This announcement is to inform the community of work by Data Services staff, sponsored by Instrumentation Services, to resolve inconsistencies and errors in datasets within the PH5 experiment archive. No action is required on your part unless you have questions about, or imminent interest in accessing data from, a specific PH5 experiment. Some PH5 experiment data are currently available through FDSN web services.

The NSF National Geophysical Facility data archive holds over 200 principal investigator-led PH5 experiments encompassing over 50,000 stations. Since the first PH5 experiments were archived nearly 20 years ago, PH5 has undergone significant development to support evolving seismic data types and enable data access through standard FDSN web services.

As we have continued to develop more sophisticated tools for extracting time series data from PH5 it has become clear that some of the historical data sets, most of which were submitted prior to 2018, contained a significant source of technical debt that needed to be addressed to meet current quality assurance standards. Over the past few months, Data Services staff have leveraged post-2020 expansions in PH5 capabilities to address known inconsistencies and errors in older PH5 experiments and bring affected datasets into better alignment with current PH5 standards. As part of this effort, additional data has become available from multiple experiments, channel orientation has been updated as needed, and response information has been verified and updated as needed.

These improvements have primarily addressed PH5 experiments with Texan (RT125/RT125A) and RT130 dataloggers borrowed for PASSCAL experiments from 2005–2018. Nearly all PH5 experiments for which both data collection and archival took place in this time range have been updated.

If you have any questions about your PH5 experiment(s) that may have been updated during this effort, please contact help@earthscope.org and include the assembled ID, network code, and PASSCAL experiment ID (if applicable) in your message.

Please also contact help@earthscope.org if you’re interested in accessing data from PH5 experiment(s) following the retirement of PH5 web services, or if you want to express interest in future SEGY data access through web services. There are ongoing additions to FDSN web services of experiment data formerly available through PH5 web services and you can continue to send requests for access.