STUDY OF POROSITY IN RELATION WITH THE SHEAR HORIZONTAL WAVE (SH-WAVE) VELOCITY (CASE STUDY: BANTUL REGENCY AREA, YOGYAKARTA)

• Main Author: (NIM : 22106318), WIYONO
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/20620
• Institution: Institut Teknologi Bandung

Rock porosity determination is point of interest in the field of hydrogeology to know characteristic the rock and fluid. Currently, determination the rock porosity <br /> <br /> is conducted by sampling and laboratory test. Relationships porosity with Shear-horizontal seismic wave velocity (SH-wave) was conducted using seismic reflection method in Bantul regency area, Yogyakarta Special Province. The Shear wave seismic has several advantages comparing with Primary wave seismic because the Shear wave seismic has shorter wavelength than the Primary wave, in consequence the Shear wave seismic has better vertical resolution than Primary wave. Seismic data processing was correlated with sample soil core from 40 boreholes data in Bantul regency area. Porosity estimation result from Shear wave velocity was validated with the porosity value from the laboratory test result. <br /> <br /> Borehole data show that the lithology of study area is dominated by the sand with clay and silt intercalation. Groundwater elevation at study area is 0.3 m to 4 m in <br /> <br /> depth from the ground level. The regional groundwater direction flow is northeast - southwest. The porosity value estimation from Shear wave seismic velocity show similar value with laboratory porosity test data. The porosity value estimation from 26 m to 40 m in depth from the ground level shows that the porosity decreases due to the rock compaction.