SYNOPSIS

PERL PROGRAM NAME:

AUTHOR: Juan Lorenzo (Perl module only)

DATE:

DESCRIPTION:

Version:

USE

NOTES

Examples

SYNOPSIS

SEISMIC UNIX NOTES SUPWS - Phase stack or phase-weighted stack (PWS) of adjacent traces

	 having the same key header word				



 supws <stdin >stdout [optional parameters]				



 Required parameters:							

	none								



 Optional parameters:						 	

	key=cdp	   key header word to stack on				

	pwr=1.0	   raise phase stack to power pwr			

	dt=(from header)  time sampling intervall in seconds		

	sl=0.0		window length in seconds used for smoothing	

			of the phase stack (weights)			

	ps=0		0 = output is PWS, 1 = output is phase stack	

	verbose=0	 1 = echo additional information		



 Note:								 	

	Phase weighted stacking is a tool for efficient incoherent noise

	reduction. An amplitude-unbiased coherency measure is designed	

	based on the instantaneous phase, which is used to weight the	

	samples of an ordinary, linear stack. The result is called the	

	phase-weighted stack (PWS) and is cleaned from incoherent noise.

	PWS thus permits detection of weak but coherent arrivals.	



	The phase-stack (coherency measure) has values between 0 and 1.	



	If the stacking is over cdp and the PWS option is set, then the	

	offset header field is set to zero. Otherwise, output traces get

	their headers from the first trace of each data ensemble to stack,

	including the offset field. Use "sushw" afterwards, if this is

	not acceptable.							







 Author: Nils Maercklin,

	 GeoForschungsZentrum (GFZ) Potsdam, Germany, 2001.

	 E-mail: nils@gfz-potsdam.de



 References:

	B. L. N. Kennett, 2000: Stacking three-component seismograms.

	 Geophysical Journal International, vol. 141, p. 263-269.

	M. Schimmel and H. Paulssen, 1997: Noise reduction and detection

	 of weak , coherent signals through phase-weighted stacks.

	 Geophysical Journal International, vol. 130, p. 497-505.

	M. T. Taner, A. F. Koehler, and R. E. Sheriff, 1979: Complex

	 seismic trace analysis. Geophysics, vol. 44, p. 1041-1063.



 Trace header fields accessed: ns

 Trace header fields modified: nhs, offset

User's notes (Juan Lorenzo) untested

CHANGES and their DATES

Import packages

instantiation of packages

Encapsulated hash of private variables

sub Step

collects switches and assembles bash instructions by adding the program name

sub note

collects switches and assembles bash instructions by adding the program name

sub clear

sub dt

sub key

sub ps

sub pwr

sub sl

sub verbose

sub get_max_index

max index = number of input variables -1