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FDSN / OBS-standards

A repository for the discussion an development for Ocean Bottom Seismology standards
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Information about leveling systems in StationXML file #28

Open WayneCrawford opened 1 month ago

WayneCrawford commented 1 month ago

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 commented 1 month ago

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.