README

pysep
SEP = seismogram extraction and processing

pysep uses obspy tools to request seismic data, process data, and write out sac files.
Our motivation is to have files prepared for moment tensor inversions.
However the sac files can be used for other purposes as well.

download:
git clone https://github.com/uafgeotools/pysep.git

What pysep does:
+ input event information or get it from IRIS. You can also loop over multiple events.
+ extract waveforms using get_waveforms_bulk
+ makes sure that the three-component waveforms for a station are of equal length
+ write sets of sac files with headers
+ plot station map
+ save station .xml file 

OPTIONAL STEPS
+ demean or detrend the waveforms
+ prefilter option (prior to removing instrument response)
    (a) none
    (b) based on window length and sample rate
    (c) input filter periods, checked according to window length and sample rate
+ filter extracted waveforms (causal, acausal, low-pass, etc)
+ remove instrument response
+ scale amplitude of the waveforms
+ resample
+ input taper fraction (useful for short time-windows)
+ add null traces so that there are always 3 components (required when rotating)
+ rotate to RTZ, taking the sensor orientation into consideration
+ rotate to UVW triaxial orthogonal frame of the T120PH Nanometrics sensor
  (useful for isolating spurious signals to sensor components)
+ debugging plots plots: spectrograms, instrument response

Additonal features
+ access embargoed data sets from IRIS (requires user name and password)
+ interface with LLNL database of nuclear explosion and earthquake waveforms (see below)

contributors (alphabetical):
Celso Alvizuri
Lion Krischer
Vipul Silwal
Kyle Smith
Cole Richards
Carl Tape
Liam Toney

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MAIN SCRIPTS:
run_getwaveform.py
event_input.py         -- source parameters for example events

MAIN FUNCTIONS:
getwaveform.py         -- to get data from IRIS/BK/LLNL databases

check_getwaveform.bash -- run example events and check the output files against pre-saved versions
                         
getwaveform_saved
   check_filenames     -- directory of list of files for example events in event_input.py

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pysep interfaces with the databases of:
W. Walter et al. (2006)
  An assembled western United States dataset for regional seismic analysis
  ISSO 9660 CD, LLNL release UCRL-MI-222502
The database can be downloaded from IRIS DMC at
  https://ds.iris.edu/mda/18-001
The package needed to access these waveforms is here:
   https://github.com/krischer/llnl_db_client
Follow the install instructions, then set a symbolic link as
   ln -s /PATH_TO_LLNL_CLIENT/llnl_db_client .

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