IRIS DMC Data Access Tutorial
|
||||||||
|
||||||||
|
|
The purpose of this document is to introduce users to the types of data archived at the IRIS DMC and how to request it. | |||||||
| Types of Data at the DMC | ||||||||
| Before making a data request, it is important to understand what types of data we have at the IRIS Data Management Center (DMC). There are basically two types of data (i.e. waveform data) - continuous and event-related - but multiple data products available for each type. Below are explanations of the different types of data available from the DMC. |
||||||||
| Continuous Data For users interested in time windowing their own data |
||||||||
|
BUD: near real-time, not quality
controlled (unQC'd), partial data sets |
|||||||
| Event Oriented Data For data users interested in predefined event-oriented time windows |
||||||||
|
SPYDER® data: near real-time,
unQC'd, partial data sets |
|||||||
| Assembled Data | ||||||||
|
The DMC distributes several pre-assembled data sets in non-SEED format and from diverse programs. A data set is considered "assembled" if it is in a format other than SEED (except for FARM data) and is therefore not accessible using our standard SEED data request methods. Assembled data sets, for the most part, come "as-is." Some sets can be broken up into smaller sets but most come as a complete package. Sources of assembled data sets include:
|
|||||||
| Data Request Tools | ||||||||
|
Assembled
Data Web Form
BUD
Interface
JWEED
NetDC
Restricted
Data
SeismiQuery
VASE
WebRequest
WILBER
II |
|||||||
| Receiving the Data | ||||||||
| SEED Data | ||||||||
|
All customized data requests (i.e. continuous data from the archive) and some BUD and WILBER II requests will result in the user receiving a SEED data volume either on tape or via anonymous FTP. A SEED volume consists of a control header section, describing the seismic stations and instrumentation, and a waveform data section. These two parts of a SEED volume can live separately as a dataless SEED file (just the headers) and a miniSEED file (just the data). Dataless SEED volumes can be downloaded (by network) via ftp from
ftp://ftp.iris.washington.edu/pub/RESPONSES/DATALESS_SEEDS/
or by sending a BREQ_FAST request to
JEvalResp
[a DHI client]
JPlotResp
[a DHI client] |
|||||||
| SEG-Y Data | ||||||||
| If your request results in a volume of data in SEG-Y format, you may need to refer to the Digital Tape Standards manual for details on your data set. We cannot provide you with this manual but you can purchase one from:
Some PASSCAL data sets are not in "true" SEG-Y format; they do not include complete reel identification headers and instead just have SEG-Y traces. This can cause problems if you try to view these files with some commercial analysis packages. The PASSCAL Software release includes tools that read, plot and gather PASSCAL SEG-Y data. For information about these tools, look here: http://www.passcal.nmt.edu/ |
||||||||
| Other data formats | ||||||||
| Some of our older data sets are not in SEED or SEG-Y. They may be UNIX tar files of traces in SAC, AH, or other formats. (Also, WILBER II offers SAC as an output option.) At times these tar files are compressed using standard UNIX compress. The name of these files generally reflects the data format in the suffix (example: filename.AH.tar.Z). |
||||||||
|
If you have any questions, please contact us: E-mail:
| ||||||||


