These downloadable files from the GVS (Glendale-Verdugo Strain) instrument are 5-minute data, stored as ASCII files, compressed with bzip2. The data are in datalogger counts (read across and down), after a header which looks like (for example)
GVS LSM HDR 2002 242 2 20 0 2003 149 23 55 0 78596. STRN A01 300. .0 .0 1 0 0 .00 Strain measured along azimuth 14.71 deg E of N between 34.17837N 118.22011W and 34.17349N 118.22164W (558.8 M, sloping 2.3 deg). LSM HDR and RCLP are measured change in length, 0.1416 nanostrain per count, extension positive. RCLP is low- pass filtered (500 s RC filter). N LOA and S LOA are displacements of the N and S end points, also 0.1416 equivalent strain per count, unfiltered. Corrected strain is HDR - (NLOA+SLOA). VAC is about -3.1 nanobar/count. NOTE that the N and (especially) S LOA are subject to miscounting and should be checked against the secondary counters (STRN B). THESE DATA ARE RAW DATA AS RECORDED AND SHOULD BE INTERPRETED WITH CARE, AND WITH UNDERSTANDING OF THE PRINCIPLES OF THE INSTRUMENT
which means that the data consists of 78596 terms, with a sample interval of 300 seconds, from 2002:242:2:20:0 (UTC) through 2003:149:23:55:0. The channel name is LSM HDR, with the gain described in the accompanying notes.
The files currently available are: (1) strain, (2) a filtered version of the strain, (3) the North anchor, (4) the South anchor, (5) another version of the North anchor (as a check on the counting electronics) (6) another version of the South anchor (also as a check on the counting electronics, which for reasons still being investigated tend to miscount during daylight hours) (7) the vacuum (note that this may be saturated at times) (8) and the current used to stabilize the laser (diagnostic).