Theoretical Study on the Flow Generated by the Strike-Slip Faulting

The flow driven by the strike-slip faulting is theoretically analyzed in this paper. The surface of the strike-slip fault is generally near vertical, and the corresponding plates move in horizontal directions during the faulting. The focus of present paper is on the flow at the early stage when the faulting is activated. Standard procedures for deriving the exact solution of the induced flow are first demonstrated. Based on the derived solution, flows generated by three kinds of faulting are examined to observe and compare the evolution of velocity profiles and the corresponding kinetic energy. The results show that the flow energy rapidly decays as the speed of the moving plates begins to slow down. Moreover, mathematical methods proposed in this study provide a useful basis for related studies on not only geophysics, but also fluid mechanics, industry manufacturing, heat-conduction problems, and other possible applications. 1. Introduction It is well known that many earthquakes are attributed to the fault motion. In general, there are two kinds of faults, the dip-strike and the slip-strike faults, which indicate that the relative movements on the fault plane are approximately vertical and horizontal, respectively. For oceanographers and ocean engineers, a great deal of attention is focused on not only the faulting properties but also the induced flow above the plates. From the viewpoint of energy, the dip-strike and slip-strike faults, respectively, result in the transfer of potential energy and kinetic energy from the moving plates to the fluid. As the dip-strike faulting usually transfers a considerable amount of potential energy into the above fluid, a tsunami wave is simultaneously generated on the ocean surface. Due to the catastrophic damage by the tsunami wave, related studies either on the generation or the propagation of tsunamis are quite abundant (see Ben-Menahem and Rosenman [1], Hammack [2], Okada [3], Dutykh and Dias [4, 5], and Saito and Furumura [6] for details). However, for the flow induced by the slip-strike faulting, it seems to receive much less attention from scientists. For the sake of modeling the flow driven by the strike-slip faulting, Zeng and Weinbaum [7] may be the first who theoretically studied the flow induced by relatively moving half plates. The two half plates are assumed to move either in a constant speed or a harmonic oscillation. The steady-state solution to flow velocity is then obtained by employing some mathematical techniques. However, the steady-state solution cannot exactly capture the flow at the early