soil settling

hi i just had a ton of soil delivered which filled 3/4 of my dog run , i levelled it of where possiable but question is will it sink as i think i only need 1/2 ton to finish or should i order a ton to topup where it settles .
the area i filled is about 8cm deep and not been trodden down as i want to seed it with grass cheers j

 

It will settle naturally over time but if you are going to seed it will need treading firm several times between rakings .
You will need to allow a good while after seeding to establish before it is suitable for the dog to run on ..
Dave