Slip distribution of the Lake Tennyson earthquake, New Zealand, as inferred from static stress changes and off fault aftershocks

The fault plane of an earthquake can be estimated in many different ways. O ne is to examine the distribution of a well located aftershock sequence to see if a fault plane is evident. Here we present a new method where we take an earthquake aftershock sequence with distinguishable off fault clusters and vary the slip distribution to achieve a good correlation between region s of increased Coulomb failure stress (CFS) and aftershock occurrence. We f ind with the Lake Tennyson earthquake that simply taking an area outlined b y aftershocks to estimate a fault plane may not be valid. If we do this, pa tterns of increased CFS have negative correlation with off-fault aftershock occurrence. However if we restrict slip to only deeper regions, and over a smaller area, then the correlation between regions of increased CFS and af tershock off-fault occurrence is good.