Leans of walls are a symptom of earthquake damage.  This is know as wall verticality.  We recently did a trial against Lumley General Insurance  where the primary issues was whether the wall leans were caused by earthquake(s) and if so, what is the required remedial work and cost.  The Court reserved its decision.  The lean of walls is often an item overlooked by people assessing earthquake damage.  It is important that it is not overlooked.