Quality control system in seismology

USP Seismological Center developed a protocol for quality control (QC) of seismological data and stations operation status ensuring adequate performance of sensors and the best and most complete data archive. A set of variables acquired depending on the instruments used (Nanometrics, Guralp, Reftek on Knemetrics), are weekly monitored. Variables are chosen to guarantee the maximum uptime of stations, ensure the correct station configuration and optimization of onsite maintenance. Noise level is also monitored with the use of PQLX software (IRIS/PASSCAL), comparing changes to stations common probability density functions (PDF) over time. Collected information generate reports that are physically and digitally archived in a git repository and composes a rich set of information for field work planning. When any parameter change to a critical state, we open a git issue for a team member that will be responsible for verification and any needed correction. While the issue is open on the system, the QC operator accompanied it. On the data archive side, we compare the amount of stations link up-time with data completeness. Data collected during station maintenance builds up a duplicate archive that is usually most complete than real-time transmitted data. We also ensure that this archive is clean, with non redundant data. It is filled slowly with data from the real-time archive to form a final USP data archive. During the merge process, we label data extracted from the instrument using miniSeed flags that allows for later corrections that may be needed. Newly installed stations have its orientation verified using teleseismic data, and should not have an error greater than 5 o concerning the North Geographic orientation. In the three years that the system is in operation more than 600 calls have been opened, being half for internal processing and the other half is divided into data transmission problems, power failure problems and problems with damaged or vandalized sensors.