1.Introduction

STK is a tool for seismic data processing; basically it allows to:

Data format : SAC ASCII and SAC_Bin format are available; it can read until 2000 files (tested with 120)
Filtering the data: all filters are causal recursive IFR (Infinite Impulse Response) written using the bilinear Z-transform in the time domain. Their conception using a few number of coefficents gives them very fast with a low memory cost. The adaptation factor of frequency warants no deformation in the frequency domain of the transfert function. The main filters used are the following: Butterworth High-Pass and Low-Pass (n order), Farrer 10s-6s Low-Pass (a combination of rejector and Low-Pass specially designed for removing oceanic noise), Integrator, Derivator, Integrator with cut-off frequency, Derivator with cut-off frequency, Trend removing, Rejector (n-order), Envelop with Hilbert (not recursive at all), compensator of (n-order), Polynomial filter (n-order, not recursive at all ).

Data plotting : channel by channel, all channels, zoom, unzoom, unfilter, instantaneous time and amplitude informations with mouse pointer

Fourier domain: Power Spectral Density (PSD) in linear-linear, log-log axes; independant windows for each channel, instantaneous frequency and amplitude informations with mouse pointer, zoom, unzoom of spectra. Dirac, Hilbert transform, Time-Frequency representation (tested until 1 million of points per channel on 3 channels.

Polarization : easy and fast particule motion representation in both horizontal plane and incidence plane, with automatic computation of best direction with eigen vectors of the covariance matrix. Display of linearity and planearity coefficient.

Evolutive polarization: it is computed on a moving window; you can adjust the window length, the step, and choice many filters.

Legal terms

STK is distributed under the terms of the GNU General Public License.