Source Parameterization of Finite Faults in Earthquake Ground Motion Simulation

The effect of interpolation function for describing spatial variations of slip on the fault surface is investigated using finite fault simulation. In analogy with h-p notion in finite element method, the effect of increasing the order of interpolation function and decreasing the size of elements is studied here. In this regard, the fault surface is discretized using different elements, namely, constant discontinuous elements with various sizes, and first order contentious elements with different sizes. In order of parameterization, a bilinear interpolation technique is introduced to represent variation of source parameters within the subfault area. To provide an objective basis for comparison, the September 28, 2004 Parkfield earthquake Mw 6.1 is considered and time-frequency, envelope-phase goodness-of-fit criteria is calculated to compare synthetic and observed waveforms quantitatively in time and frequency domains. It was revealed that by increasing the order of interpolation function, the overall consistency of observed and synthetic waveforms will increase, while the expense of computational analyses will also increase accordingly.