SKS splitting offline¶
Program sks_offline.py
¶
Calculates single station SKS splitting results from data previously downloaded using the program SKS data preparation. Station selection is specified by a network and station code. The data base is provided in a pickled file as a StDb dictionary.
Usage¶
$ sks_offline.py -h
Usage: sks_offline.py [options] <station database>
Script to process and calculate the spliting parmaters for a dataset that has
already been downloaded by sks_prep.py.
Options:
-h, --help show this help message and exit
--keys=STKEYS Specify a comma separated list of station keys for
which to perform analysis. These must be contained
within the station database. Partial keys will be used
to match against those in the dictionary. For
instance, providing IU will match with all stations in
the IU network [Default processes all stations in the
database]
Event Settings:
Settings associated with refining the events to include in matching
station pairs
--start-time=STARTT
Specify a UTCDateTime compatible string representing
the start time for the event search. This will
override any station start times. [Default more recent
start date for each station pair]
--end-time=ENDT Specify a UTCDateTime compatible string representing
the start time for the event search. This will
override any station end times [Default older end date
for each the pair of stations]
-R, --reverse-order
Reverse order of events. Default behaviour starts at
oldest event and works towards most recent. Specify
reverse order and instead the program will start with
the most recent events and work towards older
--min-mag=MINMAG Specify the minimum magnitude of event for which to
search. [Default 6.0]
--max-mag=MAXMAG Specify the maximum magnitude of event for which to
search. [Default None, ie no limit]
Geometry Settings:
Settings associatd with the event-station geometries
--min-dist=MINDIST Specify the minimum great circle distance (degrees)
between the station and event. [Default 85]
--max-dist=MAXDIST Specify the maximum great circle distance (degrees)
between the station and event. [Default 120]
Parameter Settings:
Miscellaneous default values and settings
--Vp=VP Specify default P velocity value. [Default 6.0 km/s]
--SNR=MSNR Specify the SNR threshold used to determine whether
events are processedc. [Default 7.5]
--window=DTS Specify time window length before and after the SKS
arrival. The total window length is 2*dst. [Default
120 s]
--max-delay=MAXDT Specify the maximum delay time. [Default 4 s]
--time-increment=DDT
Specify the time increment. [Default 0.1 s]
--angle-increment=DPHI
Specify the angle increment. [Default 1 d]
--transverse-SNR=SNRTLIM
Specify the minimum SNR Threshold for the Transverse
component to be considered Non-Null. [Default 1.]
Example¶
Assume we have followed the steps in SKS data preparation and saved some data to disk
in a folder called DATA_D85-120_M6.0+_S7.5+
. Now we can simply run
sks_offline.py
by specifying the data folder containing the prepared
waveforms, which execute the SKS splitting analysis and generate
Figures and picking windows similar to SKS splitting on the fly (see the program
for details).
$ sks_offline.py ./DATA_D85-120_M6.0+_S7.5+
|===============================================|
|===============================================|
| TA.EPYK |
|===============================================|
|===============================================|
| Working on 13 saved events |
|===============================================|
****************************************************
* #1 (2/13): 20130409_115250
* Origin Time: 2013-04-09 11:52:50
* Lat: 28.45; Lon: 51.63
* Dep: 12.80; Mag: 6.3
* EPYK -> Ev: 9467.98 km; 85.15 deg; 352.65; 3.35
* SNR Passed: 20.13 >= 7.5
* --> Calculating Rotation-Correlation (RC) Splitting
* --> Calculating Silver-Chan (SC) Splitting
...
This uses all default settings for window lengths, magnitude criteria, etc. See the program SKS splitting on the fly for details on the interactions with the code to produce splitting results.