Wednesday, May 15, 2024

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Franschhoek is a captivating series of landslides located in South Africa.


Dave Petley, a renowned expert in the field of landslides, is the author of The Landslide Blog. He is highly regarded for his contributions to the research and control of landslides.

Image of a landslide partially covered with a transparent sand-colored overlay and the words “The Landslide Blog,” centered, in white

In the past, I have not often covered landslides in South Africa. However, during the weekend of September 23-24, 2023, heavy rainfall from a storm caused multiple slope failures in the country. The most significant amount of precipitation (299 mm) was recorded in Franschhoek, which has coordinates of -33.897 latitude and 19.152 longitude.

Due to this, several landslides occurred in Franschhoek, causing damage to roads and structures. Franschhoek life shared a series of aerial photos on Twitter, taken by Jean Tresfon and uploaded on Facebook, showing the aftermath of the landslides.

The Facebook images below display the most intriguing sites, featuring multiple landslides.

The image above displays several occurrences of debris flows that seem to have taken place at the coordinates [-33.880, 19.091]. The location is also depicted in the Google Earth picture below.

Google Earth image of the site of the landslides at Franschhoek in South Africa.

The Franschhoek landslides in South Africa captured in a Google Earth image.

These appear to be excellent illustrations of minor, superficial landslides in eroded rock that have carried material downhill. In the context of Hong Kong, these would be referred to as unconfined slope flows as they have not formed into channels. It is worth noting the significant distance of the runout. It is evident that the slope has been deforested in recent times. The landslides began above this location, but it is possible that the removal of trees may have played a role in the extent of the runout. There is a considerable amount of material being carried along this section of the slope.

Elsewhere in Franschhoek, landslides took place. According to News 24, a well-known person had to leave a building due to a mudslide at the MontMartre estate. The article features pictures of the chalet’s destruction.

Go back to The Landslide Blog homepage.

Text © 2023. The authors. CC BY-NC-ND 3.0

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