[obspy-users] Obspy 1.0.0 sac header issues
cja12 at psu.edu
Wed Mar 23 12:47:45 CET 2016
I am finally getting around (being forced) to change a set of scripts to
adjust to the latest updates to obspy and came across a number of
The first issue has been discussed in February 2016, and is related to
setting sac-header location fields (stla, stlo, evla, evlo). Initially,
all these items have values of -12345 (this is a SAC default for unset
header values). When I set one of the items, say stlo, it appears that
obspy tries to compute the distance and azimuth using the existing
-12345 values, which throws an exception from the distance-azimuth
calculation ('out of bounds', because -12345 is not in the geographic
range). Unless you are handling/suppressing the exception, it can toss
you out of the current section of your code.
To work around that problem/feature, set lcalda = False, set the
location fields and then set lcalda = True. I am not sure rushing off to
compute the distance and azimuth is the right thing to do in a header
access implementation unless none of the key lats and lons equal -12345.
This could be checked in the code if you want to keep the current
approach. Or, am I missing something?
Also, I am perplexed by why i cannot store a value in the 'evdp' header
field. The documentation states that this is "not used", but it is an
essential piece of the header. From the documentation:
"Event depth below surface (meters). [not currently used]"
If I don't store an earthquake depth in 'evdp' where is depth
information supposed to be stored? What am I missing here?
Charles J. Ammon, Department of Geosciences
Penn State University / 440 Deike Bldg / University Park, PA 16802
VOICE: (814) 865 2310 / FAXES: (814) 863 7823 or (814) 863 8724
-------------- next part --------------
An HTML attachment was scrubbed...
More information about the obspy-users