Proceedings of the 12th International INQUA meeting on paleoseismology, active tectonic and archaeoseismology

windows before being destroyed in the process of uncovering adjacent sections of the fault. Structural measurements included taking the strike and dip of the local fault plane, trend and plunge of the slickenline features. Where curved slickenline tracks were observed, multiple trend and plunge measurements were made to adequately sample the curvilinear slip path, and the lengths of the track segments were measured. When working by hand, we found that the deeper sections of the fault were more easily exposed than fault surfaces closer to the former ground surface, and that the uppermost parts of the fault, which cuts the soil and other loose surficial materials, and was often water saturated, typically did not preserve slickenlines well. We found best results were achieved by first removing 1-2 m of surficial material from above the fault before commencing stages 2 and 3. This way, we could access more compact fault plane material that was ~4 m below the former ground surface. Fig. 3: Finding the fault zone of the Kekerengu Fault. Red arrows show the location of the Kekerengu fault plane. R E S U LT S Despite the limited width of the fault plane exposed at any one time during our excavations, 42 individual slickenline observations were made. Due to the small window of observation, slickenline length was at most 10-20 cm. While linear slickenlines were most common, a few demonstrably curved ones were also documented, most of which were less than 10 cm long. Figure 4D shows examples of curved slickenlines found on the Kekerengu Fault during this study (Figs. 4A and 4D). These new observations show the same sense of convexity (convex up) as slickenlines that were seen at the same locality on naturally exposed free faces of the Kekerengu Fault immediately after the 2016 earthquake (Fig. 4B and 4C). Slickenlines that were artificially exhumed during this study were mostly pitching to the southwest on steeply- northwest- dipping fault planes, with a minority found to be pitching to the northeast, in agreement with naturally exposed slickenlines from the Kaikōura earthquake (Fig. 4A). At Shag Bend, where no post- earthquake slickenlines were documented, and which is located 10 km to the southwest of the other two sites, we documented slickenlines with the same sense of curvature.