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Published byPatricia Houston Modified over 9 years ago
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Portable Broadband Seismic Stations - Checking Data Quality Cairo, Egypt November, 2009 Noel Barstow Bruce Beaudoin Marcos Alvarez
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Checking Data Quality Keep good records of everything > Before going to the field Test all Instrumentation and Cables > In the field Install Station and Check: Power, Timing, Sensor Orientation, Signal Visit stand-alone stations frequently to: Download Data and Review Station Status and Metadata on site > In the lab Archive, Analyze, and Document Data
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Hardware Maintenance and QC: Dataloggers Function test all Dataloggers prior to shipment: Bit weight, oscillator drift, data time stamps Keep maintenance records in an electronic database Test and upgrade firmware when necessary
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PASSCAL’s Hardware Maintenance: Seismometers Feedback 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
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Do the signals look the same? close up of verticals overlay surface wave
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Nightly Plots of Pier Tests
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Electronic Step Calibration
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White Noise Calibrations Input White Noise Phase Amplitude Sensor Output Sensitivity
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Pier Data Comparing Sensor Noise of Different Sensor Types Vertical Components
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Streckeisen STS-2
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STS-2 Element Contribution to Signal East North Vertical
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STS-2 Element V problem Z N E Noisy Sensor ZNEZNE
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Triaxial Systems Reference Unfiltered EarthquakeFiltered 10 -30 sec period ZNEZNE ZNEZNE Test Sensor: Drift & DC offset
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Orthogonal elements 2 Horizontal 1 Vertical Guralp CMG-3T
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Replace Bent 3T Pivot Comparing Reference and Problem Sensor Before After Time Scale = 3 hours East / West Component
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Sudden Noise on Guralp 3T Vertical Component Noise begins Noisy Spectra Days: 1 2 3 4 Vertical Data Spectra Locking and Unlocking the 3T provides a temporary fix
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Amplitude change at DC offset Time = 8 Days N/S E/W Z Amplitude Problem: Loss of Differential Output Das, Sensor, or interconnecting Cables could be the cause
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PASSCAL 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.edu ftp.passcal.nmt.edu Data QC & Software
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Data Archiving Support PASSCAL acts as an intermediary between PASSCAL Investigators and the DMC Check completeness of data submitted to PASSCAL Help evaluate or fix timing Verify SEED Format Ensure agreement between data and metadata Check completeness of data submitted to DMC
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PASSCAL 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: passcal@passcal.nmt.edu Troubleshooting
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After the power point presentation Live demonstration of logpeek - plotting of RT130 station log messages pql - PASSCAL Quick Look - to view waveforms, fast fourier spectrum, split view, etc. pql will read mini-seed, sac, and segy formats
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Review Station’s Status Firmware Volts GPS Timing Time Scale = 1 WEEK ‘logpeek’ Plot of Station Log Messages From RT130 DAS
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