Change in stress directions along the central Denali fault, Alaska after the 2002 earthquake sequence

[1] On the basis of earthquake focal mechanisms, the state of stress along the central Denali fault, Alaska system changed after the 2002 earthquake sequence. Before the earthquake sequence, the maximum stress (sigma(1)) was at a 60degrees angle with the Denali fault west of the point of its maximum curvature, fault-normal between the fault apex and the Totschunda strand, and at 50degrees with respect to the Totschunda fault. In the epicentral region, the post-event sigma(1) has rotated counter-clockwise. Along the rest of the rupture zone the sense of rotation is clockwise. The sigma(1) direction became nearly fault-normal along the Totschunda strand. Along the central part of the rupture, sigma(1) is overrotated with sigma(3) being nearly vertical, promoting reverse aftershocks. This could be an indication of dynamic overshoot.