D. M. D. James writes: the mechanics of formation of polygonal faults are widely acknowledged as not yet fully understood and it is welcome that Goulty & Swarbrick (2005) attempt a discriminatory test between rival hypotheses. It is however important that such a test bears some relation to physical reality.

...

The ‘test’ is based on the assumption that the ratio of horizontal to vertical effective stress as deduced from leak-off tests in two wells in the North Sea at depths of about 2 km yields the co-efficient of earth pressure at rest therein and hence the residual friction governing the...

You do not currently have access to this article.