Surface breakthrough of a basement fault by repeated seismic slip episodes: The Ostler Fault, South Island, New Zealand

The Ostler Fault is one of the major active reverse faults in the piedmont of the Southern Alps, SE of the Alpine Fault. We present a new geological and morphotectonic map of the southern Ostler Fault, integrated with two seismic reflection profiles across the active central segments of the fault. Segmented, subparallel scarps define a N‐S belt (∼40 km long and 2−3 km wide) of pure reverse faults, which upthrow and back‐tilt a panel of Plio‐Pleistocene terrestrial units (2.4−1.0 Ma) plus the overlying glacial outwash (