ANALYSIS OF MICROTREMOR H/V SPECTRAL RATIO AND PUBLIC PERCEPTION FOR DISASTER MITIGATION

Abstract

The NW–SE-striking Seulimeum fault in northernmost Sumatra has triggered several major earthquakes in the last decades and can thus harm the surrounding community. The microtremor HVSR method was implemented in the Lamteuba area, which is proximate to the Seulimeum fault, to analyze the possible seismic impact of numerous shallow-depth earthquakes. HVSR values were calculated for 21 sampling points. Results show that the dominant frequency is between 1 and 4 Hz, and the dominant period is 0–0.5 s; these are associated with young volcanic sediment. The areas with the highest amplification are located in the central and southern parts of the study area, with a vulnerability value (Kg) greater than 1. The Kg value of the northern part is under 1 because of its proximity to a Tertiary volcanic rock formation. About 40% of the study area is vulnerable to earthquakes, as suggested by the high susceptibility index, which is associated with soft sediment. These results are supported by the perception of the local community, which serves as a framework for acculturating the mitigation. The public perception responses show a lack of the knowledge and infrastructure needed to mitigate disasters in the area. This study also reveals a lack of actions to be taken before, during, and after a disaster. This work successfully combines seismic analysis with public perception to determine the earthquake risk level and develop a mitigation plan for the study area.