sfricker1 implements 1-D convolution with the Ricker wavelet.

The following example from

rsf/rsf/wedge shows convolution modeling with a wedge model using

**sfricker1**.

The convolution is implemented in the frequency domain, where the Ricker wavelet takes the form

$\text{F(}\text{\omega}\text{)}=\frac{{\text{\omega}}^{2}}{{\text{\omega}}_{0}^{2}}\mathrm{\text{exp}}\left(-,\frac{{\text{\omega}}^{2}}{{\text{\omega}}_{0}^{2}}\right)$
The peak frequency

${\text{\omega}}_{0}$ can be specified either in hertz (with

**frequency=** parameter) as a fraction of the Nyquist frequency (with

**freq=** parameter).

Optionally, it is possible to combine the Ricker wavelet with a half-order derivative filter using

**deriv=y**.

### 10 previous programs of the month:

sfpwd implements plane-wave destruction, a filter that attenuates locally plane-wave events, as described in the paper Applications of plane-wave destruction filters. The following example from jsg/diffr/gom shows a seismic section before and after an

Weblog:Madagascar development blogTracked:Feb 09, 16:19sfpow multiplies the input data by a gain function of the form Gx1x2…,xn=x1p1x2p2⋯xnpn The powers p1,p2,…,pn are given by pow1=, pow2=, etc. parameters. For backward compatibility, sftpow tpow= is an alias for sfpow pow1=. The following examp

Weblog:Madagascar development blogTracked:Mar 11, 09:01sfnmo implements normal moveout (NMO) correction, one of the most fundamental operations in seismic reflection data processing. The following example from jsg/avo/avo shows synthetic data before and after NMO correction. NMO transforms presta

Weblog:Madagascar development blogTracked:Apr 08, 06:02sfvscan implements seismic velocity analysis by scanning stacking velocities. This transformation is also known as the velocity transform or the hyperbolic Radon transform. The following example from bei/vela/vscan shows an example for transforming a C

Weblog:Madagascar development blogTracked:May 11, 12:25sfwiggle plots data using the traditional seismic method of wiggly traces. The following example from rsf/rsf/rsftour shows a typical output: Similarly to other plotting programs, there are multiple parameters that control the output. For examp

Weblog:Madagascar development blogTracked:Jun 12, 10:51sfwiggle plots data using the traditional seismic method of wiggly traces. The following example from rsf/rsf/rsftour shows a typical output: Similarly to other plotting programs, there are multiple parameters that control the output. For examp

Weblog:Madagascar development blogTracked:Jun 12, 10:59sftime2depth converts the input from vertical time to depth coordinates. The following example from rsf/su/rsflab9 shows a seismic image converted from time to depth by this transformation: The example is borrowed from John Stockwell's lecture not

Weblog:Madagascar development blogTracked:Jul 01, 22:28sftime2depth converts the input from vertical time to depth coordinates. The following example from rsf/su/rsflab9 shows a seismic image converted from time to depth by this transformation: The example is borrowed from John Stockwell's lecture not

Weblog:Madagascar development blogTracked:Jul 01, 22:29sfai2refl converts acoustic impedance to normal-incidence PP reflectivity using the simple equation R(t)=I(t+Δt)-I(t)I(t+Δt)+I(t) The program is useful for convolution modeling. The following example from rsf/rsf/wedge shows a classic e

Weblog:Madagascar development blogTracked:Aug 02, 15:22sfpatch breaks the input data into local windows or "patches", possibly with overlap. The patching technique is explained by Jon Claerbout in Nonstationarity: patching chapter from Image Estimation by Example. Suppose you have a 1-D signal with

Weblog:Madagascar development blogTracked:Sep 14, 12:33sfremap1 interpolates the input data to a different grid along the first axis. Here is an elementary example: making some data and interpolating it to a denser grid bash$ sfmath n1=5 o1=0 d1=1 output=x1 | sfdisfil 0: 0 1

Weblog:Madagascar development blogTracked:Nov 03, 06:22