Is zakat obligatory on the association's funds, collected from members to be used for blood money (diyyat) and calamities (balaya), if a year (hawl) has passed over them?

If the reality is as you described, and what was donated does not revert to the donors in proportion to their donation, but rather their private ownership ceases upon donation, and it is spent for the purpose for which it was donated, then there is no zakat due on it.