GSN QC at the IRIS DMC Mary Templeton GSN Coordination Meeting Seattle, WA November 16, 2011

GSN QC at the DMC Began July 1, 2011 Looking to optimize 1/2 FTE Charges so far –Do what you do for US-REF –Extra attention to metadata –In situ response monitoring

Routine QC and Reporting Draft weekly report –In the internal feedback stage –Reference Network approach –report current problems to network operators

Report Content Current and recently resolved outages Real-time telemetry issues Excessive gap list Archive status of non-real-time stations Timing issues Instrumentation or site issues Metadata issues

Attention to Metadata Location Orientation Instrument type –Response –Instrument comment Sample rate –Channel (B052) –MiniSEED fixed section –Response high f c –Response cascade final sample rate

Metadata Consistency Checking Response checking –Evalresp SEED conformance Sensitivity (f norm in passband) Units FIR delays –Visual inspection

Metadata Consistency Checking Do changes that correspond to epoch changes agree for all appropriate SNCLs? –Epoch start/end times –Sensor or datalogger sensitivity –Pole/zero or FIR cascade

In Situ Response Monitoring The problem: find a way to see frequency-dependent STS-1 response changes reported by the Waveform Quality Center at the DMC. “In situ” - monitoring methods not requiring remote or local instrument control.

Ideal Method(s) assess single, as well as coincident sensors apply to vertical and horizontal channels measure amplitude and phase errors periods from 2t to at least 250s

Ideal Method(s) separate response issues from other amplitude issues (noise, model limitations, hardware performance) –strong correlation or coherence for synthetic or coincident sensor comparisons –“known” signal for single-sensor techniques redundant measurements at period(s) of interest

Techniques in Use TechniqueSensorsChannelsAmp/PhasePeriods Earth Tide syntheticssingleZ (all?)both44712s Event synthetics (WQC)singleallamplitude 2t-400s Event cross-spectracoincidentallbothcommon passband Microseism cross-specracoincidentallboth~7s PSD/PDF tools (DMC)singleallamplitude 2t S 0 normal modessingleZ (all?)both s

Recommendations Prototype cross-spectra of coincident sensors

Mw=6.9 Sikkim, India (9/18/11) Cross-spectra

Recommendations Prototype cross-spectra of coincident sensors Evaluate what it would take to incorporate Princeton synthetics comparison

Recommendations Prototype cross-spectra of coincident sensors Evaluate what it would take to incorporate Princeton synthetics comparison Add ocean loading to existing tidal synthetics at the DMC

Recommendations Prototype cross-spectra of coincident sensors Evaluate what it would take to incorporate Princeton synthetics comparison Add ocean loading to existing tidal synthetics at the DMC Calculate PSDs over period range appropriate to sensor passband

Recommendations Prototype cross-spectra of coincident sensors Evaluate what it would take to incorporate Princeton synthetics comparison Add ocean loading to existing tidal synthetics at the DMC Calculate PSDs over T range appropriate to sensor passband Make calculated traces available to users

Mw=6.9 Sikkim, India (9/18/11) Cross-spectra (Davis)