Suburbs with mapped landslip hazard

87 of the 1,264 Australian suburbs published on this site have a landslip hazard band mapped across part of them. That is a count of our own published pages, not of every suburb in the country — the corpus grows, and this page is rebuilt with it. Every one is in Tasmania. That is not because landslip risk stops at the border — it is because Tasmania is the only state in this dataset that publishes landslip hazard as a mapped band we can read per suburb. Elsewhere the risk may be handled by a council overlay, by the building surveyor, or not mapped at all.

The consequence is procedural and it is front-loaded. A block inside a mapped band needs a geotechnical investigation before a permit can issue, and the report can change the footing design, the retaining, the siting of the house, or all three. Unlike most mapped constraints this one cannot be designed around after the fact, because the design depends on what the report says.

83 of these suburbs carry more than one band, which usually means the land rises across the suburb rather than that anybody disagrees about the risk. Which band covers a particular block is an address-level question.

4 of the bands describe an assessed hazard level. 2 describe a slope instead — land outside the assessed areas, categorised by gradient. Those two are not the same statement. An assessed band reflects a judgement about the ground; a slope band reflects the angle of it, and the assessment is the thing still to be done. Both land you in the same place procedurally: a report before a permit.