XN000022-1995-08-16 — Page 7

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Following the 1987 incident, the flat area at the slope toe was fenced off. Since then GEO has advised the Lands Department not to allocate the land for any use involving occupied structures, and to advise other potential users to take into account the previous instability of the slope when considering the suitability of the site for other purposes.

The failure on August 13 affected an area of the slope about 50 metres long and 30 metres high. The initial estimate of the volume is more than 5,000 cubic metres.

The detailed investigation now underway will explore all relevant information in order to obtain a full understanding of the causes of the failure. A specific objective of the investigation will be to examine why the volume of the landslip was much larger than foreseen and why the debris travelled as far as it did.

As regards the failure in Wong Chuk Hang, GEO said the hillside between Nam Long Shan Road and Shum Wan Road was modified by three types of man-made activity prior to the failure on August 13.

Near the crest of the landslip scar some cutting and filling of the original natural ground occurred during the construction of Nam Long Shan Road before 1945. A retaining wall on the outside edge of Nam Long Shan Road was removed by the landslip.

At the base of the hillside a small cut slope in weathered volcanic rock and soil was formed as part of the reclamation project for Po Chong Wan in 1978. It was registered as number 15NW-B/C77 in August 1984.

The slope was 84 metres long, with a maximum height of 10 metres, inclined at about 50 degree. As a roadside slope, it was classified as having a low to moderate consequence of failure. A short section of the southern part of the cut slope was not covered by debris from the recent failure. Most of the cut slope is now covered by the landslip debris. It is not yet known whether the cut slope had moved as part of the failure or stayed intact under the debris.

The failure on August 13 affected a large area of hillside. The width of the landslip scar varies from 65 metres to 90 metres and the height is about 70 metres. The current estimate of the volume is more than 20,000 cubic metres.

End/Wednesday, August 16, 1995