Data Services Newsletter

Volume 22 : No 1 : Spring 2020

MUSTANG Metrics for PH5-format Data at the IRIS DMC

MUSTANG quality assurance metrics are now available for seismic data stored at the IRIS DMC in PASSCAL’s PH5-format. This growing data archive currently includes 110 active source and nodal experiments from years 2005-2020 and is accessible through web services at http://service.iris.edu/ph5ws. You can view a text listing of all PH5 experiments at IRIS here: PH5 experiments.

MUSTANG metric calculations begin within a few days after data for an experiment arrives at IRIS and results are available shortly thereafter. They are also recalculated in the event that experiment data is resubmitted and/or metadata is updated, so that they accurately reflect what is currently in the archive. These metrics are intended to provide Principal Investigators with valuable quality information about their experiment, while also being made available to all MUSTANG users.

Available Metrics for PH5

MUSTANG metrics span amplitude statistics (e.g., maximum, minimum, median, mean, root-mean-square variance values by day), data availability (e.g., percent availability, number of gaps, maximum gap length values by day), Power Spectral Densities (PSD), Probability Density Functions (PDF), and more. Most of the metrics that are available for miniSEED data at IRIS are also available for PH5 data, dependent on instrument type. Exceptions include the data latency metrics which are exclusive to near-real-time data and the prototype availability metrics that are calculated on-demand using information from the fdsnws availability web service (e.g., ts_percent_availability, ts_num_gaps_total). We intend to expand these on-demand availability metrics to include PH5 data in the future. Also of note are the set of metrics based on counts of miniSEED flags; because the PH5-format does not store these flags, these metrics will always return a value of 0 for PH5 data.

noise-spectrogram
noise-spectrogram plot for YW.1001..DPZ.D (IRIS Community Wavefield Experiment in Oklahoma, 2016)

Accessing MUSTANG metrics for PH5

The introductory page for MUSTANG is http://service.iris.edu/mustang. This is where users can find an overview of MUSTANG and descriptions of the six web services that return MUSTANG metrics and/or plots:

  • measurements – The measurements web service is where most data quality metrics can be accessed. Formats include XML, CSV, text, JSON, and JSONP.
  • noise-psd – The noise-psd service returns PSD values and plots.
  • noise-pdf – The noise-pdf service returns PDF values, plots, and statistics.
  • noise-mode-timeseries – The noise-mode-timeseries service returns daily PDF-mode values and timeline plots for selected frequencies.
  • noise-spectrogram – The noise-spectrogram service returns spectrogram-style plots of daily PDF-mode values.
  • noise-pdf-browser – The noise-pdf-browser service returns browsable views of PDF or spectrogram plots for multiple stations and/or multiple time periods. It also returns a list of station-channels-locations and time ranges that have available PSD/PDF values.

When accessing metrics for PH5-format data through these web services, it is important to know that the data quality code is “D” for this data. The requested quality code can be wild-carded as “*” or “?” to retrieve all qualities. In addition, the measurements web service does not require a quality code and will retrieve all qualities if not specified.

MUSTANG Client Visualization Tools and PH5

There are several web-based tools available for visualizing MUSTANG metrics, with varying compatibility for displaying PH5 metrics.

  • MUSTANG Databrowser – The MUSTANG Databrowser offers general plots, boxplots, gap duration plots, and more. It is fully compatible with displaying metrics for PH5 data. Because the available network-station-location-channel lists are populated based on metadata time spans, it is recommended to select a start and end time prior to selecting a PH5 experiment network.
  • LASSO – The Latest Assessment of Seismic Station Observations (LASSO) ranks stations according to metric values or customizable groups of metrics. While its “Basic” tab is not compatible with PH5 data, the “Advanced” tab allows for the selection of PH5 experiments.
  • MUSTANGularMUSTANGular plots color-coded metric values on a map. At this time, MUSTANGular cannot plot metrics for PH5 data but this functionality will be available in the near future.

by Gillian Sharer , Autumn Johnson , Laura Keyson and Mary Templeton (IRIS Data Management Center)

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