50%+ of players must vote for a single individual to lynch them...
With 15 alive, it takes 8 votes to lynch a player means that a single player needs to receive 8 votes to be lynched. The exception being if the 72 hour deadline is reached without a lynch...then the high vote-getter is lynched.
As an addition here (but already covered in the rules above):
1. Once a player has received a hammering vote, they're dead. Unvoting will not undo the lynch.
2. Any mafia hits sent in BEFORE the occurrence of a hammering vote will take priority...even if I do not read and act on the hit until after the hammer has occurred in the thread. This has the potential of undoing what what might seem to be a lynch.