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June 30th, 2014
The NCEDC is pleased to announce a new NCEDC web service for retrieving event-associated time series from the NCEDC. Web services provide simple functions that can be used from a web browser, command-line programs such as curl and wget, dedicated clients, and through programming languages such as perl, python, shell scripts, or MATLAB.
The ncedc-eventdata web service returns miniSEED time series data for the specified event from the specified earthquake catalog. In it simplest form, it returns the time series for all channels and time intervals that have been associated with the event at the NCEDC. This web services provides a functional replacement for the email-base EVT-FAST service.
Using the GET method, you can optionally restrict which data channels to retrieve by specifying a (wildcarded) selection of SEED Network, Station, Location, and Channel names, and an optional start time and end time for the time series. Using the POST method, you can specify a list of (wildcarded) channel names, a global restricted time window, and specific restricted time window for each specified channel. Each ncedc-eventdata web service request can only request data for a single event. You can easily generate and submit ncedc-eventdata requests using command line programs such as wget, curl, MATLAB, or dedicated client programs provided by the NCEDC.
Client programs for the ncedc-eventdata web service
The program FetchEventData is a command-line fetch script that uses the ncedc-eventdata service to event-associated time series for the specified eventid from the specified catalog. Its command-line options provide support for all of the ncedc-eventdata selection options.
The program mssplit is used to split a stream of MiniSEED records into a separate file for each data channel. It can optionally create a new directory for these data files. It can read data from either from a file or from stdin.
FetchEventData -E 72099881 -C NCSS | mssplit -D NCSS.72099881
Will retrieve all time series data for the eventid 72099881 in the NCSS catalog, create a directory named NCSS.72099881, and save each data channel in a file named with the station, network, channel, location, and start time in the specified directory.
FetchEventData -E 72099881 -C NCSS -o msfile ; mssplit -D NCSS.72099881 msfile
Will retrieve all time series data for the eventid 72099881 in the NCSS catalog, saving all data channels info a file name msfile. The mssplit program then splits the specified MiniSEED file into separate channel files in the specified directory.
Why web services?
Web services at the NCEDC use a RESTful (Representational State Transfer) design to provide a simple stateless query and data retrieval system. RESTful Web services use the HTTP protocol and normally communicate with clients using TCP port 80, which is the default port used by web servers. Using HTTP and standard web server ports minimizes interference from firewalls, and allows you to use web services anywhere you can use a web browser -- from behind most firewalls, and through web proxies.
Please visit the NCEDC Web Services Web Page for a complete list of NCEDC Web services and descriptions.