24 January 2010
Thanks to David Kwok of the Geotechnical Engineering Office in Hong Kong for highlighting this video to me, and for the image below.
On 18th June 1972 Hong Kong suffered an extraordinary landslide at Po Shan Road, in the Mid-Levels area:
The slide, which had a volume of about 40,000 cubic metres, induced the collapse of two large buildings, killing 67 people and injuring a further 20. The landslide understandably caused considerably soul-searching within Hong Kong, not least because major stability problems at the site had been identified nine months before the failure. A recommendation of the Royal Commission (Hong Kong was a British dependency at that time of course) was that a government agency should be established to manage slopes. This led to the formation of what is now called the Geotechnical Engineering Office (GEO), which has worked tirelessly and with considerable success to reduce landslide losses in Hong Kong.
In 2007 as part of its 30th anniversary celebrations, GEO produced this brochure. Much more information about their work, and about slope issues in Hong Kong, can be found on their slope safety website. There is little doubt that the approach has been successful (and should be repeated elsewhere – for example in Taiwan). This graph, taken from the brochure above, shows the trends in landslide losses before and after the establishment of GEO:
However, through all of their work they have not forgotten the importance of the Po Shan Road incident. Recently, they have produced a short video describing the event. Most interesting is a set of animations of the occurrence of the landslide, including its impact on the buildings. This is an impressive and useful illustration of the destructive power of even comparatively small landslides when they occur in urbanised areas, and of the need to maintain vigilance.
The video is available from the GEO download site at the following address:
I have embedded the video here – you should be able to play it by clicking on the video screen below: