This data set comprises data collected by the University of Washington Geodetic and Seismic Sensor Module (GSSM) on the MARS cabled observatory from June 13, 2017 to December 14, 2019. The GSSM and this experiment are described in the paper Wilcock. W. S. D., D. A. Manalang, E. K. Fredrickson, M. J. Harrington, G. Cram, J. Tilley, J. Burnett, D. Martin, T. Kobayashi, J. M. Paros (2020), A thirty-month seafloor test of the A-0-A method for calibrating pressure gauges, Frontiers in Earth Sciences. All files are in a compressed tar file GSSM.tar of a directory GSSM. The tar file was created with the following command: tar czvf GSSM.tar GSSM ______________ The directory GSSM includes a subdirectory DOCUMENTS with the following files: DQ manual_8819-001.pdf - The Paroscientific Digiquartz manual that describes the acquisition boards that were used for acceleration, the two pressure sensors, and the barometer. Paros_Module_Certs.pdf - The certifications of accelerometer, two pressure sensors and the barometer and the factory supplied configuration settings of the acquisition boards. AccelerometerConfig.txt ? Printout of the configuration of the accelerometer acquisition board before and after a change in the filter settings on 8/25/2017. PressureConfig.txt ? Printout of the configuration of the pressure acquisition board before and after a change in the filter settings on 8/25/2017. Only one pressure gauge serial number is listed in the printout, but both were operated by this board. G8085_Configuring_A-0-A_System.pdf - Copy of a Paroscientific technical note on Configuring the A-0-A Seafloor Pressure Calibration System. G8096_Triaxial_Accelerometer.pdf ? Copy of a Paroscientific technical note on ?Triaxial Accelerometers for Improved Seismic and Geodetic Measurements?. ______________ The data is stored in daily netcdf files that are in daily subdirectories with names of the form ?yyyy-mm-dd? where ?yyyy? is the year, ?mm? is the month and ?dd? is the month (e.g., ?2017-07-04?). Each netcdf file also includes the date in a similar format: ________ Accelerometer NetCDF Data File Name: GSSM-Accel_yyyy-mm-dd.nc Variables: accelX ? the acceleration in the X direction (m/s). The X-channel is oriented up.* accelY ? the acceleration in the Y direction (m/s). The Y-channel is oriented at an azimuth of 330ø (clockwise relative to North)*. accelZ ? the acceleration in the Z direction (m/s). The Z-channel is oriented at an azimuth of 240ø (clockwise relative to North)*. temp ? temperature (øC) measured by the accelerometer. time - Unix Epoch Time in milliseconds (number of milliseconds since January 1 1970, 00:00:00 UTC ignoring leap seconds) at which the sample was acquired by the instrument. shoreTimestamp - Unix Epoch Time in milliseconds (number of milliseconds since January 1 1970, 00:00:00 UTC ignoring leap seconds) at which the sample was received at the shore station. This typically lags the sample acquisition time by only a few milliseconds**. rss ? total acceleration (m/s) obtained as the square root of sum of the squared channel outputs after adjustment with an internal alignment matrix provided by the manufacturer that corrects for small non-orthogonality of the 3 channels. longtitude ? Longitude in decimal degrees of the station. latitude ? Latitude in decimal degrees of the station. station ? Station number (set to 1 for this deployment). *Note that the conventions for the accelerometer channels directions are that accelerations are positive when they are in a direction that points away from the channel orientation. Thus, acceleration in the X direction are positive because they point away from up. **Note that inconsistencies between the time and shoreTimestamp variables can be used to identify timing errors that occasionally result from a spurious sample collected in the instrument as a result of a glitch in the pulse per second timing signal provided by the MARS observatory. The data has not been corrected to remove these spurious samples. ________ Barometer NetCDF Data File Name: GSSM-Barom_yyyy-mm-dd.nc Variables: pressure ? Pressure (Pa) measured by the barometer. temp ? temperature (øC) measured by the accelerometer. time ? as for the accelerometer data file. shoreTimestamp ? as for the accelerometer data file. longtitude ? as for the accelerometer data file. latitude ? as for the accelerometer data file. station ? as for the accelerometer data file. ________ Pressure NetCDF Data File Name: GSSM-Pres_yyyy-mm-dd.nc Variables: pressure1 ? Pressure (Pa) measured by the first pressure sensor (S/N 133958)***. temp1 ? temperature (øC) measured by the first pressure sensor. pressure2 ? Pressure (Pa) measured by the second pressure sensor (S/N 133960)***. temp2 ? temperature (øC) measured by the second pressure sensor. time ? as for the accelerometer data file. shoreTimestamp ? as for the accelerometer data file. longtitude ? as for the accelerometer data file. latitude ? as for the accelerometer data file. station ? as for the accelerometer data file. ***The pressure gauges record the external pressure except during 5 minute calibrations when the measure the internal atmospheric pressure of the pressure case. The onset of 154 calibrations (the first being an engineering test immediately upon the deployment and the remaining 153 being used to calibrate the sensor drift) occurred at the following times in UTC 13-Jun-2017 18:17:23 19-Jun-2017 19:57:04 20-Jun-2017 20:20:28 21-Jun-2017 21:59:01 22-Jun-2017 21:21:57 24-Jun-2017 00:12:31 26-Jun-2017 22:20:57 27-Jun-2017 20:32:54 28-Jun-2017 20:44:55 30-Jun-2017 00:12:54 30-Jun-2017 22:30:04 03-Jul-2017 20:45:04 05-Jul-2017 20:37:04 06-Jul-2017 20:52:05 07-Jul-2017 20:19:04 10-Jul-2017 21:30:04 11-Jul-2017 20:30:09 12-Jul-2017 21:14:04 13-Jul-2017 21:52:04 14-Jul-2017 23:07:05 17-Jul-2017 21:00:07 18-Jul-2017 21:00:07 19-Jul-2017 21:00:07 20-Jul-2017 21:00:07 21-Jul-2017 21:00:07 24-Jul-2017 21:00:07 25-Jul-2017 21:00:07 26-Jul-2017 21:00:07 27-Jul-2017 21:00:07 28-Jul-2017 21:00:07 31-Jul-2017 21:00:07 02-Aug-2017 21:00:07 04-Aug-2017 21:00:07 07-Aug-2017 21:00:07 09-Aug-2017 21:00:07 11-Aug-2017 21:00:07 14-Aug-2017 21:00:07 16-Aug-2017 21:00:07 18-Aug-2017 21:00:07 21-Aug-2017 21:00:07 23-Aug-2017 21:00:07 25-Aug-2017 21:00:05 28-Aug-2017 21:00:05 30-Aug-2017 21:00:06 01-Sep-2017 21:00:06 04-Sep-2017 21:00:06 06-Sep-2017 21:00:06 08-Sep-2017 21:00:06 11-Sep-2017 21:00:06 13-Sep-2017 21:00:06 15-Sep-2017 21:00:06 18-Sep-2017 21:00:06 21-Sep-2017 21:00:06 25-Sep-2017 21:00:07 28-Sep-2017 21:00:07 02-Oct-2017 21:00:07 05-Oct-2017 21:00:07 09-Oct-2017 21:00:07 12-Oct-2017 21:00:07 16-Oct-2017 21:00:07 19-Oct-2017 21:00:07 23-Oct-2017 21:00:07 26-Oct-2017 21:00:07 30-Oct-2017 21:00:07 02-Nov-2017 21:00:07 06-Nov-2017 21:00:07 09-Nov-2017 21:00:07 13-Nov-2017 21:00:07 16-Nov-2017 21:00:06 20-Nov-2017 21:00:06 23-Nov-2017 21:00:07 27-Nov-2017 21:00:07 30-Nov-2017 21:00:07 04-Dec-2017 21:00:06 07-Dec-2017 21:00:06 11-Dec-2017 21:00:07 14-Dec-2017 21:00:07 18-Dec-2017 21:00:07 25-Dec-2017 21:00:07 01-Jan-2018 21:00:07 08-Jan-2018 21:00:07 15-Jan-2018 21:00:07 29-Jan-2018 21:00:06 05-Feb-2018 21:00:07 12-Feb-2018 21:00:07 19-Feb-2018 21:00:07 26-Feb-2018 21:00:07 05-Mar-2018 21:00:07 20-Mar-2018 21:00:06 27-Mar-2018 21:00:06 03-Apr-2018 21:00:05 10-Apr-2018 21:00:05 17-Apr-2018 21:00:06 24-Apr-2018 21:00:06 01-May-2018 21:00:05 08-May-2018 21:00:05 15-May-2018 21:00:06 22-May-2018 21:00:06 29-May-2018 21:00:05 05-Jun-2018 21:00:06 12-Jun-2018 21:00:05 01-Jul-2018 21:00:06 15-Jul-2018 21:00:06 01-Aug-2018 21:00:06 15-Aug-2018 21:00:07 01-Sep-2018 21:00:06 15-Sep-2018 21:00:06 01-Oct-2018 21:00:06 15-Oct-2018 21:00:13 01-Nov-2018 21:00:14 01-Dec-2018 21:00:05 15-Dec-2018 21:00:07 01-Jan-2019 21:00:10 15-Jan-2019 21:00:13 01-Feb-2019 21:00:19 15-Feb-2019 21:00:18 01-Mar-2019 21:00:18 15-Mar-2019 21:00:18 01-Apr-2019 21:00:20 15-Apr-2019 21:00:19 01-May-2019 21:00:20 15-May-2019 21:00:20 01-Jun-2019 21:00:19 15-Jun-2019 21:00:20 05-Jul-2019 21:00:12 06-Jul-2019 21:00:12 07-Jul-2019 21:00:12 08-Jul-2019 21:00:12 09-Jul-2019 21:00:12 10-Jul-2019 21:00:12 11-Jul-2019 21:00:12 12-Jul-2019 21:00:12 13-Jul-2019 21:00:12 14-Jul-2019 21:00:12 15-Jul-2019 21:00:11 22-Jul-2019 21:00:13 29-Jul-2019 21:00:14 05-Aug-2019 21:00:18 12-Aug-2019 21:00:19 19-Aug-2019 21:00:19 26-Aug-2019 21:00:18 02-Sep-2019 21:00:18 09-Sep-2019 21:00:18 16-Sep-2019 21:00:19 23-Sep-2019 21:00:20 30-Sep-2019 21:00:11 07-Oct-2019 21:00:12 14-Oct-2019 21:00:11 21-Oct-2019 21:00:12 28-Oct-2019 21:00:16 11-Nov-2019 21:00:15 18-Nov-2019 21:00:16 25-Nov-2019 21:00:15 02-Dec-2019 21:00:16