Introduction

The motivation behind this analysis was the relatively simple-minded observation that while local stress azimuth measurements tend to be quite uniformly quasi-parallel, this quality does indeed diminish at long distance. Therefore in the interest of determination if this was a simple result of distortion of linearity due to map projections, or a real correlation of the data due to larger processes, the maps had to be made.

While it is still unclear what the physical meaning of this locus is, or whether or not is is reasonable to perform the analysis on data originating in differing stress regimes (as described by (1)), the data are showing a focusing that I believe needs a plausible explanation. Whether this explanation will involve a ridge-push mechanism after (8), basal drag from mantle circulation after (10), glacial rebound or, most likely, regional differentiation of a combination of all of these (and more).

It is my belief that the next step in such research is to produce many map subsets and overlay these with maps of various other geologic observations to search for clues as to the underlying source of these patterns. Hotspots, active margins, subduction, retreated glaciation, collision zones, triple junctions, failed third arms, and more could all contribute to such long-scale intra- and inter-plate stress transmission of stress. In the long-shot category I would even hazard that we could gain incite into back-arc spreading and Chinese energy flux centers.

 

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Figure 1 WSM down-loadable at ref'd web site. Legend not included to minimize business. Notice convergence zones in east Africa and coast of Norway. Legend not included to minimize business: Colors denote stress regimes, symbols denote methodology of measurement.