PEMETAAN DAERAH RAWAN RESIKO GEMPABUMI BERDASARKAN METODE PROBABILISTIC SEISMIC HAZARD ANALYSIS (PSHA) DAN ANALISIS DATA MIKROTREMOR DI KOTAMADYA DENPASAR DAN SEKITARNYA, BALI
KURNIAWAN, RISKI, Sismanto
2016 | Disertasi | FMIPAMapping seismic hazard has been done by using Probabilistic Seismic Hazard Analysis (PSHA) and microtremor analysis at Denpasar City and its surrounding. This research aims to map risk areas in the research area based on the PSHA results using software Ez-Frisk 7.52 and the results of microtremor data single station on 249 measuring points that were processed using software geopshy. The result of calculation PSHA value from all sources of the earthquake in Bali island has showed with PGA (Peak Ground Acceleration) (T = 0.0 second) for return period 500 and 2500 years has range between 0.2 g – 0.35 g and 0.4 g – 0.6 g. While the result based on hazard map in bed rock with spectra condition T = 0.2 second in return period 500 and 2500 years obtained the value 0.5g - 0.8 g and 0.9 g – 1.3 g. Based on hazard map in bed rock with spectra condition T = 1.0 second in return period 500 and 2500 years obtained the value 0.15 g – 0.3 g and 0.25 g – 0.45 g. The result from processing microtremor shows that denpasar city have a local geology characteristic with dominant frequency range between (0.96 - 14.59) hz, amplification value between 1.15 – 12.08, index seismic susceptibility value between 0.27 – 39.81, the value of ground vibration acceleration (34.93 – 147.59) and the value of ground shear strain 1.5 x 10?5 – 2.1x 10?3 Based on the value from PSHA analysis shows that Bali Island is an earthquake vulnearble area where has variation value based on characteristic of each earthquake source. Especially for the Denpasar city and surrounding, based on processing mikrotremor shows the southern part research area have a potential disaster rather than northern area.
Kata Kunci : Bali Island, Denpasar city, PSHA, microtremor.
