STATE OF THE ART PST INVERSION SOFTWARE PACKAGE
PAT is an integrated passive seismic tomography package for inverting P- and S-wave travel times for 3-D velocity and Poisson’s structure and micro earthquake locations. It uses an algorithm based on adaptive grid. The procedure of the data analysis is depicted in the following flow chart.
The PST inversion algorithm
The most critical part of any Passive Seismic Tomography (PST) survey is the algorithm that is used to invert the arrival times of the P- and S- seismic phases to reliable geological models. LandTech engineers have recently developed a new revolutionary inversion algorithm (PAT) that incorporates new ray tracers, the required for the 3D inversion initial model using seismic interferometry, seismic array processing and an expert system mechanism which increases the resolution by an order of magnitude.
PAT uses a user-friendly interface that is common in all the steps of the processing, from the initial model design to the final plots of the 3D tomographic results.
- The most usual data formats are supported.
- Data selection is performed by interactive tools and filters.
- Interactive design of initial tomography model.
- Tools for calculating the 1D minimum velocity model for use as initial model.
- Automatic Vp/Vs ratio calculation.
- An automatic parametrization system (adaptive grids) has been developed.
- Ray coverage and solution stability were taken into account for the automatic and optimal grid geometry design.
- Checkerboard testing.
- Synthetic anomalies resembling the geophysical targets can be interactively created and thoroughly tested.
- A highly interactive graphical interface can present in 3D perspective view all the structures estimated by the software.