Amplification Analysis and Seismic Vulnerability Index of Air Tawar Barat Village of Padang City Using HVSR Method

Abstract

Padang City is an area that has a very high level of seismic activity in Indonesia. The city of Padang is also an area severely affected by the earthquake in the Subduction Zone. Considerable earthquakes impact building damage and infrastructure, one of the factors that can see the vulnerability of an area with a seismic vulnerability index. Therefore, a study was conducted to determine and analyze the amplification and seismic vulnerability index in the Air Tawar Barat Village of Padang City and create a map of the natural frequency distribution, amplification, and seismic vulnerability index. Microtremor data retrieval was carried out in February-May 2022 using the Seismograph Sysmatrack MAE and S3S Sensors at Air Tawar Barat Village, Padang City. The method used in this study is the HVSR (Horizontal to Vertical Spectral Ratio) method using geopsy software to remove noise in the data and see the natural frequency value and the value of the amplification factor. Furthermore, from the data, contour maps were made using Surfer 13, where the type of research carried out was in the form of descriptive research. Based on the results of the study found that the natural frequency value (f0) in the study area ranged from 0.59141 Hz – 12.9172 Hz, the amplification (A0) ranged from 2.39825 to 13.7759, and the seismic susceptibility index (kg) was 0.4802 – 320.885. Based on the data processing results, it can be concluded that fresh western water is an area with a high seismic vulnerability index, and the location is very vulnerable when shaken by an earthquake.