Portable Broadband Seismic Stations - Checking Data Quality Cairo, Egypt November, 2009 Noel Barstow Bruce Beaudoin Marcos Alvarez

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<ul><li><p>Portable Broadband Seismic Stations - Checking Data QualityCairo, EgyptNovember, 2009Noel BarstowBruce BeaudoinMarcos Alvarez</p></li><li><p>Checking Data QualityKeep good records of everything</p><p>&gt; Before going to the fieldTest all Instrumentation and Cables</p><p>&gt; In the fieldInstall Station and Check: Power, Timing, Sensor Orientation, SignalVisit stand-alone stations frequently to: Download Data and Review Station Status and Metadata on site</p><p>&gt; In the labArchive, Analyze, and Document Data </p></li><li><p>Hardware Maintenance and QC: DataloggersFunction test all Dataloggers prior to shipment:Bit weight, oscillator drift, data time stampsKeep maintenance records in an electronic databaseTest and upgrade firmware when necessary </p></li><li><p>PASSCALs Hardware Maintenance: SeismometersFeedback seismometers are Pier-Tested for 4-7 Days and compared to a Reference Sensor:- Amplitude and Phase Polarity Spectral Content Noise Characteristics</p><p>Electronic Calibrations: Corner Period Damping</p></li><li><p>Do the signals look the same?close up of verticalsoverlay surface wave</p></li><li><p>Nightly Plots of Pier Tests</p></li><li><p>Electronic Step Calibration</p></li><li><p>White Noise CalibrationsInput White Noise Phase AmplitudeSensor OutputSensitivity</p></li><li><p>Vertical ComponentsPier Data Comparing Sensor Noise of Different Sensor Types </p></li><li><p>Streckeisen STS-2</p></li><li><p>STS-2 Element Contribution to SignalEastNorthVertical</p></li><li><p>STS-2 Element V problemZNE Noisy SensorZNE</p></li><li><p>Triaxial SystemsReferenceUnfiltered EarthquakeFiltered 10 -30 sec periodZNEZNETest Sensor: Drift &amp; DC offset</p></li><li><p>Guralp CMG-3TOrthogonal elements2 Horizontal1 Vertical</p></li><li><p>Replace Bent 3T PivotComparing Reference and Problem SensorBeforeAfter Time Scale = 3 hoursEast / West Component</p></li><li><p> Spectra Sudden Noise on Guralp 3T Vertical ComponentNoise beginsNoisy SpectraDays:1234Vertical DataLocking and Unlocking the 3T provides a temporary fix</p></li><li><p>Amplitude change at DC offsetTime = 8 DaysN/SE/W ZAmplitude Problem: Loss of Differential OutputDas, Sensor, or interconnecting Cables could be the cause </p></li><li><p>Data QC &amp; SoftwarePASSCAL develops and maintains software to extract data from the dataloggers, perform in-field quality checks, and manipulate the waveforms into archive formats.http://www.passcal.nmt.eduftp.passcal.nmt.edu</p></li><li><p>Data Archiving Support PASSCAL acts as an intermediary between PASSCAL Investigators and the DMC</p><p>Check completeness of data submitted to PASSCALHelp evaluate or fix timingVerify SEED FormatEnsure agreement between data and metadataCheck completeness of data submitted to DMC</p></li><li><p>TroubleshootingPASSCAL provides email and phone support for our users before, during, and after experiments to analyze specific problems. </p><p>PASSCAL staff members are available for the initial testing and installation phase of field campaigns.</p><p>Typically there are over 500 broadband and short-period PASSCAL stations deployed at any given time.</p><p>Contact us: passcal@passcal.nmt.edu</p></li><li><p>After the power point presentationLive demonstration oflogpeek - plotting of RT130 station log messagespql - PASSCAL Quick Look - to view waveforms, fast fourier spectrum, split view, etc. pql will read mini-seed, sac, and segy formats</p></li><li><p>Review Stations StatusFirmwareVoltsGPSTimingTime Scale = 1 WEEKlogpeekPlot of StationLog MessagesFromRT130 DAS</p><p>Another example of a noisy STS-2. This one is showing a problem with Element V (expanded in the bottom frame).5. Loss of Differential output - N/S component - Diff signalling is transmitted by 2 complementary signals on 2 separate, balanced wires, often twisted pairs. The advantages of of the complementary signals are: 1) Increased resistance to electro-magnetic interferenceAnd 2) Greater tolerance to Grounding Offsets.</p></li></ul>