Adequate and timely seismic hazard assessment in an earthquake-prone country like the Philippines is essential. Earthquakes in South Cotabato have underlined the phenomenological influence of local geological conditions on levels of damage and the resultant loss of life. The advancement of suitable earthquake-resistant structures through reliable ground motion prediction utilizing seismic provision and site-specific investigation can reduce life losses and damages from a devastating earthquake. This study developed a site-specific response spectrum in the Municipality of South Cotabato using a Probabilistic Seismic Hazard Analysis approach. The R-CRISIS, Z-Map, and ArcGIS are the tools used to generate the result utilizing earthquake catalog from DOST-PHIVOLS and USGS as inputs in the model. The work revealed that t=0.01s, Municipalities of Banga, Koronal City, Lake Sebu, Norala, Santo Niño, Surallah, and Tantangan transcend the value of spectral acceleration using at t= 0.00 s of NSCP response spectrum of 0.4g by 0.466g, 0.451g, 0.437g, 0.492g, 0.48g, 0.44g, and 0.489g respectively. On the other hand, General Santos City, Polomolok, T’Boli, Tampakan, and Tupi is a lesser value than of NSCP response spectrum at t=0.01s by 0.34g, 0.316g, 0.379g, 0.383g, and 0.340g, respectively. The response spectrum developed from the PSHA generally provides a better response spectrum for site response analysis. The study’s result is a useful reference to the structural engineer or any project implementing agency to establish infrastructure in South Cotabato Region. Furthermore, the results maximized as a basis for the future development of structural engineering in the Province and the first step toward developing site-specific spectral shapes for earthquake engineering applications in the Philippines.

Seismic Hazard Analysis, PSHA, site-specific response spectrum, R-CRISIS, ZMAP