Indicator-Based Assessment of Seismic Vulnerability Factors in Spanish Colonial Heritage Churches in Bohol, Philippines

Reymarvelos Oros; Joel Opon

doi:10.52751/cmujs.2025.v29.i2.y4r2qq65

Authors

Reymarvelos Oros MSU-Iligan Institute of Technology Author
Joel Opon MSU-Iligan Institute of Technology Author

DOI:

https://doi.org/10.52751/cmujs.2025.v29.i2.y4r2qq65

Keywords:

seismic vulnerability, heritage churches, unreinforced masonry, indicator-based assessment, cultural heritage conservation

Abstract

This study evaluates the seismic vulnerability of three 19th-century Spanish colonial heritage churches in Bohol, Philippines—Santa Monica (Alburquerque), San Nicolas de Tolentino (Dimiao), and San Agustin (Panglao)—which serve as notable examples of unreinforced masonry construction that endured the 2013 Bohol earthquake. A proxy indicator-based approach was employed to quantify key parameters influencing seismic behavior, including wall slenderness, plan regularity, buttress adequacy, and belltower rigidity. Statistical analyses, such as mean, standard deviation, and coefficient of variation, were used to examine variability among indicators and identify those contributing most to seismic susceptibility. The results demonstrate the applicability of indicator-based methods for assessing heritage structures where detailed geometric and material data are unavailable. Differences in wall proportions, connections, and architectural configurations reveal variations in historical construction practices and their implications for lateral load resistance. This indicator-based approach offers an efficient means of characterizing the seismic vulnerability of unreinforced masonry heritage buildings using measurable parameters. Overall, the findings provide a methodological basis for informed heritage conservation, risk reduction, and structural assessment, contributing to a broader understanding of how architectural form and construction typology affect the seismic resilience of Spanish colonial churches in the Philippines.

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