Sheet slides and rotational failures on a convergent margin: the Kidnappers Slide, New Zealand

摘要: The Kidnappers Slide, on the upper continental slope of convergent margin off eastern North Island, New Zealand, has been re-examined using a grid high-resolution seismic reflection profiles. slide is not single feature but complex sheet slides and rotational failures ranging from 20 to 140 m thick, covering total area 720 km2. Failures occurred in several phases, slopes 1–5°, late Quaternary, muddy, shelf-edge clinoforms that have prograded into an accretionary, trench-slope basin. Piston cores stratigraphy show main failure probably early Holocene times movements ranged mid last glacial times. The exhibit tensional collapse via numerous listric normal faults sole out glide planes; there no clear evidence compressional structures anywhere within complex. planes occur at progressively deeper stratigraphic levels towards northeastern end complex, near steep defines seaward edge There retrogressive top slope. surficial are being deformed by growth active tectonic folds associated with plate margin. This type may be partially related metastable sandy layers age progradational sequence, possibly formation bubble phase gas shallow depths. Failure was triggered earthquake loading sediments this highly region.