Brining

Brine Curing 

To begin, brine is by definition a mixture of water and salt.
Method: To begin the curing process, the olives are soaked in brine, (which you've made), for approximately 30-40 days. During this time period, it is important to put the olives in fresh brine solution because they begin to ferment in it over time.
Taste/Flavor: Brined olives have a sour taste because while they ferment in the brine, they produce a lactic acid that gives them this flavor.
Region: Throughout my research I've seen brining labeled as the Sicilian treatment, so it is plausible, that this particular process is prominant in Sicily.

Sources: Click on the title for further information.