/Beamforming_in_frequency_domain

Coherent Signal Detection with Cross-Spectral Beamforming.

Primary LanguageC

F-K cross-spectral beamforming

Searching the back-azimuth and corresponding apparent slowness (or ray parameter)    
with F-K cross-spectral beamforming array method.

Installation

Go into the directory src and type make to compile and the executable command cross_spec_beam will be generated in the upper-level directory bin.

Dependencies

gcc or icc compiler; fftw3 for doing FFT; python3 for visualization.

Seismic data tested

Several data sets are prepared in folder "Data".

1 DATA1

Synthetic vertical-component seismograms with YASEIS (Ma, 2013)
    based on the PREM.
The source mechanism is explosion at depth of 20 km and the
    average distance is about 20 degress.

2 DATA2

Synthetic vertical-component seismograms with YASEIS (Ma, 2013)
    based on the PREM.
The source mechanism is explosion at depth of 20 km and the
    average distance is about 50 degress.

3 DATA3

Synthetic vertical-component seismograms with CPS (Herrmann, 2013)
    based on a multi-layered model.
The source mechanism is explosion at depth of 36 km and the
    average distance is about 500 km.

4 DATA4

Real vertical-component seismograms of NO network from NORSAR data
    center in Norway.
The major array (NORES) is composed of 7 sub-arrays.

5 DATA5

Real vertical-component seismograms of NO network from NORSAR data
    center in Norway.
The circle-shaped array is named ARCES and composed of 25 stations.

6 DATA_EVENT

Earthquake event data: 2017-06-22T12:31:04|13.7527|-90.9488|46.82|at,pt,us|NEIC PDE|us|pt17173000,at00ory83s,us20009p1a|mww|6.8|us|NEAR COAST OF GUATEMALA

Usage tips

input file preparation

The contents of input file are described by the following lines.

listfile1 #File of SAC list names;
200. #Lower limit of time in second;
400. #Upper limit of time in second;
0.25 #Lower limit of frequency of plane wave;
0.26 #Upper limit of frequency of plane wave;
0.01 #Lower limit of slowness in s/km;
0.15 #Upper limit of slowness in s/km;
0. #Lower limit of back-azimuth in degree;
360. #Upper limit of back-azimuth in degree;
81 #Segments of slowness;
181 #Segments of bazk-azimuth;
lonlat #Coordinate system: "lonlat", "km" or "meter";
out.txt #File of results.

steps

list SAC format files in a file, here listfile1; set parameters in input file, here input.para1; run an example with
../bin/cross_spec_beam input.para1
plot the spectra with
python plot_spectra.py input.para1 deg.

An example: back-azimuth and ray parameter of P or pP phase

2017-06-22T12:31:04|13.7527|-90.9488|46.82|at,pt,us|NEIC PDE|us|pt17173000,at00ory83s,us20009p1a|mww|6.8|us|NEAR COAST OF GUATEMALA

waveforms

wave

beamfoming power

../bin/cross_spec_beam input.para9
python plot_spectra.py input.para9 deg
beam

Feedback

geophydogvon@gmail.com