The 2D Finite Difference Numerical Modelling of P-SV Wave Propagation In Elastic Heterogeneous Medium Using Graphic Processing Unit: Case Study of Mount Merapi Topography, Yogyakarta

Simulation of seismic wave propagation has been very important way to study the relation between a specific condition of earth medium and seismogram recorded during a seismic event such as an earthquake. In this study, a numerical modelling of P-SV wave propagation in elastic heterogeneous medium has been done using fourth order finite-difference method. The medium model was created based on topography profile of selected line intersecting Mount Merapi, where 200 meters thick low-velocity layer has been added. The computation was performed using an NVIDIA CUDA-enabled graphics card. Synthetic seismogram was recorded at three receiver stations and was obtained by using a deep seismic source and a shallow seismic source located within the volcano. Results shows significant differences of wave propagation in presence of topography and low-velocity layer, while compared to the homogeneous version of the model which excludes the low-velocity layer. The formation of surface wave is also proved to significantly affect the recorded seismogram. Topography, low-velocity layer located at near-surface, and generated surface wave are suspected to be responsible for the complexity of the recorded seismogram. Compared to computation by using only CPU, usage of NVIDIA graphics processing unit proved to be successful to accelerate the execution time by 23 times.