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 opinions of two papers carried in the journal "Seismology and Geology" are discussed in the paper.One is that the Tangshan fault is a high-angle,west-dipping and thrust with strike-slip fault.The other i...The opinions of two papers carried in the journal "Seismology and Geology" are discussed in the paper.One is that the Tangshan fault is a high-angle,west-dipping and thrust with strike-slip fault.The other is that the Fuzhuang-Xihe fault distributed on the east side of Tangshan city is the seismogenic fault that caused the Tangshan earthquake.For the former opinion,it needs to explain the relationship between the active style of the thrust Tangshan fault and the formation genesis of a Quaternary depression along the west side of Tangshan city.For the latter opinion,if the Fuzhuang-Xihe fault is the seismogenic fault of the Tangshan earthquake,it needs to explain the genesis relationship between this west-dip slip fault zone and the strike-slip surface fissure zone that extends through Tangshan city.And it needs more evidence exclude the possibility that the surface rupture belongs to the rupturing of a secondary structure.This paper suggests doing more work on the active fault that controls the Caobo Quaternary depression.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.
文摘The opinions of two papers carried in the journal "Seismology and Geology" are discussed in the paper.One is that the Tangshan fault is a high-angle,west-dipping and thrust with strike-slip fault.The other is that the Fuzhuang-Xihe fault distributed on the east side of Tangshan city is the seismogenic fault that caused the Tangshan earthquake.For the former opinion,it needs to explain the relationship between the active style of the thrust Tangshan fault and the formation genesis of a Quaternary depression along the west side of Tangshan city.For the latter opinion,if the Fuzhuang-Xihe fault is the seismogenic fault of the Tangshan earthquake,it needs to explain the genesis relationship between this west-dip slip fault zone and the strike-slip surface fissure zone that extends through Tangshan city.And it needs more evidence exclude the possibility that the surface rupture belongs to the rupturing of a secondary structure.This paper suggests doing more work on the active fault that controls the Caobo Quaternary depression.
