Data Quality Assurance


The Quality Assurance (QA) team at the IRIS DMC is tasked with monitoring the quality of the IRIS DMC seismic data archive and providing resources relating to data quality to the earth science community. On this page you will find information on general QA practices, MUSTANG metrics and PDFs, and links to QA related products and services at the DMC.

Quality Assurance Mission Statement

QA Related Web Services, Products, and Software

Web Services and Client Tools

MUSTANG, Modular Utility for Statistical Knowledge Gathering: seismic data quality metrics and Probability Density Functions (PDFs).


Synthetic Seismograms
Global ShakeMovie synthetics at the DMC
Global ShakeMovie synthetics at the DMC event listing

Envelope Functions

Calibration Products


R Package on CRAN, IRISMustangMetrics is the official public release of R code used by MUSTANG to calculate metrics.
ISPAQ, software for calculating MUSTANG-style seismic data quality metrics on a local machine.
PQLX, open-source software seismic trace and PDF viewer.

Other Resources

Data Problem Reports – search submitted data problem reports by station and network. This is not an exhaustive listing of all data problems that may exist in the archive.

QA of USArray Data


  • (2020-06-23) We are pleased to announce the addition of three new metrics to MUSTANG: max_range, sample_rate_channel, and sample_rate_resp. We are now computing these metrics for incoming data and have begun the process of calculating values back through the data archive. Full descriptions of these metrics can be found at these links:

max_range: calculates the difference between the largest and smallest sample value in a 5 minute rolling window and returns the largest value encountered within a 24-hour timespan.

sample_rate_channel: A boolean measurement that returns 0 if miniSEED and channel sample rates agree within 1%, or 1 if they disagree.

sample_rate_resp: A boolean measurement that returns 0 if miniSEED and response-derived sample rates agree within 15%, or 1 if they disagrees.

  • (2020-01-14) We have released a new MUSTANG Databrowser ( version that has the following improvements:
    1. The drop down network-station-location-channel lists now include experiments stored in our PH5-format archive. We have good metric measurement coverage for PH5 experiments from 2017-2019 and we are working backwards in time to calculate metrics for experiments from 2005-2016.
    2. The “gap duration” plot type now has a fourth plot added. The plots included in this view are: gap duration vs. date, gap duration vs. time of day, a histogram of gap durations, and number of gaps vs. time.
    3. The PDF noise mode spectrogram plot now has the same default color scale limits (plot.powerscale.autorange=0.9) as the spectrogram web service (

Citations and DOIs

To cite the MUSTANG system or reference the use of MUSTANG metrics:

  • Assuring the Quality of IRIS Data with MUSTANG
    Robert Casey, Mary E. Templeton, Gillian Sharer, Laura Keyson, Bruce R. Weertman, Tim Ahern
    Seismological Research Letters (2018) 89 (2A): 630-639.

Contact Us

There is a Message Center List available to provide a forum for QA discussion by the community (subscription required):

And a Message Center List for MUSTANG-related announcements (including service outages and downtimes, etc.):

Issues regarding Quality Assurance at the IRIS DMC can be addressed to this Message Center List :

IRIS DMC QA Staff can be contacted directly at:

Frequently Answered Questions

There are currently 5 Quality Assurance related questions:


There are currently 4 Quality Assurance tutorials:

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