Abstract

Assuming only that slip occurs in the direction of resolved shear stress on fault planes, we have found a wide range of uniform stress tensors, each of which is consistent with ten diverse focal mechanisms for recent moderate-size earthquakes in New England and vicinity. Thus, it is possible that the variations in focal mechanisms are due to the occurrence of specific pre-existing zones of weakness rather than to inhomogeneous stresses. Acceptable stresses are broadly consistent with those established for other parts of the eastern United States—namely, northeast- or east-northeast–directed maximum compression and nearly vertical minimum compression.

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