Seismic Vulnerabilities Disaggregation Chart in the 2^nd District of Cagayan de Oro City, Philippines

University of Science and Technology of Southern Philippines, Cagayan de Oro City, Philippines

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Abstract

This study demonstrates the development of a site-specific response spectrum for the 2^nd District of Cagayan de Oro City, Philippines, utilizing the R-CRISIS seismic hazard analysis software. The response spectrum was generated using a short vibration period of 0.01 second, a design life of 50 years, and an epsilon value of 5, representing an uncommon seismic event with high ground motion levels. The analysis incorporated local geological and seismotectonic parameters to reflect the unique seismic hazard conditions of the area. Through the use of R-CRISIS, exceedance rates of ground motion were computed and disaggregated by earthquake magnitude, source-to-site distance, and epsilon. The disaggregation charts revealed the dominant earthquake scenarios contributing to the hazard at the designated period and location. The results show that Lapasan, Nazareth, Consolacion, Macabalan, Puntod, and Barangay 1-40 are most vulnerable to earthquake hazard; Cugman, Indahag, Camaman-an, Gusa, and Macasandig are highly vulnerable to earthquake hazard; Balubal, Bugo, Puerto, and FS Catanico are moderately vulnerable to earthquake hazard; and Agusan and Tablon are least vulnerable to earthquake hazard. Additionally, vulnerability charts were generated to visualize ground tremor intensity and hazard levels across the study area. These charts serve as critical instruments for identifying high-risk zones and guiding local land use planning, infrastructure design, and disaster preparedness strategies. This work contributes to the ongoing efforts of seismic risk reduction in the region by providing localized, science-based hazard information tailored for engineering and planning applications.