According to David Blanchflower and Andrew Oswald (1994, p. 5), the wage curve summarizes the fact that "A worker who is employed in an area of high unemployment earns less than an identical individual who works in a region with low joblessness."
However, depending on the labour market conditions, other options are open: Say that there are not very many jobs in the labour market, unemployment is high and a lot of people are under-employed (working much fewer than X hours).
It is very hard to find people who are not already earning $A an hour, and because of that you must match the money offer elsewhere in order to get someone to work for you.
One of the reasons why unemployed labourers would not want to migrate to other areas with plenty of jobs is because of home-ownership.
However recently some micro econometric evidence suggests that the relationship between home-ownership and unemployment is slightly more complicated.
The overall picture suggests that although home-owners are reluctant to move around, they are more often than not employed, and therefore not contributing to the unemployment rate.