Digby – the key issue may not be noise on the common property, because in the case of noise it has to interfere with a resident’s reasonable enjoyment of their property. The OP indicates that vibrations/noise are an issue, but this may be difficult to prove. It is much easier to go the other route I suggested.
The essential element is that children should not be allowed in an area like that unsupervised, and they certainly shouldn’t be riding skateboards. The model by-law that deals with that is:
(1) Any child for whom an owner or occupier of a lot is responsible may play on any area of the common property that is designated by the owners corporation for that purpose but may only use an area designated for swimming while under adult supervision.
(2) An owner or occupier of a lot must not permit any child for whom the owner or occupier is responsible, unless accompanied by an adult exercising effective control, to be or remain on common property that is a laundry, car parking area or other area of possible danger or hazard to children.
Schemes usually have by-laws that are similar. Even if there isn’t a by-law like that, allowing children to do that when it is so obviously dangerous is just plain stupid and opens the owners up to personal liability.