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GLOBAL PATTERNS OF INTRAPLATE STRESS AND CONSTRAINTS ON SEISMICITY
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 1st International Congress of the Brazilian Geophysical Society, Nov 1989, cp-317-00063
Abstract
Regional patterns of present-day tectonic stress can be used to evaluate the forces acting on the lithosphere and to investigate intraplate seismicity. Preliminary analysis of a global stress database iridicates that most intraplate regions are characterized by a compressional·stress regime; extension is limited almost entirely to thermally uplifted regions. A dataset of well-constrained focal mechanisms of intraplate events in North America has been evaluated using independent information on tectonic stress orientations. Slip in most of these events was found to be consistent with reactivation of pre-existing structures in response to the regional stress field. Localized stress anomalies were not required to explain the the majority of the deformation.