PEMETAAN DAERAH RAWAN REKAHAN TANAH BERDASARKAN ANALISIS MIKROTREMOR DI KOTAMADYA DENPASAR DAN KABUPATEN BADUNG, BALI; MAPPING THE FISSURE VULNERABLE ZONES BASED ON MICROTREMOR ANALYSIS IN DENPASAR MANUCIPALITY AND BADUNG REGION, BALI

Prabowo, Urip N, Sismanto

2015 | Disertasi | FMIPA

Denpasar Manucipality and Badung Regency as the areas with excessive ground water exploitation and high earthquake intensity. This condition will cause these area are vulnerable with land subsidence which is triggering ground fissures when land subsidence occours in the area which have different bedrock height. This research was done to mapping the fissure vunerable area due to escessive ground water exploitation and earthquake using single station mictrotremor measurements which was analyzed using HVSR method and array microtremor measurements which was analyzed using spatial autocorrelation (SPAC) method. The result of HVSR method and peak ground acceleration (PGA) value were analyzed to obtained ground shear strain value. The result of this research concluded that quality factor has linier relations with amplification and dominant frequency values. Based on the maps was made in this research, the area has seismic vunerability index value about 1,00-7,39, ground shear strain value about 27,38x10-6-1753,90x10-6 and bedrock formed basin structure at south of the area. The fissure vulnerable area due to the excessive ground water exploitation is west Denpasar subdistrict. In addition, based on the basement map and ground shear strain value which were combined using simple additive weight (SAW) method, there are two fissure vulnerable areas due to eathquake, i.e west and south Denpasar subdistrict.

Kata Kunci : Fissures; Microtremor; HVSR; SPAC; Ground Shear Strain.