Last year Dominique Simillox-Tohon (KULeuven) had identified by resistivity several faults within the ancient city that may have been the result of the devastating mid-seventh-century earthquake which extinguished Sagalassos. This week, together with archaeologist Hannelore Vanhaverbeke (KULeuven), he carried out a test excavation on the slopes to the north of the Zeus Temple and the Northwest Heroon in search of more evidence for the presence of an active normal fault at the northern part of ancient Sagalassos. Previous research already provided several arguments for the presence of this fault, but no structural evidence can be seen on the surface of the limestone cliff behind Sagalassos. This absence was, up to now, explained as the result of intense erosion of the limestone cliff; intense degradation of fault planes in limestone has been observed elsewhere in the territory of Sagalassos. So Dominique and Hannelore excavated a trench perpendicular to the eastern part of the NW necropolis, which is interpreted as a degraded active normal fault plane. Apparent in both the east and west profiles of the trench was a man-made dump, probably resulting from a clearing operation in the NW necropolis above the steep limestone slope. It was dug within an older colluvial layer with a high concentration of archaeological material (mainly ceramics and bone and, to a lesser extent, glass and metal). A hardened, compacted thin (10-15 cm) layer is sandwiched between the dump and the fault plane. Many ceramics and some limestone fragments of this layer are rotated and trapped along the plane. This layer could be followed through the entire test trench to its bottom, some two meters deep. The archaeological material of this narrow zone and the dump is similar in morphology and date. The compacted layer is interpreted as a shear zone. We believe that because of normal faulting, a shear zone along the fault plane was compacted this layer and reoriented the ceramics and limestone fragments in the dump and underlying layers. Above the dump in the east profile there is a wedge shaped, more lightly colored layer with bigger limestone fragments. We believe this is a colluvial wedge, the result of degradation of the newly formed fault scarp. This layer is not clearly observed in the western profile. In both profiles it seems that the top of the sheared part of the dump is located some 30 cm higher than the top of the undeformed dump. This possibly reflects the minimum displacement of the faulting event and will enable us to define a magnitude for it. This faulting has to post-date the emplacement of the dump and indicates historical activity, possibly corresponding to the archaeoseismological data at Sagalassos. All observations suggest a historical reactivation of the whole Sagalassos fault zone (main fault and secondary fault). Samples of the different structural elements of the main fault zone will be taken for further microstructural analysis. Also, the flowstone will be sampled for a possibly better dating of the fault events.