Year: 2026 | Month: May | Volume: 13 | Issue: 5 | Pages: 806-813
DOI: https://doi.org/10.52403/ijrr.20260581
Microtremor HVSR Analysis for Land Movement Identification in Pandanmurti Field, Sumowono District, Semarang Regency, Indonesia
M Irham Nurwidyanto1, Gatot Yuliyanto2
1Department of Physics, Faculty of Science and Mathematics, Diponegoro University, Semarang, Indonesia.
2Department of Physics, Faculty of Science and Mathematics, Diponegoro University, Semarang, Indonesia
Corresponding Author: M Irham Nurwidyanto
ABSTRACT
Local site effects significantly influence seismic wave amplification and slope instability in volcanic terrains characterized by weathered deposits and high rainfall intensity. This study applies the Horizontal-to-Vertical Spectral Ratio (HVSR) microtremor method to characterize local site effects and evaluate seismic vulnerability in Pandanmurti Field, Candigaron Village, Sumowono District, Central Java, Indonesia. The area experienced severe land deformation in 2017, resulting in extensive ground cracking, subsidence, and structural damage. Twenty ambient vibration measurements were recorded using a three-component seismometer and processed using Geopsy software following SESAME guidelines. HVSR analysis was performed to determine dominant frequency (f0), amplification factor (A0), seismic vulnerability index (Kg), peak ground acceleration (PGA), and ground shear strain (GSS). The results indicate dominant frequency values ranging from 0.03 to 0.12 Hz and amplification values between 4.3 and 6.7. Low dominant frequencies indicate thick unconsolidated weathered deposits, while high amplification values indicate strong impedance contrast between soft surface materials and compact subsurface layers. Seismic vulnerability index values range from 0.0008263 to 0.0265714 cm/s, whereas PGA values range from 10.09 to 46.76 gal. High seismic vulnerability zones spatially correlate with observed deformation areas and elevated ground shear strain values. The integrated interpretation demonstrates that areas characterized by low dominant frequency and high amplification exhibit higher instability potential. The study confirms that HVSR microtremor analysis is an effective and economical approach for identifying unstable site conditions and supporting disaster mitigation strategies in landslide-prone volcanic environments.
Keywords: Microtremor, HVSR, land movement, seismic vulnerability index, ground shear strain
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