassu- Brazil

Clickable PDFs to Find Time Dependencies August 13 -19, 2010 Data Management Workshop Foz do Iguassu- Brazil

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/S oftware/PDFSA. html • PDFs calculated daily for real-time data received at the IRIS-DMC, stored in database August 13 -19, 2010 Data Management Workshop Foz do Iguassu- Brazil

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) Nov 8 -17, 2009 Data Management Workshop Foz do Iguassu- Brazil

Tide Comparison at IU. SAML August 13 -19, 2010 Data Management Workshop Foz do Iguassu- Brazil

Tide Comparison at TA. H 02 A August 13 -19, 2010 Data Management Workshop Foz do Iguassu- Brazil

Tide Comparison at PR. ICM August 13 -19, 2010 Data Management Workshop Foz do Iguassu- Brazil

Tide Comparison Without Response Information August 13 -19, 2010 Data Management Workshop Foz do Iguassu- Brazil

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 August 13 -19, 2010 Data Management Workshop Foz do Iguassu- Brazil

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 August 13 -19, 2010 Data Management Workshop Foz do Iguassu- Brazil

verseed example output August 13 -19, 2010 Data Management Workshop Foz do Iguassu- Brazil

Other verseed Examples August 13 -19, 2010 Data Management Workshop Foz do Iguassu- Brazil

SEED Response Evaluation evalresp - evaluates system amplitude and phase response using SEED RESP format. C program that runs on Solaris, Linux & Mac OSX. JEval. Resp - Java version of evalresp, runs anywhere Java is available. Reads either SEED RESP format or fetches response information from a DHI server. JPlot. Resp - 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. August 13 -19, 2010 Data Management Workshop Foz do Iguassu- Brazil

JPlot. Resp Usage August 13 -19, 2010 Data Management Workshop Foz do Iguassu- Brazil

JPlot. Resp Console August 13 -19, 2010 Data Management Workshop Foz do Iguassu- Brazil. Data

JPlot. Resp Output August 13 -19, 2010 Data Management Workshop Foz do Iguassu- Brazil

JPlot. Resp Output Per Stage August 13 -19, 2010 Data Management Workshop Foz do Iguassu- Brazil

Other Quality Control Resources • QC Forum collaborative web site: http: //www. iris. edu/QCForum • General use QC mailing list: qc-issues@iris. washington. edu • 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 August 13 -19, 2010 Data Management Workshop Foz do Iguassu- Brazil