Desi Mustami Limayukha Desi Mustami Limayukha, Mochamad Aryono Adhi Adhi, Nugroho Budi Wibowo, Billqis El Farsiyyi Bilqis El Farsiyyi, Elsa Fadlika Widyantari Elsa Fadlika Widyantari, Ilqia Rahma Ilqia Rahma, Rahmania Sofyana Ulya Rahmania Sofyana Ulya

Seismic Vulnerability Microzonation Based on Dominant Frequency and Amplification Using the HVSR Method in Wedi, Changewaro (Klaten) and Gendangsari (Yogyakarta)

Introduction

Seismic vulnerability microzonation based on dominant frequency and amplification using the hvsr method in wedi, changewaro (klaten) and gendangsari (yogyakarta). Assess seismic vulnerability microzonation in Klaten & Yogyakarta using HVSR. Analyze dominant frequency, amplification, and soil types to map earthquake risk and moderate damage potential.

Abstract

The Yogyakarta region is prone to frequent earthquakes, highlighting the need for seismic vulnerability assessment and micro zonation analysis. This study aimed to evaluate the area's seismic vulnerability by utilizing microtremor methods to estimate dominant frequency, amplification, seismic vulnerability index, and shear wave velocity. Microtremor points were analyzed using the Horizontal Vertical Spectral Ratio method, with data processed through Geopsy software to obtain f0, A0, and H/V curves. The H/V curve was further inverted using Dinver software to derive ellipticity curves, ground profiles, and Kg values. The results revealed that the dominant frequency values ranged from 0.668 Hz to 18.271 Hz, with higher values prevalent. The soil types in the area were classified as type IV and type I, primarily consisting of older, hard sandy rocks and gravels. Amplification values ranged from 1.03 to 8.36, indicating low amplification levels and placing the area in zone 1. Kg values varied from 0.066 to 15.07 s²/cm, suggesting moderate seismic vulnerability. If an earthquake occurs, the region would experience shaking, though damage would be moderate. Vs30 values ranged from 179.64 m/s to 681.82 m/s, categorizing the soil as hard, dense, soft, or medium.

Review

This study effectively addresses a critical need for seismic vulnerability assessment in the earthquake-prone Yogyakarta region. By employing the microtremor-based Horizontal Vertical Spectral Ratio (HVSR) method, the authors aimed to characterize the subsurface in Wedi, Changewaro, and Gendangsari, providing essential parameters such as dominant frequency (f0), amplification (A0), seismic vulnerability index (Kg), and shear wave velocity (Vs30). The findings indicate a wide range of dominant frequencies (0.668 Hz to 18.271 Hz) and amplification values (1.03 to 8.36), leading to the classification of the area into low amplification Zone 1. Critically, the study concludes that despite potential shaking, the region exhibits moderate seismic vulnerability, supported by Kg values between 0.066 and 15.07 s²/cm and Vs30 values suggesting a mix of hard, dense, soft, or medium soils. A significant strength of this research lies in its robust methodological approach, utilizing established techniques for seismic site characterization. The use of specialized software like Geopsy for HVSR curve generation and Dinver for inversion to derive detailed ground profiles and Kg values demonstrates a commitment to thorough data processing and interpretation. The multi-parameter estimation (f0, A0, Kg, Vs30) provides a comprehensive understanding of the subsurface conditions and their implications for seismic response. Furthermore, the classification of soil types and amplification zones, coupled with an overall assessment of seismic vulnerability, offers valuable baseline data for urban planning and risk management in the targeted localities. While the abstract clearly outlines the methodology and results, some aspects could benefit from further clarification in the full paper. For instance, the statement that "soil types in the area were classified as type IV and type I, primarily consisting of older, hard sandy rocks and gravels" seems to contain a slight ambiguity, as Type IV typically denotes soft soils while Type I represents hard rock; a clear reference to the specific classification system (e.g., NEHRP) would be beneficial. Additionally, a more explicit discussion on how the "low amplification levels" (Zone 1) reconcile with "moderate seismic vulnerability" would enhance the clarity of the overall risk assessment. Nevertheless, this study provides an invaluable foundation for understanding local seismic hazards, and its findings are directly applicable to improving building codes and disaster preparedness strategies in the investigated areas. Future work could benefit from detailed geological mapping correlation and a visual representation of the microzonation maps to further maximize the impact of these findings.

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