split node fault data; this line repeats nfnodes times; omit entire block if nfnodes is zero. Each line includes the following information:

(i) node number -- global node number of this split node.
(ii) fault "B-vector" -- unit vector (normalized to length 1.0) pointing in the plane of the fault and perpendicular to the slip vector. Use the right-hand-rule as illustrated below to determine which of the two possible orientations to choose.
(iii) fault slip "S-vector" -- unit vector (normalized to length 1.0) pointing in the direction of slip on the side chosen to be positive. As implied by the illustration, positive slip is applied to the side of the fault containing "S cross B" in the right-hand-rule sense, while slip of the opposite sense will be applied to the "-S cross B" side of the fault.
(iv) fault dislocation full amplitude -- this is the amount of dislocation slip applied across the fault. Note: It is NOT the half-amplitude, as was the case in versions of GeoFEST prior to 4.3!

Also note that whereas earlier versions of GeoFEST terminated the split node list with "0 0", that is no longer the case! The list includes *NO* special terminating string.

example:

(a)         (b)                (c)           (d)
14     0.0  0.0  -1.0     0.0  1.0  0.0      0.4

(a) node number -- global node number of this split node.
(b) B-vector -- in this case pointing in the -Z direction.
(c) S-vector -- in this case pointing in the +Y direction.
(d) Slip amplitude -- in this case, 0.4 (displacement units).

Note that even in 1- and 2-degree of freedom problems, three vector components are used to specify the B and S vectors. In such cases, the Z-direction is assumed to be the out-of-plane direction, with positive being defined by "X cross Y". For example, a strike slip problem with ndof=1 would have S-vector in the Z-direction; a thrust fault with ndof=2 would have B-vector in the Z-direction.

First figure below illustrates the numbering used for the three split nodes in this example:

The second figure illustrates the right-hand-rule convention used for defining the direction of the B-vector for a given fault orientation and sense of slip: