1. ASL QC Procedures Status and plans

2. GSN ANSS Traditional Waveform Review  The “morning run” Daily email summarizes problems with availability, timing, and various data integrity values. Quick review of all LH waveform data for the previous 24 hours, PSD’s reviewed as needed  Weekly review Similar to the morning run, but based on a 7-day dataset  Earth-tide comparison Quick way to identify polarity issues and egregious gain errors These traditional tools allow us to verify the short-term state-of- health of the network and identify most problems ….

3. GSN ANSS QAPs were swapped QDP was swapped Traditional Waveform Review ….however they do not catch everything

4. GSN ANSS Data Quality Analyzer The ASL has implemented several new tools to expand their capabilities

5. GSN ANSS Data Quality Analyzer – current parameters Record parameters  Data availability  Number of Gaps  Timing quality Noise parameters  Channel noise levels are measured with respect to a baseline  Sampled at 4-8, 18-22, 90-110 and 200-400 s Coherence and Power difference  Calculated at sites with 2 broadband sensors  Sampled at 4-8, 18-22, 90-110 and 200-400 s Calibration parameters  Days since last calibration  Mean amplitude error between the calibration & current metadata as measured in the flat part of the response  Mean amplitude error between the calibration & current metadata as measured at the long period corner Data Quality Analyzer

6. GSN ANSS Data Quality Analyzer – future parameters Noise parameters, coherence, and power difference at 1-5 Hz Noise values with respect to an absolute scale, as such as USGS low noise model or the GSN noise model Mass position values or some derived parameter thereof Comparison of the latest calibration to the nominal response in terms of the corner and flat part of the spectrum Orientation differences for sites with two broadband sensors Event windows, capturing station information for each major quake Data Quality Analyzer

7. GSN ANSS Event-based Review With one plot we can identify response, timing, gains and polarity issues Left: KIP for an event in 2007 Right: HIA for a 2011 event

8. GSN ANSS Event-based Review  Generating synthetics for all events with CMTs M> 6.5 Multiple methods being explored  Long period: Princeton 3-D, Normal mode 1-D, W-phase  Shorter period: Herrmann’s wavenumber integration  Waveform comparison between both broad-band sensors and low-gain accelerometer data  Azimuth evaluation Differential & absolute

9. GSN ANSS ASL QC On-going Projects  Calibration analysis Processing for the long-period corner moving forward Processing for the high-frequency corner awaiting implementation  SensOrLoc processing Determination of orientation and absolute calibration Performed during site visits Values propagated backwards where applicable  Pre-deployment checks Thorough review of station performance prior to deployment Integration testing and review of equipment  Station Certification Using all tools at our disposal, review each station epoch verifying gain, lp-corner and orientation, updating metadata where needed

10. GSN ANSS ASL QC Procedures summary  Daily waveform review Earth-tide comparison  Data Quality Analyzer Customizable format  Event-based review Synthetics Intra-sensor comparisons  Problem tracking Using Report Tracker “RT” ticket system Working with the field engineers to solve problems  Problem reporting “Station issues” tab on the Network operations Web pages Data Problem Reports (DPRs)

11. GSN ANSS References Hutt, C. R. and A. T. Ringler (2011). Some possible causes of and corrections for STS-1 gain changes in the Global Seismographic Network, Seismological Research Letters, 82, 484-495. McNamara, D. E., C. R. Hutt, L. S. Gee, H. M. Benz, and R. P. Buland (2009). A Method to Establish Seismic Noise Baselines for Automated Station Assessment, Seismological Research Letters, 80, 628 - 637, 2009. Ringler, A. T., L. S. Gee, C. R. Hutt, and D. E. McNamara (2010). Temporal variations in global seismic station ambient noise power levels, Seismological Research Letters, 81,605–613. Ringler, A. T., C. R. Hutt, R. Aster, H. Bolton, L. S. Gee, and T. Storm (2012). Estimating pole/zero errors in GSN-IRIS/USGS network calibration metadata, Bulletin of the Seismological Society of America, in press. Ringler, A. T., L. S. Gee, B. Marshall, and C. R. Hutt (2011). Data quality of seismic records from the Tohoku, Japan, earthquake as recorded across the Albuquerque Seismological Laboratory Networks, Seismological Research Letters, in review. Ringler., A. T., J. D. Edwards, C. R. Hutt, and F. Shelly (2011). Relative azimuth inversion by way of damped maximum correlation estimates, Computers and Geosciences, in review.

12. GSN ANSS Calibrated Channel, time, duration: KIP 00 BHZ 2011 306 03 40 16 9999-14400 Cal Analysis Date: 2011,308 Software Version: 2.01 Instrument: STS1VBBE3 # # Best Fit Amplitude Error (dB): 0.014383 Best Fit Phase Error (degree): 0.18542 Nominal Amplitude Error (dB): 0.041388 Nominal Phase Error (degree): 0.24889 # # Existing RESP info B050F03 Station: KIP B050F16 Network: IU B052F03 Location: 00 B052F04 Channel: BHZ B052F22 Start date: 2010,281,19:16:59 B052F23 End date: No Ending Time # Old Response Values Here (removed for clarity) # New Response Values Here (removed for clarity) # old BHZ A0: 3.948470E+03 new BHZ A0: 3.947835E+03 # # old VHZ A0: 3.975050E+03 new VHZ A0: 3.989613E+03 Calibration Analysis