Why is it called the donut effect in geography?

Answer 1

It is called the donut effect because the city centre becomes 'hollow' with the wealthier, affluent residents living on the urban fringe due largely to surburbanisation whilst the inner city contains the working class people and is an area of physical decay, economic decline, increased crime and vandalism. The doughnut effect can be observed in many American cities, in particular Los Angeles where the city centre is a 'ghetto'. Australia is also beginning to experience this phenomenon in some cities like Brisbane and Sydney - however, not as extreme as in America.