One has to be careful to distinguish revivals from revivalism. The difference between the words is a theological difference. The former can be described as Calvinistic preaching being blessed of God when no humanistic theological means are employed; the latter is usually a case of Arminian or pelagian preaching achieving an effect that can be directly linked to human effort and orgainization. In the US, when mass movements occured they were mostly revivals up till the time of Nettleton. After Nettleton, revivalism arrived with C. G. Finney and his spiritual decendents down to Billy Graham today. The tragedy is that many Reformed folk who have rightly rejected revivalism tar revivals with the same brush.
For further information see Ian Murray, "Revival and Revivalism" published by the Banner of Truth Trust.

In Christ's love and service
Timmopussycat