A method for inverting 3 D curved interface and layer velocity by using travel time of reflected waves is studied. Each interface is described with sectional, incomplete cubic polynomial. A fast 3 D ray tracing meth...A method for inverting 3 D curved interface and layer velocity by using travel time of reflected waves is studied. Each interface is described with sectional, incomplete cubic polynomial. A fast 3 D ray tracing method is used in forward problem, and a least squares method with variable damping is adopted in the inverse problem. Result from numerical modelling shows that the solution can converge fast on the true model. Observational data from the Tangshan earthquake area are processed, 3 D Moho discontinuity in the area is rebuilt, and finally, the relationship between the regional structure and seismicity is revealed.展开更多
The movement of bottom high-sediment sea water under water waves,especially that of the high-sediment water layer close to the sea bottom,is important to the resuspension and settlement of sediment.Supposing that the ...The movement of bottom high-sediment sea water under water waves,especially that of the high-sediment water layer close to the sea bottom,is important to the resuspension and settlement of sediment.Supposing that the high-sediment sea water is a Newtonian fluid,based on Navier-Stokes(N-S)theory,the movement of the interfaces of air-water and water-sediment water was tracked by the volume of fluid(VOF)method.The velocity field of sediment water was simulated by considering the effect of water waves.The results show that the movement of sediment water is very different from that of sea water,which provides a solid basis for understanding the resuspension and settlement of sediment and the formation of bottom stripe,and the VOF method can trace the movement of the two interfaces simultaneously;the movement of the air-water interface has a strong effect on that of the water-sediment water interface,while the effect of the water-sediment water interface movement on the air-water interface is not obvious.展开更多
文摘A method for inverting 3 D curved interface and layer velocity by using travel time of reflected waves is studied. Each interface is described with sectional, incomplete cubic polynomial. A fast 3 D ray tracing method is used in forward problem, and a least squares method with variable damping is adopted in the inverse problem. Result from numerical modelling shows that the solution can converge fast on the true model. Observational data from the Tangshan earthquake area are processed, 3 D Moho discontinuity in the area is rebuilt, and finally, the relationship between the regional structure and seismicity is revealed.
基金The authors were grateful to the support of the Open Research Fund Program of State Key Laboratory of Water Resources and Hydropower Engineering Science(No.2005B017).
文摘The movement of bottom high-sediment sea water under water waves,especially that of the high-sediment water layer close to the sea bottom,is important to the resuspension and settlement of sediment.Supposing that the high-sediment sea water is a Newtonian fluid,based on Navier-Stokes(N-S)theory,the movement of the interfaces of air-water and water-sediment water was tracked by the volume of fluid(VOF)method.The velocity field of sediment water was simulated by considering the effect of water waves.The results show that the movement of sediment water is very different from that of sea water,which provides a solid basis for understanding the resuspension and settlement of sediment and the formation of bottom stripe,and the VOF method can trace the movement of the two interfaces simultaneously;the movement of the air-water interface has a strong effect on that of the water-sediment water interface,while the effect of the water-sediment water interface movement on the air-water interface is not obvious.
