SIMULASI NUMERIK UNTUK ANALISIS KURVA DISPERSI DARI PENJALARAN GELOMBANG PERMUKAAN MENGGUNAKAN METODE FINITE DIFFERENCE PADA MEDIUM ELASTIK; NUMERICAL SIMULATION FOR DISPERSION CURVE ANALYSIS OF SURFACE WAVE PROPAGATION USING FINITE DIFFERENCE METHOD IN ELASTIC MEDIUM

Winata, Ekrar, Eddy Hartantyo

2015 | Skripsi | FMIPA

Numerical simulation of surface wave propagation has been made using finite difference staggered-grid method in MATLAB. This program has been verified by comparison between numerical of dispersion curve and the theoretical curve that obtained by calculation of two layer medium using Rix and Lai’s algorithm. This comparison shows the suitability between fundamental-mode of Rayleigh wave. This program is used to create a wave propagation using three models: three layers model, stepping-up model, and low velocity layer model to get the snapshot result and synthetic seismic data. Resulting dispersion curves show match in the high frequency range for three layers model with the theoretical of dispersion curves. The stepping-up model is used to explore the interaction source position with the near surface structure. When elastic waves interact with the near surface structure, diffraction process occurs at the location of the near surface structure. The near surface structure is suspected to be responsible for the complexity of the recorded seismogram. Then, dispersion curve image is extracted from the recorded seismogram which can enhance the structure’s signature. And low velocity layer model illustrates high-low velocity interface. The observed of dispersion curves allows the prediction of change in the dispersion curves shape under the influence of velocity’s medium.

Kata Kunci : Elastic medium; numerical simulation; staggered-grid method