Planet Labs images of the landslides at Franschhoek in South Africa
The author of The Landslide Blog is Dave Petley, an expert in the field of landslide research and control.
Recently, I shared information about a series of landslides caused by intense rain in Franschhoek, South Africa on September 23-24, 2023. Thanks to my friends at Planet Labs, I have received a high-quality SkySat image of the area to share with you.
On October 3, 2023, an image of the Franschhoek site was captured, revealing several landslides.
On October 3, a SkySat image captured multiple landslides in Franschhoek, South Africa. The image was provided by Planet Labs PBC.
The picture displays four primary regions where landslides originated, all of which seem to have started as shallow collapses in a thin layer of soil or regolith. A closer examination of the three higher altitude failures reveals this clearly:
An image taken on 3 October by the SkySat satellite reveals the source regions of three of the numerous landslides in Franschhoek, South Africa. The image is provided by Planet Labs PBC.
The origin of the landslide to the west is surprisingly small. In every instance, this initial minor collapse has caused soil and rock from the lower slopes to be carried along, resulting in a substantial flow. It seems that the two landslides in the middle have combined, resulting in a significantly long distance travelled.
However, Sarah Bates at Planet labs correctly identified that there is greater subtlety in these landslides than might be initially apparent. This is an image collected before the rainstorm, in this case on 13 September 2023:-
On September 13, 2023, an image was taken by Planet Labs PBC at Franschhoek in South Africa, showing the location of several landslides.
Surprisingly, this picture reveals that one of the main landslides had already taken place before the September 2023 rainstorm hit the region. As a result, the fields suffered significant damage. Satellite imagery can be utilized to gather data on the timing of this initial landslide, which cannot be seen in an image taken on June 6th, 2023.
The location of the numerous landslides in Franschhoek, South Africa. Photo taken on June 6, 2023. Photo credit: Planet Labs PBC.
However, it was captured in a photograph taken on June 22, 2023.
The Franschhoek region in South Africa experienced multiple landslides, as captured in this image taken on June 22, 2023 and provided by Planet Labs PBC.
According to recent news, there was significant rainfall in South Africa on June 14, 2023 which resulted in extensive destruction. The news also mentioned that the Franschhoek pass was shut down due to rockslides.
Reference
Planet Labs is a company based in San Francisco, CA that offers the Planet Application Program Interface (API) for PBS 2023, which aims to use space technology to support life on Earth. The company’s website is https://www.planet.com/.
Text © 2023. The authors. CC BY-NC-ND 3.0
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