Data Services Newsletter

Volume 21 : No 1 : Spring 2019

Retirement of full SEED Data Volumes from IRIS DMC

This article is intended for individuals that are currently requesting “comprehensive” data files from the IRIS DMC that are requested using the BREQ_FAST request mechanism. If you have already migrated your workflow to the IRIS’s Web Services, you can go back to your coffee. If not, then we hope this article will provide you with the ability to do so by the end of calendar year 2019, when we anticipate ending support for generating full-SEED files in January 2020.

One important take away: by transitioning to using FDSN webservices for data access, you are most of the way down the path towards seamlessly collecting data from multiple data centers. From there it is a small step to the Federated Data Center Concept that will increase your ability to discover and access more data from globally distributed data centers that offer these baseline services.

Background:

A so-called “full SEED” volume is the combination of time series data along with comprehensive metadata. In essence a full SEED volume is the combination of miniSEED with a matching dataless volume in a single file.

SEED volumes were not designed for data processing and analysis, and are commonly converted to other formats prior to data processing. The IRIS DMC’s rdseed software (first introduced in 1988), which can convert full SEED volumes to many different output formats, is now retired with no anticipated maintenance.

Since 2015, FDSNWS (FDSN Web Services) have been the primary delivery mechanisms for data. These services and related tools increase data discoverability and access by leveraging a common access mechanism across seismological data centers.

Alternatives for common uses of full SEED:

  • For extracting metadata, use the fdsnws-station service The fdsnws-station web service returns station metadata in FDSN StationXML format or as delimited text. Results are available at multiple levels of granularity: network, station, channel and response. Metadata may be selected based on channel descriptors, time ranges, geographic regions, and more.
  • If you require dataless SEED, you can convert StationXML using the StationXML converter. This utility enables you to convert between StationXML and dataless, and dataless to StationXML.
  • If you ultimately require SAC files, miniSEED, plus optional metadata from the fdsnws-station service, can be created using our mseed2sac converter.
  • The FetchData tool downloads both miniSEED and the simple text metadata needed for conversion to SAC. FetchData can also download metadata in “RESP” and “SAC Poles and Zeros” formats.
  • If you need response information in “RESP” format you can get them directly from the irisws-resp web service.
  • If you need response information in “SAC Poles and Zeros” format you can get them directly from the irisws-sacpz web service.
  • As you transition from dataless SEED to StationXML, we also provide a StationXML validator to help become familiar with how to correctly create and read valid StationXML files, located here StationXML Validator. Documentation for usage, with examples, is located in the StationXML-validator-Wiki
  • If you still need rdseed-like capability you may try the Java port called jrdseed

We encourage you to try these new formats, and if you have questions or need help, we can provide assistance, using these role accounts. For general data access questions, send an email to engine_room@iris.washington.edu. If you have a more targeted webservice question, we suggest using the webservices@lists.ds.iris.edu mailing list.

Good luck with your research, and thank you for giving these new, improved, services your attention.

by Rick Benson (IRIS-DMC)

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