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

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

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

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

Do the signals look the same? close up of verticals overlay surface wave

Nightly Plots of Pier Tests

Electronic Step Calibration

White Noise Calibrations Input White Noise Phase Amplitude Sensor Output Sensitivity

Pier Data Comparing Sensor Noise of Different Sensor Types Vertical Components

Streckeisen STS-2

STS-2 Element Contribution to Signal East North Vertical

STS-2 Element V problem Z N E Noisy Sensor ZNEZNE

Triaxial Systems Reference Unfiltered EarthquakeFiltered sec period ZNEZNE ZNEZNE Test Sensor: Drift & DC offset

Orthogonal elements 2 Horizontal 1 Vertical Guralp CMG-3T

Replace Bent 3T Pivot Comparing Reference and Problem Sensor Before After Time Scale = 3 hours East / West Component

Sudden Noise on Guralp 3T Vertical Component Noise begins Noisy Spectra Days: Vertical Data Spectra Locking and Unlocking the 3T provides a temporary fix

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

PASSCAL develops and maintains software to extract data from the dataloggers, perform in-field quality checks, and manipulate the waveforms into archive formats. ftp.passcal.nmt.edu Data QC & Software

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

PASSCAL provides 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: Troubleshooting

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

Review Station’s Status Firmware Volts GPS Timing Time Scale = 1 WEEK ‘logpeek’ Plot of Station Log Messages From RT130 DAS