Fault Dilation

The default stress data comes from the World Stress Map (Heidbach et al., 2016), however, if you wish to use alternative stress indicators, then please click on the folder icon; the stress data needs to be in a .csv format with a schema similar to that of Heidbach et al (2016).

View/Edit Default Stress Search Parameters

This is the maximum radius that is used to search for stress data; the default for the tool is 200 km. If no stress data are encountered within this radius, the tool will fail. The search radius can be manually increased, but please note that results will be based on far-field stress data that are not necessarily representative of the Present Day stress field within the AOI.

As described in Section 2.2, the stress search algorithm evaluates the standard deviation of maximum horizontal stress indicators that are encountered within the search radius defined above. The search is limited to data for which this standard deviation reaches a maximum threshold; this threshold is defined in the ‘Maximum SHmax Azimuth Standard Deviation’ parameter field. By default, the tool uses a value of 25°, but the user can manually adjust this value (up to 180°) to include a broader range of azimuths in the calculation of average SHmax within the AOI.

The tool applies distance-weighting to encountered stress data within the search radius; this weighting is used in the calculation of Present Day average maximum compressive stress at each fault segment. By default, inverse distance weighting is used (i.e. weights are scaled by the inverse of distance from fault segments; this method may be manually changed to ‘linear’ or ‘none’ in the ‘Distance Weighting Method’ parameter field.

The application of distance-weighting starts at a specified distance from each fault segment. Stress data encountered within this distance radius are considered to be wholly representative of the stress field for that fault segment, so are not weighted. By default, tool uses a distance threshold of 0.1°, but this may be modified in the ‘Relative Distance Weighting Start’ parameter field.

The stress search algorithm used by the tool includes all stress indicator methods by default, where methods are recorded in the World Stress Map compilation. The ‘Exclude Stress Methods’ parameter field allows the user to exclude specific stress indicator method data from the fault dilation analysis. Method abbreviations are shown in the parameter field; a full name and description of the stress indicator methods is provided in the Appendix (Table 2 Stress Indicator Types).

Apply Stress Quality weights

These are the default settings for the stress quality weights and can be easily modified if required.

Apply Stress Method Weights

All stress indicator method weights can be modified from the default if desired (see Appendix Table 2 Stress Indicator Types).

Exclude Plate Boundary Stress Measurements

This box can be checked to exclude the regional tectonic influence of plate boundaries and adjacent tectonic plates. If checked, then a further stipulation can be made, which removes any stress data from the search algorithm within a specified distance of any plate boundaries.

If you have a pre-defined AOI polygon feature class then please add this using the folder icon. Alternatively, a custom AOI may be drawn directly onto the map using the pen icon; this will start an edit session.

If drawing your AOI, then a dialogue box will open, please click yes.

Once you have drawn the AOI, it will appear as a red polygon and the associated feature class is then automatically saved to your default geodatabase.

Result spacing refers to the distribution of points (and therefore raster grid size) for the fault damage score. The default spacing is 0.1° by default.

All outputs are automatically saved to the default geodatabase of an active ArcGIS Pro session. If you would like to use a different location, then click on the ‘folder’ icon. We do not recommend changing locations whilst in the middle of an ArcGIS Pro session, or a saved project (in which the tool has already been run), as it will not automatically add the new layers (due to output versioning).

For information on the rationale for making the Fault Dilation Tool, methodology, and interpreting results, please refer to the Fault Dilation Toll User Guide located in the Guides and Reports button on the Getech Ribbon.