SEISMIC VULNERABILITY ESTIMATION BASED ON ANALYSIS HORIZONTAL-TO-VERTICAL SPECTRAL RATIO (HVSR) FROM MICROTREMOR DATA IN TASIKMALAYA CITY

• Main Author: Nicolash, Edward
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/52101
• Institution: Institut Teknologi Bandung

On 15 December 2017 earthquake occur with epicenter at Tasikmalaya District generate magnitude 6,9. The result of the earthquake, Tasikmalaya suffered damage thousands of buildings and two casualities. Production map of disaster zone in Tasikmalaya is necessary to support mitigation. On geologically aspect Tasikmalaya formed by alluvium and volano product which make this surface structure weakly consolidated. That factor made increasing amplification wave energy while earthquake. Microtremor observation can be used for analysis vulnerability seismic in Tasikmalaya. Horizontal to Vertical Spectral Ratio (HSVR) applied to analysis HVSR curve with variation frequency from microtremor data. Obtained predominant frequency ranged from 1,23 to 6,12 Hz and amplification value ranged from 2,3 to 5,51. Low predominant frequency and high amplification value in several area indicated increase ground shake while earthquake occur. Neighborhood Algorithm applied during inversion HVSR curve to determined velocity shear wave (Vs). Obtained velocity shear wave ranged from 315 – 3000 m/s. The value velocity shear wave increases equal with increasing depth. Average velocity shear wave 30 meter (????????30) mapped to determine classification soil. Obtained distribution ???? ???? 30 value ranged from 350 – 750 m/s. With that result from classification SNI 1726:2012 Tasikmalaya classified by hard soil (SC). From this research obtained area in Tasikmalaya which vulnerability during earthquake is East Purbaratu, East Cibereum, NorthEast Kawalu, and North-West Tamansari