Vel'Sor was a plain that existed beneath the fiery red sky of the planet Vulcan and was where the Sarek family held land for thirty generations. Sarek himself visited the area in 2311/2312 in order to visit the grave of his deceased wife, Amanda Grayson. (TOS novel: The Fire and the Rose)
The USS Vel'Sor was named for the area. (ST - Typhon Pact novel: Rough Beasts of Empire)