A Note on the Modeling module

The Modeling module can be used to perform direct and inverse modeling of geodetic data, InSAR and GPS, through analytical models suitable for tectonic, volcanic sources and nuclear explosions.

The main module features are:

•Sampling Area definition: used to define the areas and the resolution to sample raster images;

•Image Subsampling: used to create the point vector dataset, used in the inversion, from raster images;

•Automatic Inversion: used to create automatic modeling performing both non-linear and linear inversion sequences to determine the slip distribution of a seismic event;

•Non-Linear Inversion: used to infer the best-fit source parameters through a non-linear optimization algorithm;

•Linear Inversion: used to find the slip/opening distribution through linear inversion;

•Forward Modeling: used to generate geocoded or slant range surface displacement maps due to tectonic or volcanic sources;

•CFF Stress Transfer: used to calculate the stress change induced between sources.

The Modeling module offers also a set of related tools:

•Moment Tensor calculation: used to calculate the moment tensor from a tectonic source and draw its beach-ball mechanism;

•LOS Projection: used to project into the Line-of-Sight the East/North/Up components of the displacement, optionally adding orbital contributions and getting wrapped output.

Two types of geodetic datasets are currently supported:

•InSAR dataset derived from the sampling of an unwrapped and geocoded displacement map;

•GPS dataset created off-line and stored in a shapefile format.

Three types of analytical sources can be currently handled:

•Shear and/or tensile dislocation for a rectangular source in a homogeneous and elastic half-space: this source has a double implementation: with a single and distributed dislocation;

•Point pressure source in a homogeneous and elastic half-space;

•Nuclear explosion: totally based on the point pressure source, but adopting kilotons instead of volume variation

The module allow a flexible handling of the coordinate systems: geodetic datasets with different systems (UTM or Lat/Lon) can be arbitrarily mixed and the user can set the desired coordinate system for the output sources.

Non-Linear inversion, Linear Inversion, Forward Modeling and CFF Stress Transfer panels are based on the XML Project File, an ASCII file in XML format where the information about the input/output data, sources and processing options are stored, allowing an easy recovery of the modeling session. The data are stored in different XML sections, so you don't need to create a project file for every panel.

A tutorial based on InSAR data for the 2003 Bam (Iran) earthquake can be used to explore the module functionalities.

Displacement Modeling - Overview

Displacement Modeling - Overview

A Note on the Modeling module