Landslide component polygons of landslide features mapped across Tasmania, with summary landslide data derived from the Geohazards (Landslide) Database, Tasmanian Information on Geoscience and Exploration Resources (TIGER) system; administered by Mineral Resources Tasmania (MRT). A landslide is defined as a downslope movement of a mass of rock, debris or earth by a variety of failure modes (slide, flow, spread, fall, topple, or combinations thereof) â but excludes subsidence (such as karst areas). The summary landslide data includes: the landslide ID (database reference), the landslide component (polygon) mapped, the landslide name, the locality, the feature type (type of landslide entity mapped), the landslide classification, the activity state (âRecent or Activeâ or âActivity Unknownâ), the earliest known activity, related reports (largely MRT reports), related MRT plans. A Details field provides a link to a Landslide Details page where further information may be available.

The polygon landslide components and summary landslide data are derived from the Geohazards (Landslide) Database, Tasmanian Information on Geoscience and Exploration Resources (TIGER) system; administered by Mineral Resources Tasmania (MRT), Department of State Growth. The Geohazards (Landslide) Database was originally developed from information held in a records system (CARS) for land stability and groundwater investigations (1972-1993) conducted by engineering geology staff of the former Department of Mines, and later Mineral Resources Tasmania. The landslide data was captured in the TIGER system, as point data and non-spatial data, and expanded with the addition of landslide features shown on published landslide maps and geology maps. In 2003 the facility to store polygon data was added to the Geohazards (Landslide) Database and in 2008 line data was added. A large set of landslide polygon data was initially captured from landslide maps produced by MRT for the North-West Coast region in the Land Stability Hazard Mapping Project (Engineering Geology Land Stability Map Series, 1:25 000 scale); published in 1996-98 and revised in 2003. Since 2003 significant landslide data has been added to the Geohazards (Landslide) Database in support of the production of the Tasmanian Landslide Map Series. Additionally, the existing landslide data within these published map sheet areas has been revised and expanded. The methodology of this map series is described in the document "Tasmanian Landslide Map Series: User Guide and Technical Methodology" (Mazengarb, C. and Stevenson, M.D. 2010. Tasmanian Geological Survey Record 2010/01). Other landslide events around Tasmania are added to the database from time to time if MRT is made aware of them. The great majority of the landslide data presented is sourced from MRT records and mapping, but other external sources are utilised where available to MRT (e.g. reports by other State Government departments, reports supplied by Local Government, newspaper articles, etc.). This dataset will continue to expand with new mapping projects and as data is made available to MRT.

Positional Accuracy: The landslide polygon data initially captured in 2003 from the Land Stability Hazard Mapping Project (Engineering Geology Land Stability Map Series, 1:25 000 scale) generally has a much lower positional accuracy than subsequent polygon data. These simplistic polygons represent total landslide affected areas only, and are often only rough approximations of landslide zones or areas dominated by landslides. Since 2003, the polygon data has been added largely in support of the production of the Tasmanian Landslide Map Series, as well as some other detailed landslide mapping projects. Polygon data from within the areas of detailed mapping as part of the Tasmanian Landslide Map Series, which is published at 1:25,000 scale but mapped at a more detailed scale, will usually have a positional accuracy better than 10m. Much of the less accurate polygon data from the North-West Coast Land Stability Hazard Mapping Project (captured in 2003) that is within about 4-6km of the coast has since been revised or superseded by detailed mapping for the Tasmanian Landslide Map Series. Attribute Accuracy: The data held in the Geohazards (Landslide) Database, from which this dataset is derived, has been compiled from a range of sources, spanning several decades, with a range of mapping methodologies and mapping effort. As a result there are a range of attribute accuracies across Tasmania. As part of the compilation process for the Tasmanian Landslide Map Series, the data for all the landslides included in the detailed mapping has been checked by MRT geologists and all reasonable effort has been made to ensure these landslides are accurately located and attributed. For the first three map-sheets published in the Tasmanian Landslide Map Series (Hobart, Glenorchy and Launceston; 2004-05) only single polygons representing total landslide affected areas were captured for individual landslide features. Subsequent maps were produced with a range of more detailed landslide component polygon types to represent the various morphologically distinct parts of a landslide feature. Logical Consistency: The data held in the Geohazards (Landslide) Database, from which this dataset is derived, has been compiled from a range of sources, spanning several decades, with a range of mapping methodologies and mapping effort. As a result there is variation in the logical consistency of the data across Tasmania. Landslide data for all of the landslides included in the detailed mapping for the Tasmanian Landslide Map Series has been produced, or revised, to meet the requirements of map production at 1:25,000 scale. For these areas, in addition to visual checks, the GIS package (ArcMap) was used to check topological consistency in most cases. Other (non-spatial) relationships between the landslide data have also been revised and will be more consistent within the areas of detailed mapping in the Tasmanian Landslide Map Series. Completeness: The data held in the Geohazards (Landslide) Database, from which this dataset is derived, has been compiled from a range of sources, spanning several decades, with a range of mapping methodologies and mapping effort. As a result the completeness of the coverage, the attribution and the verification varies across Tasmania. Landslide data from within the areas of detailed mapping as part of the Tasmanian Landslide Map Series will generally be more complete. For the first three map-sheets published in the Tasmanian Landslide Map Series (Hobart, Glenorchy and Launceston; 2004-05) only single polygons representing total landslide affected areas were captured for individual landslide features. The majority of landslides existing within the areas of detailed mapping in this series where landslide component polygons were mapped will be included in the dataset up to the year of map publication, and the majority, but not all, have been verified during field visits by MRT geologists. The data for all of the landslides within these areas of detailed mapping has been checked by MRT geologists to ensure that it meets the necessary minimum requirements for landslide description. There will be many other unrecognised landslides in the landscape around Tasmania that are not included in this dataset, especially outside the areas of detailed mapping associated with the Tasmanian Landslide Map Series.