suinvvxzco.su.main

su 的源代码库

 SUINVXZCO - Seismic INVersion of Common Offset data for a smooth 	
             velocity function V(X,Z) plus a slowness perturbation vp(x,z)

     suinvvxzco <infile >outfile [optional parameters] 		

 Required Parameters:							
 vfile                  file containing velocity array v[nx][nz]	
 nx=                    number of x samples (2nd dimension) in velocity
 nz=                    number of z samples (1st dimension) in velocity
 nxm=			number of midpoints of input traces		

 Optional Parameters:							
 dt= or from header (dt) 	time sampling interval of input data	
 offs= or from header (offset) 	source-receiver offset	 	
 dxm= or from header (d2) 	sampling interval of midpoints 		
 fxm=0		first midpoint in input trace				
 nxd=5		skipped number of midpoints (see note)			
 dx=50.0	x sampling interval of velocity				
 fx=0.0	first x sample of velocity				
 dz=50.0	z sampling interval of velocity				
 nxb=nx/2	band centered at midpoints (see note)			
 nxc=0		hozizontal range in which velocity is changed		
 nzc=0		vertical range in which velocity is changed		
 fxo=0.0	x-coordinate of first output trace 			
 dxo=15.0	horizontal spacing of output trace 			
 nxo=101	number of output traces 				",	
 fzo=0.0	z-coordinate of first point in output trace 		
 dzo=15.0	vertical spacing of output trace 			
 nzo=101	number of points in output trace			",	
 fmax=0.25/dt	Maximum frequency set for operator antialiasing		
 ang=180	Maximum dip angle allowed in the image			
 ls=0		=1 for line source; =0 for point source			
 pert=0	=1 calculate time correction from v_p[nx][nz]		
 vpfile	file containing slowness perturbation array v_p[nx][nz]	
 verbose=1              =1 to print some useful information		

 Notes:								
 Traveltime and amplitude are calculated by finite difference which	
 is done only in one of every NXD midpoints; in the skipped midpoint, 	
 interpolation is used to calculate traveltime and amplitude.		", 
 For each midpoint, traveltime and amplitude are calculated in the 	
 horizontal range of (xm-nxb*dx, xm+nxb*dx). Velocity is changed by 	
 constant extropolation in two upper trianglar corners whose width is 	
 nxc*dx and height is nzc*dz.						

 Eikonal equation will fail to solve if there is a polar turned ray.	
 In this case, the program shows the related geometric information. 	
 There are three ways to remove the turned ray: smoothing velocity, 	
 reducing nxb, and increaing nxc and nzc (if the turned ray occurs  	
 in the shallow areas). To prevent traveltime distortion from a over	
 smoothed velocity, traveltime is corrected based on the slowness 	
 perturbation.								

 Offsets are signed - may be positive or negative. 			




 Author:  Zhenyue Liu, 08/28/93,  Colorado School of Mines 

 Reference:
 Bleistein, N., Cohen, J. K., and Hagin, F., 1987,
  Two-and-one-half dimensional Born inversion with an arbitrary reference
         Geophysics Vol. 52, no.1, 26-36.