Does IRIS perform quality assurance on the data it receives?
Yes. IRIS DMC has the MUSTANG system to perform metrics-based quality assurance logging on its archived datasets.
With MUSTANG, you can query for statistics by network and station as well as by a span of time, using simple-to-use web service URLs. Also available are Power Spectral Densities (PSD) and Probability Density Functions (PDF) as both plots and text output.
MUSTANG also provides a gallery browser, called PDF browser, for looking at PDFs and PDF-mode spectrograms of networks over many different spans of time.
Please visit http://service.iris.edu/mustang to get the details on the services offered and links to clients that use MUSTANG.