Velocity Dispersion Analysis of Shallow Crustal Structures North of Bukit Bunuh, Lenggong, Perak

In the Earth there is no such perfectly elastic medium. In an elastic medium, wave particles that travel through the medium could be distorted due to velocity dispersion and attenuation. Velocity dispersion is highly depends on several factors. The factors could be: porosity, fractures, fluid mobility and also the scale of heterogeneities. In 2012, number of core samples was taken from Bukit Bunuh, Lenggong, Perak to measure the velocity P-waves and S-waves of the cores in the laboratory. One seismic reflection line was acquired in the outcrop back in May 2014. From the previous final year project shows ‘hockey-stick’ effect once applied the specific velocity ranges obtained in the laboratory for granite in velocity analysis for deep area. A series of experiments will be conducted to determine the velocity variation of granite formation at West of Bukit Bunuh over as wide a frequency range as possible. This project will cover two aspects; the geological structure of Bukit Bunuh as well as the geophysical aspect whereby seismic data processing is the main focus in this project. The experiments that will be conducted fall into two categories: (1) Reflection survey measurement (10-250Hz) with dominant frequency of. 35Hz and (2) Laboratory measurement (300-900kHz) with dominant frequency of 700kHz. Difference ranges of frequencies applied in both field and laboratory measurement are the main reason for velocity dispersion. Further analysis of the velocity dispersion will show that the laboratory velocity measurement cannot be directly applied to the reflection seismic data during the velocity picking since both experiment were acquired by using different frequency range. The application of the velocity obtained in laboratory to the reflection data will show the hockey-stick effect instead of flattening the layers in gathers