EMPIRICAL EVALUATION OF PEAK GROUND ACCELERATION (PGA) AND SEISMIC ZONATION IN NORTH MALUKU

Abstract

North Maluku, a region characterized by significant seismic activity, frequently experiences earthquakes that result in various effects, including ground motion. This study evaluates the Peak Ground Acceleration (PGA) values and maps its distribution zones in the North Maluku region using three empirical Ground Motion Prediction Equations (GMPEs): Donovan, McGuire, and Esteva. This research uses a catalog of earthquakes with magnitudes ≥5 and depths <70 km, which occurred in the region between 2010 and 2025. The earthquake data were converted to surface magnitudes and then processed to obtain Peak Ground Acceleration (PGA) values for the three models. The results of each model were then mapped. The results indicate that the Donovan method yields a PGA range of 0.0168g–0.0690g, the McGuire method provides a higher range of 0.0225g–0.0905g, while the Esteva method presents a lower range of 0.0014g–0.0107g. All models consistently identify high-risk zones along the eastern and northern coasts of Halmahera. These variations reflect differences in attenuation behavior, probabilistic assumptions, and depth sensitivity. This demonstrates that spatial consistency across multiple empirical models provides a more reliable and robust basis for seismic hazard zonation than reliance on a single model. The findings highlight the importance of multi-model integration for improving seismic hazard assessment and support the development of more resilient infrastructure and disaster mitigation strategies in seismically active regions.