The Stress State of the Earth's Lithosphere: Results of Statistical Processing of the World Stress-Map Data

A method for the statistical processing of the input data on the stress state of the Earth's lithosphere that takes the initial 3-D position of the principle stress axes into account is elaborated. This approach is based on the calculation of the arithmetic mean value for every six independent tensor components during determination of the average stress in any sampling. When determining the sampling for calculation of the average stress for the current cell of the calculated grid, it is proposed to insert the measurements into the sampling that are spatially located in such a manner where the distance from the measurement point to the cell center is less than some value that is named as a search radius. The latter either was specified as a constant for all cells of the calculated grid or was determined assuming that the dispersion of the average tensor was less than some preset value. The results of the application of this approach are presented based on the example of the processing of the measurements from the World Stress Map (Heidbach et al., 2008). The resultant set of the mean stress-field maps reflects the generalized pattern of the stress distribution in the Earth's lithosphere.