South Sister St. Marys, Tasmania

South Sister

landslides

NORTH-EAST FACING SLOPE ABOVE AND BELOW DUBLIN TOWN ROAD
Attachment 1
David Stapledon

PARTICULAR QUESTIONS

  1. What are the character and orientations of bedding and structural defects in the Triassic rocks downslope from Slides A and B failure surfaces?
  2. Is there evidence that the beds in any place have been tilted or rotated?
  3. What are the likely orientations, depths and characters of the Slides A & B?
  4. What are the likely ages of the most recent movements of Slides A & B?
  5. Is it likely that the Slides A & B moved initially at the same time?
  6. Is the graben feature 'real' and are there at Slide B, any other well or poorly preserved landslide-induced features?

ACTIVITIES

At the Graben feasture at Slide B
Record the position of the graben feature more precisely.
Record the size, shape and other relevant characterstics of the graben feature, by means of photos and a plan and cross sections on a suitable scale, say 1:100.
Use a garden spade to explore the graben sides and floor in several places, and record the results in detailed logs, and photos.

Elsewhere (See Mapping Areas)
Geological and geomorphic sketch-mapping. This to involve

  1. locating and plotting all exposures of insitu or near-insitu (?disturbed) bedrock, recording for each, the rock type and attitudes of bedding and any structural defects, and
  2. locating and plotting the positions and characteristics of any of the kinds of features listed in Appendix S of my Proof of Evidence.
    I suggest that the investigator should use a 1:2500 scale field sheet formed by tracing the contours from an enlargement of the 10m contour interval plan used for Figure 1 of my Proof of Evidence. As well as this 1:2500 plotting, he/she should use more detailed sketches and photos, to illustrate and support interpretations of particular features.

Mapping areas

  1. Whole of the NE section of Dublin Town Road.
  2. The slope below the road, everywhere down to RL540, and down to RL500 below Slide B.
  3. The north trending track or minor road, where it passes downslope of Slide B.
  4. The eastern fork of Yorkys Creek gully and downstream along it to at least the 18 degree dip measurement shown on the St Marys Sheet (Appendix P of my Proof of Evidence).
  5. The whole of Slide B as sketched on Figure 1 of my Proof of Evidence.
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3231 (1, 1, 3, 34)