Dear sdz,
Trying to help you here.
AFAIK, Indonesia is divided to 6 seismic zone, which
very much different from API 650, from highest to lowest:
Zone 1: basic seismic coeff. for firm ground = 0.13
Zone 2: basic seismic coeff. for firm ground = 0.09
Zone 3: basic seismic coeff. for firm...