FREQUENCY, ANISOTROPY ORIENTATION, AND PRESSURE EFFECTS ANALYSIS OF SHEAR WAVE SPLITTING IN CALCITERESIN SPECIMEN

• Main Author: DARIANTO, ANTONIUS
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/25701
• Institution: Institut Teknologi Bandung

Shear waves is an effective tool to detect subsurface structures because s-wave is polarized to <br /> <br /> many directions and can carry information regarding the orientation of distributed fractures <br /> <br /> along its ray path. Polarized shear wave is the dominant cause of Shear Wave Splitting <br /> <br /> (SWS). SWS is a phenomenon that occurs when a polarized shear wave enters an anisotropic <br /> <br /> medium. In the simplest case of shear waves propagating in an isotropic medium, the waves <br /> <br /> are split into SV-wave that is polarized in the plane of propagation and SH-wave that is <br /> <br /> polarized orthogonal to it. In this final project, calcite-resin specimen is used to identify the <br /> <br /> behavior of wave, especially polarized s-wave, in a variety of frequencies and pressures. <br /> <br /> Specimen takes form in a tubular shape with 4,6 cm diameter and 6 cm length. In each <br /> <br /> specimen, various angle of calcite’s placement is applied in hope to reveal the difference of <br /> <br /> anisotropy parameters. Frequencies of the source used in this experiment are 100kHz, <br /> <br /> 200kHz, 500kHz which are transmitted from Sonic Viewer - SX 5251C and 1000 kHz from <br /> <br /> Panametric 5072PR. Meanwhile, the compressor used in this experiment to generate a stable <br /> <br /> and controlled pressure condition is TENSILON RTF-1310 Digital Compressor, with <br /> <br /> variance of one kN and two kN pressure. Wave velocities from each condition will be <br /> <br /> compared one to another in order to discover the characteristic of the wave’s behavior <br /> <br /> towards the specimen. From previous studies, the difference on velocity-to-frequency ratios <br /> <br /> shows a similar pattern and the difference on source frequency will determine the extent of <br /> <br /> the apparent Shear Wave Splitting. In this case, low frequency give better results than <br /> <br /> measurement in high frequency. Wave velocity is also greater proportional to the amount of <br /> <br /> pressure given and the approching angle of anisotropy to the wave propagation angle.