Data Services Newsletter

Volume 20 : No 3 : Winter 2018

The New SeisComP3 Waveform Availability Service

SeisComP31 is a utility created developed by the GEOFON Program at Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, and gempa GmbH that has had considerable reach with end users and data centers around the globe for the past decade. The SeisComP3 website describes this software as serving the needs of “data acquisition, processing, distribution and interactive analysis.”2

It is a complex but flexible environment that provides database and waveform file access to seismic data, utilities for archiving and retrieval of seismic data, and graphical user interface tools for visualization and mapping capabilities. Most importantly, SeisComP3 can run as a data server to allow external user access to datasets that it stores, through SeedLink, ArcLink, and FDSN web service interfaces.3

FDSN web services are gaining in popularity of use and serve to form a federation of data centers around the world.4 Currently, SeisComP3 provides the three primary functions of a fully functional FDSN web service suite: station metadata queries (fdsnws/station), selection of time series waveforms (fdsnws/dataselect), and searches for earthquake hypocenters (fdsnws/event).

A more recent web service capability that is in full operation at IRIS DMC is called the ‘Availability’ service,5 which provides users access to both high level queries for time extents of data from different stations, but also detailed queries on individual channels, showing available times down to the sample. Providing this information requires an extensive time-tagging catalog that is generated by scanning each seismic data record in detail. This level of capability provides an additional guide for users and other automated systems to discover exactly what data is present at a given data center.

The value of this capability motivated IRIS to establish a work agreement with the SeisComP3 developers to add this web service to SeisComP3. The result is a new utility (scardac) that scans datasets within a SeisComP3 archive and creates a database of data extent and segment information as well as a new web service listed as an FDSN extension to allow this database to be queried (fdsnws/ext/availability). This capability has been added as of release ‘2018.327’.6

A data center utilizing the latest SeisComP3 can now easily provide a detailed manifest of their data holdings. It is the hope of IRIS that we can petition the FDSN working groups to accept this important metadata feature as a fourth entry to the standard FDSN web service contingent.

References:
1. Weber, Bernd & Becker, Jan & Hanka, Winfried & Heinloo, Anders & Hoffmann, M & Kraft, Toni & Pahlke, Doreen & Reinhardt, Jörg & Saul, Joachim & Thoms, H. (2007). SeisComP3 – Automatic and Interactive Real Time Data Processing.
2. SeisComP3 home page: https://www.seiscomp3.org/
3. FDSN Web Services: http://www.fdsn.org/webservices/
4. Data centers supporting FDSN Web Services: http://www.fdsn.org/webservices/datacenters/
5. IRIS Availability web service: https://service.iris.edu/irisws/availability/1/
6. SeisComP3 github page: https://github.com/SeisComP3/seiscomp3

by Rob Casey (IRIS Data Management Center)

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