A review of the classification of landslides of the flow type

As a result of the widespread use of the landslide classifications of Varne s (1978), and Hutchinson (1988), certain terms describing common types of f low-like mass movements have become entrenched in the language of engineeri ng geology. Example terms include debris flow, debris avalanche and mudslid e. Here, more precise definitions of the terms are proposed, which would al low the terms to be retained with their original meanings while making thei r application less ambiguous. A new division of landslide materials is prop osed, based on genetic and morphological aspects rather than arbitrary grai n-size limits. The basic material groups include sorted materials: gravel, sand, silt, and clay, unsorted materials: debris, earth and mud, peat and r ock. Definitions are proposed for relatively slow non-liquefied sand or gra vel flows, extremely rapid sand, silt or debris flow slides accompanied by liquefaction, clay flow slides involving extra-sensitive clays, peat flows, slow to rapid earth flows in nonsensitive plastic clays, debris flows whic h occur in steep established channels or gullies, mud flows considered as c ohesive debris flows, debris floods involving massive sediment transport at limited discharges, debris avalanches which occur on open hill slopes and rock avalanches formed by large scale failures of bedrock.