“Seismic Vulnerability Index Analysis Using the HVSR (Horizontal to Vertical Spectral Ratio) Method in Nagari Malampah, Tigo Nagari District, Pasaman Regency”. PILLAR OF PHYSICS 19, no. 1 (April 30, 2026): 89–97. Accessed May 15, 2026. https://pop.ppj.unp.ac.id/index.php/pop/article/view/31.