Portable Broadband Seismic Stations - Checking Data Quality Cairo, Egypt November, 2009 Noel Barstow Bruce Beaudoin Marcos Alvarez.
Post on 16-Jan-2016
Portable Broadband Seismic Stations - Checking Data QualityCairo, EgyptNovember, 2009Noel BarstowBruce BeaudoinMarcos Alvarez
Checking Data QualityKeep good records of everything
> Before going to the fieldTest all Instrumentation and Cables
> 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
> In the labArchive, Analyze, and Document Data
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
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
Electronic Calibrations: Corner Period Damping
Do the signals look the same?close up of verticalsoverlay surface wave
Nightly Plots of Pier Tests
Electronic Step Calibration
White Noise CalibrationsInput White Noise Phase AmplitudeSensor OutputSensitivity
Vertical ComponentsPier Data Comparing Sensor Noise of Different Sensor Types
STS-2 Element Contribution to SignalEastNorthVertical
STS-2 Element V problemZNE Noisy SensorZNE
Triaxial SystemsReferenceUnfiltered EarthquakeFiltered 10 -30 sec periodZNEZNETest Sensor: Drift & DC offset
Guralp CMG-3TOrthogonal elements2 Horizontal1 Vertical
Replace Bent 3T PivotComparing Reference and Problem SensorBeforeAfter Time Scale = 3 hoursEast / West Component
Spectra Sudden Noise on Guralp 3T Vertical ComponentNoise beginsNoisy SpectraDays:1234Vertical DataLocking and Unlocking the 3T provides a temporary fix
Amplitude change at DC offsetTime = 8 DaysN/SE/W ZAmplitude Problem: Loss of Differential OutputDas, Sensor, or interconnecting Cables could be the cause
Data QC & 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
Data Archiving Support PASSCAL acts as an intermediary between PASSCAL Investigators and the DMC
Check completeness of data submitted to PASSCALHelp evaluate or fix timingVerify SEED FormatEnsure agreement between data and metadataCheck completeness of data submitted to DMC
TroubleshootingPASSCAL provides email and phone support for our users before, during, and after experiments to analyze specific problems.
PASSCAL staff members are available for the initial testing and installation phase of field campaigns.
Typically there are over 500 broadband and short-period PASSCAL stations deployed at any given time.
Contact us: firstname.lastname@example.org
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
Review Stations StatusFirmwareVoltsGPSTimingTime Scale = 1 WEEKlogpeekPlot of StationLog MessagesFromRT130 DAS
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.