c program recfunk <br> 
c 9/26/00 JJP <br> 
c multitaper program to invert for receiver functions <br> 
c SINGLE STATION WITH SPECTRAL WEIGHTING <br> 
c "Multiple Taper Correlation" (MTC) Receiver functions are described in <br> 
c <br> 
c Park, J., and V. Levin, Receiver functions from multiple-taper spectral <br> 
c correlation estimates, Bull. Seismo. Soc Amer., in press 2000. <br> 
c PREPRINT:  http://www.geology.yale.edu/~jjpark/recfunk.pdf <br>
c <br> 
c spectral estimates of pre-event noise <br> 
c weight the inversion in the frequency domain, thereby avoiding the <br> 
c usual problem with microseism noise in 0.1-0.5 Hz <br> 
c <br> 
c the main advantage of MTC is not the noise damping, however -- the <br> 
c cross-correlation of the horizontal and vertical components is used <br> 
c in place of spectral division when estimating the RF. <br> 
c this approach appears to be more stable and gives RF-uncertainties <br> 
c in the frequency domain that are useful for stacking. <br> 
c <br> 
c this version of the RF code reads a file of data filenames and time intervals <br> 
c  the data must be SAC format with horizontals rotated to radial & transverse <br>
c the file is "in_recfunk" and has lines of the form: <br> 
c <br> 
c 1997.070.19.33.bh? <-- code replaces ? with r,t,z <br> 
c 57 52 <-- start time of analysis window, window duration (sec) <br> 
c 1997.076.08.15.bh? <br> 
c 62 62 <br> 
c ... <br> 
c ... <br> 
c ... <br> 
c stop <-- tells code that data is finished, 599 events max <br> 
c <br> 
c code does NOT combine data with different sample rates <br> 
c data files limited to 15K pnts. To increase, see common block /datastuff/ <br> 
c <br> 
c many intermediate quantities are plotted with PLOTIT as the code proceeds. <br> 
c other intermediate quantities can be plotted by uncommenting calls to PLOTIT <br> 
c <br> 
c the program computes RFs in the Freq domain for multiple records <br> 
c then it computes composite RFs that are dependent on either <br> 
c Back-azimuth or epicentral distance. The standard bin width is 10 degrees <br> 
c with stacked RFs computed every 5 degrees. You can change this in the code. <br> 
c RF are not migrated in this process, so the user is prompted for parameters <br> 
c that narrow the focus of the stacks <br> 
c e.g. a BAZ-sector over which to compute an epicentral RF profile. <br> 
c <br> 
c the PLOTIT graphs of RF sweeps can be improved upon, natch <br> 
c the code writes the BAZ- and EPICEN-dependent RFs to files <br> 
c in a format easily digested by GMT (traces are separated by ">" lines) <br> 
c <br> 
c filenames: out[rt]_baz.grid out[rt]_epi.grid <br> 
c <br> 
c these files are overwritten everytime you run the program <br> 
c so rename them to save them <br> 
c <br> 
c to compile recfunk: <br> 
c <br> 
c xf77 -o recfunk recfunk.f plotlib <br> 
c <br> 
c The "-fast -native" option will generate a faster executable. Note that <br> 
c <br> 
c alias xf77 'f77 -I${OPENWINHOME}/include -L${OPENWINHOME}/lib -lxview -lolgx -lX11' <br> 
c <br> 
c plotlib is PLOTIT plotting package, used to plot results thruout the code <br> 
c PLOTIT resides at love.geology.yale.edu FTP site at pub/park/Plotxy <br> 
c <br> 
c EISPACK routines TINVIT and TRIDIB compute Slepian tapers for spectrum analysis <br> 
c <br>