The SISZ is situated between two sections of the mid-Atlantic ridge, the Reykjanes ridge (RR) and the eastern volcanic zone (EVZ). Even though the angle between the SISZ and the neighbouring ridges is far from 90, it is considered as a transform fault. Following the transform fault hypothesis, left-lateral shear stress is expected along the E-W striking zone. This is equivalent to right-lateral shear stress with N-S orientation. In fact, earthquakes seem to occur on N-S trending en-echelon faults [20,30] and further references there). They are located side by side between the Hengill triple junction, where the RR meets the low activity western volcanic zone (WVZ) and Hekla volcano, a part of the EVZ  and Figure 27). As we further know from Subprojects 4 and 5, the orientation of the larger horizontal principal stress is NE-SW, i.e. fits to an active N-S or E-W trending fault, which is not a weak fault like the San Andreas fault, and the stress orientation seems to be constant since Pliocene time.
In detail, the questions to be solved are:
The area investigated extends from 18 to 24W and from 63 to 65N. The origin is set to 24W, 64N (cf. Figure 28) it includes the SISZ, north and south of 64N, the SW edge of the EVZ, and the north eastern most part of RR.