Development of new seismic hazard maps of the Philippines using the neo-deterministic seismic hazard assessment approach

Abstract

The geographical positioning of the Philippines has rendered it susceptible to devastating earthquakes, resulting in significant human and economic losses throughout its history. Given the persistent earthquake risk, there is a need to explore all available methodologies to comprehensively portray the seismic hazard profile of the country and to supplement the current Philippine Earthquake Model (PEM). Moreover, the probabilistic seismic hazard assessment (PSHA), the method employed in PEM, has faced several critiques in scholarly discourse. As such, this study employed a relatively new approach, the neo-deterministic seismic hazard assessment (NDSHA) which addresses many of the limitations associated with PSHA, to the Philippines to develop new seismic hazard maps of the country. NDSHA offers the capability to simulate ground motion parameters at bedrock levels by leveraging insights into the physical mechanisms of earthquake generation and wave propagation in a realistic medium. The application of NDSHA yielded six distinct seismic hazard maps of the Philippines containing information on calculated Peak Ground Displacement (PGD), Peak Ground Velocity (PGV), and Design Ground Acceleration (DGA). These resultant maps, which have been statistically corroborated with empirical earthquake records, identified five specific areas in the country with heightened seismic hazards. This implementation of the regional-scale NDSHA method provided new insights into the seismic hazard landscape of the Philippines, thereby enriching the reservoir of information available for infrastructure seismic assessment, analysis, and design endeavors.