An explanation of the CQSRG IRIS DMC Seismogram Download Process

Here is a brief explanation of how the CQSRG IRIS DMC Seismogram Download web page services your request.

Parameters for the IRIS DMC webservice request query

Parameter	Alias	Support	Default	Allowed values	Type	Unit
starttime	start	required	[Any]	Any valid time	time	UTC
	Limit results to time series samples on or before the specified end time.
endtime	end	required	[Any]	Any valid time	time	UTC
	Limit results to time series samples on or after the specified start time.
network	net	required	[Any]	Valid network code or wildcard	string
	Select one or more network codes. Can be SEED network codes or data center defined codes. Multiple codes arecomma-separated.
station	sta	required	[Any]	Valid station code or wildcard	string
	Select one or more SEED station codes. Multiple codes are comma-separated.
location	loc	required	[Any]	Valid location code or wildcard	string
	Select one or more SEED location identifiers. Multiple identifiers are comma-separated. As a special case '--' (two dashes) will be translated to a string of two space characters to match blank location IDs.
channel	cha	required	[Any]	Valid channel code or wildcard	string
	Select one or more SEED channel codes. Multiple codes are comma-separated.
quality		optional	B	D, R, Q, M or B	string
	Select a specific SEED quality indicator, handling is data center dependent.
minimumlength		optional	0.0	≥ zero	float
	Limit results to continuous data segments of a minimum length specified in seconds.
longestonly		optional	FALSE	TRUE or FALSE	boolean
	Limit results to the longest continuous segment per channel.
format		optional	miniseed	miniseed	string
	Specify format of result, the default value is miniseed. If this parameter is not specified the service must return miniSEED.
nodata		optional	204	204 or 404	string
	Select status code for "no data", either 204 (default) or 404.

Valid Station Codes

A valid station code is any of those station codes registered with the International Federation of Digital Seismograph Networks (FDSN) that uploades data to the IRIS DMC.
Wild cards are '*' for any string and '?' for any single character. The CQSRG IRIS DMC Seismogram Download web page does not allow for wildcards.

Valid Location Codes

The IRIS DMC web service uses a two character code to specify the data source (location) from which the data is derived.
Typical codes are '--', '00', and '10'; but there can be other combinations.
The CQSRG IRIS DMC Seismogram Download web page allows the selection of the '??' wildcard.

Valid Channel Codes

The IRIS DMC web service uses a three character code to specify the SEED channel(s) from which to get the data. Multiple channel codes are comma-separated.
The CQSRG IRIS DMC Seismogram Download web page only allows the selection of one channel code, but does allow that code to have '?' wildcards.

Requests to the IRIS DMC using the query method

A reference document describing the correct way to request seismograms from the IRIS DMC is available.

The seismograms are obtained from the IRIS DMC by sending an HTTP GET parameterised request to their web service.

The parameters are submitted as key=value pairs and may not be specified more than once; if a parameter is submitted multiple times the result is undefined.

The query string (name/value pairs) is sent in the URL of an HTTP GET request as in the following example (click on the link and wait for the reply - it may take up to a minute):

http://service.iris.edu/fdsnws/dataselect/1/query?network=AU&station=EIDS&starttime=2012-01-01T00:00:00&endtime=2012-01-01T12:00:00

If the requested information is available then it is returned to the caller as a MiniSEED file and the requester is offered the option of saving it to the local computer.

If the requested information is not available then the requester receives a message to advise so.

NOTE: Depending on the amount of data contained in the requested resource it may take several minutes to service the request.
For instance, a request for high resolution data from three seismograph channels may contain 15 MBytes and take up to 5 minutes to service.
Depending on the speed of your data link it may take even longer; so, you may need to be patient.