The downloadable files from the PFO (Piñon Flat Observatory) instruments 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)
PFO NW HDR 2005 140 0 0 0 2005 288 23 55 0 42912. STRN E01
300. 0.0 0.0 2 0 0 0.00
Strain measured along azimuth 135.3 deg E of N between 33.61220N 116.45957W and
33.60752N -116.45403W (730.4 m, sloping -0.5 deg). NW LSM and NW HDR are length
change, 0.01354 nanostrain per count (ne/c) (LSM), 0.00677 ne/c (HDR). LSM is
filtered (500 s RC), extension -; HDR extension +. NW & SE LOA are displacements
of NW&SE piers measured with optical anchor, 0.00677 ne/c equivalent.
SE and NW W VAC are vacuum gauges, disgnostic only, 0.03 Pa/coount.
Approximately-corrected strain (in LSM counts) is LSM - (NW LOA + SE LOA)
THESE ARE RAW DATA AS RECORDED. USE THEM WITH CAUTION.
which means that the data consists of 42912 terms, with a sample interval of 300 seconds, from 2005:140:00:00:00 (UTC) through 2005:288:23:55:00. The channel name is NW HDR, with the gain described in the accompanying notes.
The files currently available are: (1) the NS strain, (2) a filtered version of the NS strain, (3) the north pier tilt, (4) the south fiber optical anchor, (5) another version of the sorth anchor (different optical fibers), (6) the vacuum at the north end; (7) the EW strain, (8) a filtered version of the EW strain, (9) the west optical anchor, (10) the east optical anchor, (11) the vacuum at the west end; (12) the NW-SE strain, (13) a filtered version of the NW-SE strain, (14) the northwest optical anchor, (15) the southeast optical anchor, (16) the vacuum at the northwest end; (17) the vacuum at the southeast end; (18) the tilt of the NW optics table; (19) the air temperature, (20) the ground temperature at 0.5 m depth, (21) the ground temperature at 1 m depth, (22) the ground temperature at 0.5 m depth in another location, (23) the air pressure (microbarograph), (24) the air pressure (barometer), (25) the solar radiation, (26) the cumulative rainfall, (27) the relative humidity, (28) the wind direction, and (29) the wind speed.