Information about leveling systems in StationXML file

[WayneCrawford]

Dear Wayne,

I think that the information about leveling system may help researchers how sensors are tilted. During the analysis of tilt noise, I found that the tilt angles of sensor estimated by transfer function between Z-H is much larger than that reported by leveling unit's tilt meter (Kawano et al., 2023, BSSA) and the tile angle of the Z-component of CMG-3T is aligned to the tile of the leveling unit. This discrepancy could be recognized only when leveling unit information was described.

For example

leveling unit: ERI GLC-02, tolerance : 0.03 degree, accuracy : 0.01 degree

In case of Japanese BBOBS, tilt angles of two horizontal components of leveling unit are recorded once a day during an observation, so it is possible to describe the observed tilt angle. It is not so often but tilt angles could be changed during an observation, Describing the observed tilt in comments is not proper, I think. So, only tolerance and accuracy of the leveling system are included.

Cheers,

Takehi

[WayneCrawford]

I agree that the actual tilt angles don't belong in the StationXML. They could be put in a miniSEED channel (if the sampling rate is regular) or maybe in a State of Health file, although I don't know if/how these files are stored at data centers. There was a WP5 action on standardizing SOH files, but it didn't seem to get traction.

[WayneCrawford]

JSimon: Measured Tilt angles could be included in new "GEOCSV" format.

WCrawford: Should we add this to OBS-specific parameters (like clock drift and leapseconds) or try to get it added to the next version of StationXML?

Level = "Station"

Wayne should write to Chad Trabant to see if this could/should be added to next version of StationXML. If not, specify OBS-level description

[WayneCrawford]

Wayne created new issue #31 about OBS-specific elements, including leveling system.

Keeping this issue open because there is no issue yet about the level measurements in GeoCSV or SOH