pysep.utils.cap_sac#

Utils to honor file formats from SAC and CAP

For SAC header names and descriptions, see:

http://www.adc1.iris.edu/files/sac-manual/manual/file_format.html

Module Contents#

Functions#

write_cap_weights_files(st[, path_out, order_by])

Write CAP (Cut-and-Paste) moment tensor inversion code weight files,

append_sac_headers(st, event, inv)

Wrapper for trace header appending to get a loop and some logic in

_append_sac_headers_trace(tr, event, inv)

Append SAC headers to ObsPy streams given event and station metadata.

format_sac_header_w_taup_traveltimes(st[, model, ...])

Add TauP travel times to the SAC headers using information in the SAC header

format_sac_headers_post_rotation(st)

SAC headers do not update when rotating so we need to apply manual

origin_time_from_sac_header(sac_header)

Build a UTCDateTime origin time from values in the SAC header appended to

Attributes#

SACDICT

pysep.utils.cap_sac.SACDICT[source]#
pysep.utils.cap_sac.write_cap_weights_files(st, path_out='./', order_by='dist')[source]#

Write CAP (Cut-and-Paste) moment tensor inversion code weight files, assuming that SAC headers are already present.

TODO re-add Ptime setting with event.picks

Replaces write_cap_weights

The weight file has columns corresponding to the following:

0: EVENT_STATION_ID 1: DIST_KM 2: BODY_Z 3: BODY_R 4: SURF_Z 5: SURF_R 6: SURF_T 7: P_ARRIVAL 8: LEGACY (unused) 9: S_ARRIVAL 10: LEGACY (unused) 11: STATIC CORRECTION RAYLEIGH

Parameters:

  • st (obspy.core.stream.Stream) – input stream to use to write CAP weight files, expected to have SAC header

  • path_out (str) – path to write the weight file, filenames are set by default inside the function

  • order_by (str) – how to order the list of stations that gets written out available options are: * dist: order by smallest to largest source-receiver distance (default) * az: order by smallest to largest azimuth (deg) * code: order alphabetically by station name

pysep.utils.cap_sac.append_sac_headers(st, event, inv)[source]#

Wrapper for trace header appending to get a loop and some logic in

Parameters:

  • st (obspy.core.stream.Stream) – Stream to append SAC header to

  • event (obspy.core.event.Event) – Event with metadata for SAC header

  • event – StationXML with metadata for SAC header

Return type:

obspy.core.stream.Stream

Returns:

Stream with SAC headers, those that could not be appended to have been removed from the stream

pysep.utils.cap_sac._append_sac_headers_trace(tr, event, inv)[source]#

Append SAC headers to ObsPy streams given event and station metadata. Also add ‘back_azimuth’ to Stream stats which can be used for rotation.

Rewritten from: util_write_cap.add_sac_metadata()

TODO Add back in information removed from original function

  • Add sensor type somewhere, previously stored in KT? (used for picks)

Note

We explicitely set ‘iztype, ‘b’ and ‘e’ in the SAC header to tell ObsPy that the trace start is NOT the origin time. Otherwise all the relative timing (e.g., picks) will be wrong.

Parameters:

  • tr (obspy.core.trace.Trace) – Trace to append SAC header to

  • event (obspy.core.event.Event) – Event with metadata for SAC header

  • event – StationXML with metadata for SAC header

Return type:

obspy.core.trace.Trace

Returns:

Trace with appended SAC header

pysep.utils.cap_sac.format_sac_header_w_taup_traveltimes(st, model='ak135', phase_list=('ttall',))[source]#

Add TauP travel times to the SAC headers using information in the SAC header Also get some information from TauP regarding incident angle, takeoff angle Hardcoded to only look at P and S arrivals (both upgoing and downgoing)

TODO Probably find better ways to store arrival time and incident angles

Note

This function expects that the Stream has been formatted with SAC header

Note

SAC header writing could probably be in a loop, but I think it’s more readable to see P and S values getting written separately.

Parameters:

  • st (obspy.core.stream.Stream) – Stream object with SAC headers which will be written to with new SAC header attributser

  • model (str) – name of the TauP model to use for arrival times etc. defaults to ‘ak135’

  • phase_list (list of str) – phase names to get ray information from TauP with. Defaults to ‘ttall’, which is ObsPy’s default for getting all phase arrivals. Must match Phases expected by TauP (see ObsPy TauP documentation for acceptable phases).

pysep.utils.cap_sac.format_sac_headers_post_rotation(st)[source]#

SAC headers do not update when rotating so we need to apply manual changes to the azimuth, inclination and naming values

TODO is this necessary? Who is using the SAC headers and what info

do they need? Or can we just re-run SAC header appending?

Parameters:

st (obspy.core.stream.Stream) – Stream to append SAC headers for

pysep.utils.cap_sac.origin_time_from_sac_header(sac_header)[source]#

Build a UTCDateTime origin time from values in the SAC header appended to an ObsPy trace.

Parameters:

sac_header (obspy.core.util.attribdict.AttribDict) – SAC header built by append_sac_header()

Return type:

UTCDateTime

Returns:

event origin time built from SAC header