PDS_VERSION_ID     = PDS3
RECORD_TYPE        = STREAM
OBJECT             = TEXT
  PUBLICATION_DATE = 2016-05-16
  NOTE             = "VPDS_ARCHIVE_STRUCTURE document
                      in the Viking Lander 2 seismology experiment archive."
END_OBJECT         = TEXT
END

PDS Viking Seismometer Archive Structure				Ralph Lorenz   3/18/2016

The original raw 'VUSA' files retained by Y. Nakamura at University of Texas
were a heterogeneous concatenation of records in both Event and High rate modes
of the Viking seismometer instrument (see Anderson et al., JGR, 1977).  As such,
these files (with variable record length) were awkward to parse.  For PDS
archival these data are reformatted separately as VPDS files. A summary file
'WIND' for each mode provides high-level statistics of each record  (allowing
rapid and/or automated search for high-activity events, for example) together
with interpolated meteorological data to permit easy correlation of ambient
conditions with the seismometer readings. The raw data are  provided in a set of
files (X,Y,Z Amplitude and X,Y,Z Frequency for EVENT mode data, and X, Y, Z raw
readings for HIGH mode data) with an index number that allows simple cross-
reference to the summary files. The mapping is summarized below.


Summary file				                       Raw file
------------                               --------
Each record (line) gives statistics of 	   Each record (line) is the full raw
data in all 3 axes, plus interpolated	     record in one axis
meteorological quantities for 
correlation

VPDS_EVENT_WIND.TXT------------------
                                           VPDS_EVENT_XAmp.TXT
                                           VPDS_EVENT_YAmp.TXT
                                           VPDS_EVENT_ZAmp.TXT 
                                           VPDS_EVENT_XFreq.TXT
                                           VPDS_EVENT_YFreq.TXT
                                           VPDS_EVENT_ZFreq.TXT
VPDS_HIGH_WIND.TXT------------------
                                           VPDS_HIGH_XDAT.TXT
                                           VPDS_HIGH_YDAT.TXT
                                           VPDS_HIGH_ZDAT.TXT