PEMODELAN BAWAH PERMUKAAN GUNUNG LUMPUR BLEDUG KUWU, GROBOGAN, JAWA TENGAH BERDASARKAN INVERSI DATA MIKROTREMOR; SUBSURFACE MODELING MUD VOLCANO BLEDUG KUWU, GROBOGAN, CENTRAL JAVA BASED ON INVERSION OF MICROTREMOR DATA

Saka, Bergita G M, Wiwit Suryanto

2015 | Disertasi | FMIPA

Subsurface modeling of Bledug Kuwu mud volcano records has been carried out based on the microtremor data using three componens single station measurement. The aim of this modeling is to determine the depth of Bledug Kuwu mud volcano bedrock. Data processed by inversion of HVSR (Horizontal to Vertical Spectral Ratio) spectra to acquire the dominant frequency and ground amplification. HVSR Inversion performed by Monte Carlo methods based on random value with of six initial parameters are primary wave velocity (VP), secondary wave velocity (VS), density of the rock (?), thickness (h), primary quality factor (QP) and scondary quality factor (QS). The inversion results is the shearwave velocity profile as a function of depth. Three dimentional Vs image of Bledug Kuwu subsurface show rising mud track the sediment layer is at a depth of 300 meters are estimated come from the southwest with lowest secondary wave velocity 40 m/s. secondary wave velocity is ranged more or less (100 - 600) m/s is a sedimentary mud, clay and sand included in this type of loose material (alluvial). Bledug Kuwu bedrock layer composed of a material which is shale and secondary wave velocity be more than 500 m/s

Kata Kunci : Mud volcano; Subsurface modeling; HVSR (Horizontal to Vertical Spectral Ratio); Inversion.