Tectonics
As you can see in the image below, Cape Town is located quite in the centre of the African Plate. The African Plate shares boundaries with 7 other plates: The Eurasian plate, North American Plate, South American Plate, Arabian Plate, Indian Plate, Australian Plate and the Antarctic Plate in the South.
Image: Plate tectonics [Image]. (n.d.). Retrieved from http://pubs.usgs.gov/gip/dynamic/slabs.html
It seems that as Cape Town is located in the central region of the African Plate that it has no relation to any plate boundaries. However this is not that case as the African Plate is actively splitting! The African Plate is actively splitting itself into two tectonic plates by the East African Rift, which is an active continental rift zone in which a divergent tectonic plate boundary is in the process of developing.
The two new tectonic plates that are developing are called the Nubian Plate (Western half) and the Somali Plate (Eastern Plate), as you can see its location in the map below. Cape Town is located near the Nubian-Somali boundary, so tectonic boundaries may not be a foreign issue in the future.
It seems that as Cape Town is located in the central region of the African Plate that it has no relation to any plate boundaries. However this is not that case as the African Plate is actively splitting! The African Plate is actively splitting itself into two tectonic plates by the East African Rift, which is an active continental rift zone in which a divergent tectonic plate boundary is in the process of developing.
The two new tectonic plates that are developing are called the Nubian Plate (Western half) and the Somali Plate (Eastern Plate), as you can see its location in the map below. Cape Town is located near the Nubian-Somali boundary, so tectonic boundaries may not be a foreign issue in the future.