[SAC-HELP] units of EVDP in SAC

[Arthur Snoke]

To my knowledge, since IRIS/SAC v100, EVDP (focal depth in the SAC 
header) has not been used in any SAC command.  Please let me know if there 
are commands I have overlooked.

Because of historical reasons, EVDP (focal depth) in SAC has the units 
according to the SAC manual.  RDSEED converts EVDP from kilometers (which 
it is in blockette 71 in SEED) to meters when writing SAC waveforms.

For v101.5, the units of EVDP will be of interest because we will (re) 
introduce a version of the TRAVELTIME command, in which for waveforms with 
a defined location and origin time one can calculate arrival times for 
body-wave phases using the iaspei-tau tables for either ak135 or iasp91 
velocity models.  For this command, the units of EVDP matter.

I personally would like to evolve towards having kilometers being the 
default unit for EVDP.  As a first step, kilometers would be the default 
choice for EVDP in TRAVELTIME.

The point of this note is a canvass of the community to find if there are 
any problems with using KM rather than M for EVDP.  Let me know if there 
are other programs that read SAC files and use EVDP assuming it is in 
meters.

Arthur