DMS Products: PDF-PSD PDF/PSD Bulk Data Delivery System

Summary

PDF/PSD Bulk Data Delivery System is an automated system that accepts BREQ_FAST-formatted requests and provides users with the requested PSD data files (daily bin files).

Description


Sample PDF analysis

Information on long-term noise levels at seismic stations is important for characterizing the current and past performance of seismic stations and detecting potential operational and/or instrumental station problems. Starting in 2004, data received by the IRIS DMC’s near-real time data collection systems (BUD and USArray) have been analyzed by its automated Quality Analysis Control Kit (QUACK) system. For its noise analysis, QUACK utilizes a version of the McNamara and Boaz software to gather noise information on every broadband station that transmits its data to the DMC in real time.

In their noise processing scheme, McNamara and Boaz calculate Power Spectral Density (PSD) for each 1-hour time series segment. Then the raw frequency distributions are constructed by gathering individual PSDs into frequency distribution bins. A histogram of PSD bins results in PDF (Power Density Function) plots in which transient noises map into a low-level background probability while ambient noise conditions appear as high probability occurrences. The web-based interface of QUACK enables users to customize and display PDFs for time interval of their choosing.

Access to the Power Spectral Density data

For those users interested in the raw PSD data (bin) files, IRIS DMC has implemented an automated system that accepts BREQ_FAST requests and provides user with the corresponding PSD data files (daily bin files). To obtain the PSD data files from this DMC service, users should email their BREQ_FAST requests to: pdfpsd@iris.washington.edu.

The following fields must be included in the BREQ_FAST request:

.NAME
.EMAIL
.LABEL
.END
request 1ine-1

request line-999

Example:

.NAME dmc
.EMAIL user@mayemail.com
.LABEL my_request
.END
LYUB TW 2010 11 08 22 49 46.0000 2010 11 08 23 13 46.0000 1 BH?  
KAKA AU 2010 11 08 22 53 28.0000 2010 11 08 23 17 28.0000 1 BH?  
LDF CI 2010 11 08 22 57 29.0000 2010 11 08 23 21 29.0000 1 BH?   
BTDF MS 2010 11 08 22 49 50.0000 2010 11 08 23 13 50.0000 1 BH?  

In response, the PSD Bulk Data Delivery system will bundle the selected PSD files into a gzipped tar file and notifies the user via email of their availability for download.

The structure of the delivered bundle is as follows:

Directory Structure

PDFPSD/network.station.location/channel/Yyyyy/Djjj.bin

where

PDFPSF - is the root directory of the PSD data files
network - is the network code
station - is the station code
location - is the location ID 
yyyy - is the year of the data file 
jjj - is the julian day of the data file

Djjj.bin File Format

Djjj.bin is a cumulative “bin” file containing the hour long PSD measurements for an entire day, where jjj is the julian day for any given file. The file type is ASCII with data presented in 3 columns. A MATLAB script is available (download) to plot PSDFs from these PSDs.

 FREQUENCY POWER #HITS 
 FREQUENCY POWER #HITS 
 FREQUENCY POWER #HITS 
 FREQUENCY POWER #HITS 
 FREQUENCY POWER #HITS 
 .
 .
 .
 .

where:

  • FREQUENCY is the frequency in Hertz
  • POWER is the power bin in (dB)
  • #HITS is the number of times

Citation

  • Trabant, C., A. R. Hutko, M. Bahavar, R. Karstens, T. Ahern and R. Aster (2012), Data products at the IRIS DMC: stepping-stones for research and other application, Seismological Research Letters, 83(6), 846:854. doi: 10.1785/0220120032

Credits

Timeline

2012-06-16
Released

DOI

There is no DOI currently assigned for this product.

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