"""
Part of the EQcorrscan package: tools to convert SAC headers to obspy event \
objects.
.. note:: This functionality is not supported for obspy versions below \
1.0.0 as references times are not read in by SACIO, which are needed \
for defining pick times.
:copyright:
EQcorrscan developers.
:license:
GNU Lesser General Public License, Version 3
(https://www.gnu.org/copyleft/lesser.html)
"""
import logging
import obspy
from obspy import Stream, UTCDateTime
from obspy.core.event import Event, Origin, WaveformStreamID, Pick
PICK_KEYS = ['t0', 't1', 't2', 't3', 't4', 't5', 't6', 't7', 't8', 't9', 'a']
PHASE_KEYS = ["k{0}".format(pk) for pk in PICK_KEYS]
Logger = logging.getLogger(__name__)
def _version_check():
if int(obspy.__version__.split('.')[0]) < 1:
msg = 'Obspy version: ' + obspy.__version__ + ' does not have ' +\
'correct reference time handling, please upgrade to ' +\
'version > 1.0.0'
raise NotImplementedError(msg)
[docs]
def sactoevent(st):
"""
Convert SAC headers (picks only) to obspy event class.
Picks are taken from header values a, t[0-9]. A phase-hint in the
corresponding kt[0-9] slot is recommended.
:type st: obspy.core.stream.Stream
:param st: Stream of waveforms including SAC headers.
:returns: Event with picks taken from SAC headers.
:rtype: :class:`obspy.core.event.event.Event`
.. note::
This functionality is not supported for obspy versions below 1.0.0 as
reference times are not read in by SACIO, which are needed for defining
pick times.
.. note::
Takes the event origin information from the first trace in the
stream - to ensure this works as you expect, please populate the
evla, evlo, evdp and nzyear, nzjday, nzhour, nzmin, nzsec, nzmsec
for all traces with the same values.
>>> from obspy import read
>>> # Get the path to the test data
>>> import eqcorrscan
>>> import os
>>> TEST_PATH = os.path.dirname(eqcorrscan.__file__) + '/tests/test_data'
>>> st = read(TEST_PATH + '/SAC/2014p611252/*')
>>> event = sactoevent(st)
>>> print(event.origins[0].time)
2014-08-15T03:55:21.057000Z
>>> print(event.picks[0].phase_hint)
S
"""
# Check the version
_version_check()
# Set the default SAC nan values
float_nan = -12345.0
if not isinstance(st, Stream):
msg = ('st must be a stream object, if you have just read in ' +
'multiple SAC files you may have a list of streams, convert ' +
'using: st = Stream([tr[0] for tr in st])')
raise ValueError(msg)
# Note, don't do this internally as we need to ensure that we are not
# taking traces from other events, the user should check this.
for tr in st:
if not tr.stats._format == 'SAC':
msg = ('%s.%s is not SAC formatted.' % (tr.stats.station,
tr.stats.channel))
raise ValueError(msg)
# Now we need to create an event!
event = Event()
event.origins.append(Origin())
# print(st[0].stats.sac.keys())
event.origins[0].time = UTCDateTime(
year=st[0].stats.sac.nzyear, julday=st[0].stats.sac.nzjday,
hour=st[0].stats.sac.nzhour, minute=st[0].stats.sac.nzmin,
second=st[0].stats.sac.nzsec,
microsecond=st[0].stats.sac.nzmsec * 1000)
try:
event.origins[0].latitude = st[0].stats.sac.evla
event.origins[0].longitude = st[0].stats.sac.evlo
event.origins[0].depth = st[0].stats.sac.evdp
# Catch filled with 12345.0 as nan
if event.origins[0].latitude == float_nan:
event.origins[0].latitude = None
if event.origins[0].longitude == float_nan:
event.origins[0].longitude = None
if event.origins[0].depth == float_nan:
event.origins[0].depth = None
except KeyError:
event.origins[0].latitude = None
event.origins[0].longitude = None
event.origins[0].depth = None
except AttributeError:
event.origins[0].latitude = None
event.origins[0].longitude = None
event.origins[0].depth = None
# Add in the picks
for tr in st:
reference_time = UTCDateTime(
year=tr.stats.sac.nzyear, julday=tr.stats.sac.nzjday,
hour=tr.stats.sac.nzhour, minute=tr.stats.sac.nzmin,
second=tr.stats.sac.nzsec,
microsecond=tr.stats.sac.nzmsec * 1000)
# Possible pick locations are in the t[0-9] slot
for pick_key, phase_key in zip(PICK_KEYS, PHASE_KEYS):
try:
if tr.stats.sac[pick_key] == float_nan:
# in version 0.10.2 and before. rather than not include
# the keys, the variables are filled with SAC nans.
Logger.debug(
'No pick in position {0} for trace {1}'.format(
pick_key, tr.id))
continue
pick_time = reference_time + tr.stats.sac[pick_key]
if phase_key in tr.stats.sac.keys():
phase_hint = tr.stats.sac[phase_key].split()[0]
else:
Logger.warning(
"No phase hint found for pick in {0}".format(pick_key))
phase_hint = None
except KeyError:
Logger.debug('No pick in position {0} for trace {1}'.format(
pick_key, tr.id))
continue
Logger.info(
'Found pick in position {0} for {1}'.format(pick_key, tr.id))
waveform_id = WaveformStreamID(station_code=tr.stats.station,
network_code=tr.stats.network,
channel_code=tr.stats.channel)
pick = Pick(waveform_id=waveform_id,
phase_hint=phase_hint,
time=pick_time)
event.picks.append(pick)
return event
if __name__ == '__main__':
import doctest
doctest.testmod()