FDSN webservices

The International Federation of Digital Seismograph Networks (FDSN) has defined web services for accessing waveform, station and event information. The FDSN specification is a standardized protocol allowing users to retrieve data and metadata through a widely used web protocol, such as the one you are using everyday to browse websites: the hypertext transfer protocol (http). Data centres adopting FDSN webservices, such as AusPass, IRIS, Orfeus or Geonet, are therefore able to offer their data in a consistent way. All programs accessing data via the FDSN web services are compatible with any data centre implementing FDSN interfaces.

How to access AusPass data


AusPass uses this address to support our archive service implementation: http://auspass.edu.au:8080.
The following FDSN webservices are available:

These services can be used via a URL query (URL builder: http://auspass.edu.au:8080/fdsnws/) or a client tool (e.g.: see our ObsPy tutorial).

Example

This example shows how to download the waveform data (in miniSEED format) recorded after the Samoa earthquake (29 September 2009 at 17h48) at BILBY stations in central Australia. In your browser, type:

http://auspass.edu.au:8080/fdsnws/dataselect/1/query?net=6F&sta=*&cha=BHZ&start=2009-09-29T17:50:00&end=2009-09-29T18:50:00

Element of the data request Meaning
http://auspass.edu.au:8080/ Server name (AusPass website serving data on port 8080)
fdsnws/FSDN Web Services on that server
dataselect/1/Data retrieval services (use "station/1/" to retrieve station metadata and "event/1/" for event metadata)
queryDo a download
? Marks the end of the website adress serving the data
&Separates the arguments to select AusPass data
net=6F Seismic network "6F" - BILBY
sta=* Select all stations in BILBY array, central Australia
cha=BHZVertical broadband channel (also available: BHN and BHE, all broadband channels can be selected with cha=BH?)
start=2009-09-29T17:50:00.000Data start time using ISO standard date and time format
end=2009-09-29T18:50:00.000Data end time using ISO standard date and time format



Recommendations


The AusPass team does its best to maintain fast and efficient webservices.

However, it is recommended not to request too much data in a single request. The larger the request, the longer it takes to complete. If a large request fails, it will have to be resubmitted. You can break a large request into smaller ones. Then, if a failure occurs, you will just have to resubmit the small request. Webservice connections can break if no data is transmitted after 5-10 minutes. Therefore, do not rely on requests that could take more than 5-10 minutes to begin returning data.

On the other hand, for performance reasons, do not to make lots of very small data requests. Be aware that every time a request is made, a new connection is established and the associated processing overhead will slow the response.

Best practice is to group requests by time period (one request for several stations, but one time period - see above example) or station (one request for several time periods, but one station).

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