Geotechnical analysis of the kidnappers slide, upper continental slope, New Zealand

Abstract

Abstract The Kidnappers Slide complex, on the 1–5° upper continental slope of eastern North Island, New Zealand, consists of several, very large translational slides and rotational slumps. They are of several Late Quaternary phases, range from 20 to 140 m thick, and cover a total area of 720 km2. The main, early Holocene (c. 8000–10,000 yr) phase involved a coast‐parallel sedimentary prism that was deposited on the outer shelf and upper continental slope at a rate of 1–3 m/1000 yr during the last glacial age. Irregularly blanketing the slump, and also locally slumped, is the thin, outer edge of the post‐glacial (< 16,000 yr) prism, deposited on the upper slope at rates ranging from 0.3 to 0.7 m/1000 yr. The sediments consist essentially of terrigenous hemipelagic olive gray mud, along with minor sandy mud, volcanic ash, and pumiceous mud. They are low in calcium carbonate and are inorganic, with high plasticity and low sensitivity. Minor variations occur in the mass physical properties of the post‐glacial...