Federated Discovery of International Data Holdings using IRIS Web Tools
For the past five years, IRIS Data Services has been fostering the development of an international community of participating data repositories in providing seismic data and metadata using agreed-upon web service standards. Using the governance structure of the Federation of Digital Seismic Networks (FDSN), a set of documents were constructed and approved to serve as the basis for how data centers should expose customized user access to seismic waveform data, instrumentation metadata, and in some cases hypocenter catalogs. Termed FDSN Web Services, IRIS is now registering about 20 active data centers that are ready to provide data, which is tracked and stored in what IRIS calls the Fedcatalog. The Fedcatalog data is made available through a web service closely modeled on the existing FDSN web services, allowing federated data access to be easily integrated into existing tools and processes.
With a fast, easily accessible directory in the Fedcatalog, web tools for finding and exploring stations that were confined to only IRIS holdings can now stretch out to find information on a whole host of seismic instrumentation that cannot be found at IRIS, but are readily available at other institutions. The first tool to make this transition was GMAP, which has been greatly upgraded in the past year with a responsive look and feel and having the ability to plot all stations from all participating FDSN centers.
A very important tool to take advantage of this new world view is WILBER. Having already large scale event and station scanning capabilities, this new WILBER is capable of finding stations from other data centers and letting users sample and request data from those remote centers in their download!
Finally, a useful tool that has been serving instrumentation experts and seismologists for more than a decade is now expanding its reach. The MetaData Aggregator (MDA), a mainstay of station metadata discovery is now getting a completely new look and allows users to see stations that different data centers may have in common as well as letting users drill down to instrument response values from both IRIS and other active data centers worldwide. Currently in beta under the name MDA-2, this tool takes a fresh approach to navigating and finding just the station metadata needed and presenting links to formatted downloads as well as other informational web pages related to the station being viewed.
These federated tools are the product of many years of work with international data centers participating in the FDSN, building technologies to agreed-upon standards and maintaining independent data systems that can function as a coherent whole. Together, they form a single global database of acquired seismic knowledge ready for the latest challenges facing seismological study.
by Rob Casey (IRIS Data Management Center) , Adam Clark (IRIS DMC) , Nick Falco (IRIS DMC) and Mick Van Fossen (IRIS DMC)