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NOTICE!!! THIS PROGRAM COMES WITH NO WARRANTY, TO THE EXTEND PERMITED BY LAW!

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ABC: AmBient noise and Coda

• To extract empirical green's funcions(EGFs) from seismic ambient noise or coda with seismic interferomatry method.
• Actually, it's to compute cross-correlation time functios of one station-pair.

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1️⃣ Here is given raw data with 86400 seconds long (one day) and sampling rate of 5 Hz.

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2️⃣ Cut coda from 10k - 40k seconds after event time.

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3️⃣ Execute band-pass filtering with period range of 15 - 50 seconds.

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4️⃣ Temporal normalization with run-absolute-mean method

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5️⃣ Spectral whitening with run-absolute-mean method

results in time domain

 -

results in frequency domain

• 

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6️⃣ Compute cross-correlation time function

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Denpendencies

• Linux or Mac OS platform;
• FFTW3 (Fast Foureier Transform in the West) ;

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Usage

abc_egf file.lst

• file.lst: sac1 sac2 year mon day hour min sec start0 cut_npts cor_name lag_time

parameter	meaning
sac1	SAC file1
sac2	SAC file2
year	year of seismic event happening
mon	month of seismic event happening
day	day of seismic event happening
hour	hour of seismic event happening
min	minute of seismic event happening
sec:	second of seismic event happening
start0	time of after seismic event happening
cut_npts	points number of cutting
cor_name	name of cross-correlation
lag_time	lag time of cross-correlation

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Contribution

• Author: Xuping Feng
• Email: geophydogvon@gmail.com

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Reference

Bensen, G. D., et al. "Processing seismic ambient noise data to obtain reliable broad-band surface wave dispersion measurements."  -
Geophysical Journal International 169.3 (2007): 1239-1260.