Beamforming is a Julia module for the array analysis of seismic data, using Seis.jl.
julia> ] # press ']' to enter pkg mode
(v1.7) pkg> add https://github.com/anowacki/Geodesics.jl https://github.com/anowacki/Seis.jl https://github.com/anowacki/Beamforming.jlBeamforming.jl requires Julia v1.6 or above.
The main functions exported are:
- For traditional beamforming:
array_response: Compute the array response function for a set of stationsbeamform: Compute the beam power across a grid of slowness points (as in f–k analysis)vespagram: Compute a slowness vespagram
- For cross-correlation beamforming:
crosscorrelation_array_responsecrosscorrelation_beamform
Docstrings are exhaustive, and can be consulted for usage of these
functions. To bring up docstrings in the REPL, type ? followed
by the name of the function and press return.
The array response for a set of stations can be computed like so:
using Beamforming, Seis
t = sample_data(:array); # 60 UK stations
# Array response parameters
arf = array_response(t,
5, # Maximum slowness in s/°
0.1, # Slowness grid spacing
0.1, # Minimum frequency in Hz
1, # Maximum frequency
0.1, # Frequency spacing
true # `true` for s/° slowness; `false` for s/km
)
plot(arf, powscale=:dB) # If Plots is installed
Beamforming can be performed like so:
bf = beamform(t,
1100, # Start time in s
1160, # End time in s
-1, # Minimum east slowness in s/°
0.5, # Maximum east slowness
0, # Minimum north slowness
4, # Maximum north slowness
0.01 # Slowness spacing
)
plot(bf, phases=["PKiKP", "PKIKP"])
Compute a vespagram like so:
vesp = vespagram(t,
1110, # Start time in s
1150, # End time
0, # Minimum slowness in s/°
4, # Maximum slowness
0.01, # Slowness spacing
)
plot(vesp, phases=["PKiKP", "PKIKP"], clim=(-1,1))
If you have installed Plots to your environment, then you can easily create plots as shown above.
For more help on plotting commands provided in this package, call up
the online help for Beamforming.plot:
help?> Beamforming.plotTo plot the predicted location in slowness and time of arrivals, you can install SeisTau.jl. (See the installation notes for more.)
Simply do using SeisTau, then the phases option to plot will
enable easy predicted phase arrival plotting for BeamformGrids
and VespaGrids, produced respectively by beamform and
vespagram.
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