Accelerating Three-dimensional Curved Grid Finite-difference Modelling For Non-planar Rupture Dynamics Using Gpu Graphics Card

In the study of seismic dynamics,the faults of actual earthquakes often have not only complex surface topographical environments,but also the shape distribution of the faults.There is no effective analytical solution,so most researchs have been carried out in numerical simulation.The three-dimensional non-planar fault rupture simulation adopts the curve finite difference method,which can simulate the complex terrain-surface,the slope and the fault rupture process with irregular geometry,and broaden the model that the finite difference method can be applied.However,while inheriting the advantages of high precision and intuition of the finite difference method,it also has the disadvantage that the finite difference method is computationally intensive and requires high computational resources.With the failure of Moore's Law,the performance of CPU(Central Process Unit)updates is slowing down,at the same time,the GPU(Graphics Process Unit)is rapidly developing driving by the game market.Image processing requires massive parallel computing to meet this need,so GPU is designed as a massively parallel computing architecture in hardware design.In recent years,the CUDA programming model developed by NVIDIA has facilitated the porting of general-purpose computing programs to GPU devices.Using GPU parallel processing to speed up computing tasks,shorten computing time,and quickly achieve large-scale application in the academic and industry.This paper introduces the GPU heterogeneous programming and CUDA parallel programming model,and introduces the theoretical basis of the three-dimensional curve finite difference method in describing the spontaneous rupture process of faults,under seismic wave field propagation and sliding weakening criteria.Combined with the CUDA parallel programming model for programming,implemented the finite difference program of the three-dimensional non-planar fault rupture simulation,that is,the seismic wave field propagation under the curve coordinates,the spontaneous fault of the seismic fault is used as the boundary condition and wave field in the wave field.The coupling,traction image method achieves surface free surface simulation,and CPML boundary conditions.Finally,the simulation results of the multi-core MPI program of the GPU program and the three-dimensional non-planar fault rupture numerical simulation in the whole space uniform medium plane fault and the free surface tending fault are compared,and both of them have good accuracy within the precision range.Consistency.The generality of the complex fault simulation should be verified by simulating the rough fault of the free surface with the GPU program.On the basis of ensuring accuracy and universality,the acceleration effect of GPU versus CPU using single-precision floating-point simulation is compared,which is around 413.6/181.7/76.6/30.7 speedup respectively compared with1/4/12/24 processor(s).As of now,this study is the first implementation of numerical simulation using GPU to accelerate 3D non-planar fault rupture.