Global Positioning System Data, Southern California Earthquake Center

Global Positioning System data archived at the Southern California
Earthquake Center (SCEC) Data Center were collected due to the
collaborative efforts of the SCEC office, USGS, and other
organizations in order to provide comprehensive GPS measurements for
earthquake analysis. These data are available on-line through the SCEC
Data Center World Wide Web server at:

"http://www.scign.org/"

The data are archived in RINEX format and are available for the
following time periods and locations:

1991 San Bernardino County Survey
Post Landers Data (July 1 - July 25, 1992)
1994 SCEC GPS files - July 1 to present
1994 NGS GPS data

A full index of site locations is also available.

The following information about the GPS data sets was extracted from
the UCLA SCEC FTP site:

Archive Contents

The GPS data archive consists of four parts: The raw and RINEX
format GPS data, the site descriptions and log sheets that go
with these data, the indexes to the data and the sites, and
solution files from the processed data.

Data Archive Structure

GPS data that has been RINEXED and checked for major quality
problems is kept on-line at the SCEC data center. This disk is
/archive/gps. Below this the data is grouped first by year (e.g.
"94data") then by file type (RINEX), and then by day of year
(e.g. 017). With this structure it is possible to rapidly
construct the path from the one line entry for the data file in
the data index.

Archive Indexes

Two indexes are presently available, a site index (siteindx) and
a data index (dataindx). These are available from the SCEC data
center in the directory /archive/gps/indexes. There are
corresponding documentation files for these indexes. These files
are also available from the ftp site where two versions of
dataindx are available. dataindx.dc is an index to all of the
files available at the data center while dataindx.all is an index
to all of the data in the UCLA collection. With time the
dataindx.dc file will grow as data is transferred and will come
to look more like dataindx.all.