The two one-state-variable, rate- and state-dependent friction laws, i.e., the slip and slowness laws, are com- pared on the basis of dynamical behavior of a one-degree-of-freedom spring-slider model through numerical...The two one-state-variable, rate- and state-dependent friction laws, i.e., the slip and slowness laws, are com- pared on the basis of dynamical behavior of a one-degree-of-freedom spring-slider model through numerical simulations. Results show that two (normalized) model parameters, i.e., A (the normalized characteristic slip distance) and β-α (the difference in two normalized parameters of friction laws), control the solutions. From given values of △, β, and α, for the slowness laws, the solution exists and the unique non-zero fixed point is stable when △〉(β-α), yet not when △ 〈(β-α). For the slip law, the solution exists for large ranges of model parameters and the number and stability of the non-zero fixed points change from one case to another. Results suggest that the slip law is more appropriate for controlling earthquake dynamics than the slowness law.展开更多
The correlation of the scaled energy,e = Es/ Mo, versus earthquake magnitude, Ms, is studied based on two models: (1) Model 1 based on the use of the time function of the average displacements, with a ω^-2 source ...The correlation of the scaled energy,e = Es/ Mo, versus earthquake magnitude, Ms, is studied based on two models: (1) Model 1 based on the use of the time function of the average displacements, with a ω^-2 source spectrum, across a fault plane; and (2) Model 2 based on the use of the time function of the average displacements, with a ω^-3 source spectrum, across a fault plane. For the second model, there are two cases: (a) As ζ= T, where r is the rise time and T the rupture time, lg(e) - -Ms; and (b) As ζ 〈〈 T, lg(e)- -(1/2)Ms. The second model leads to a negative value of e. This means that Model 2 cannot work for studying the present problem. The results obtained from Model 1 suggest that the source model is a factor, yet not a unique one, in controlling the correlation of e versus Ms.展开更多
During the ruptures of an earthquake, the strain energy, AE, will be transferred into, at least, three parts, i.e., the seismic radiation energy (Es), fracture energy (Eg), and frictional energy (Ef), that is, A...During the ruptures of an earthquake, the strain energy, AE, will be transferred into, at least, three parts, i.e., the seismic radiation energy (Es), fracture energy (Eg), and frictional energy (Ef), that is, AE = Es + Eg + El. Friction, which is represented by a velocity- and state-de- pendent friction law by some researchers, controls the three parts. One of the main parameters of the law is the char- acteristic slip displacement, De. It is significant and nec- essary to evaluate the reliable value of Dc from observed and inverted seismic data. Since Dc controls the radiation efficiency, ηR = Es/(Es + Eg), the value of qR is a good constraint of estimating Dc. Integrating observed data and inverted results of source parameters from recorded seis- mograms, the values of Es and Eg of an earthquake can be measured, thus leading to the value of ηR. The constraint used to estimate the reliable value of Dc will be described in this work. An example of estimates of Dc based on the observed and inverted values of source parameters of the September 20, 1999 Ms 7.6 Chi-Chi (Ji-Ji), Taiwan region, earthquake will be presented.展开更多
基金supported by Academia Sinica (Taipei) and Science Council (Grant NSC96-2116-M-001-012-MY3).
文摘The two one-state-variable, rate- and state-dependent friction laws, i.e., the slip and slowness laws, are com- pared on the basis of dynamical behavior of a one-degree-of-freedom spring-slider model through numerical simulations. Results show that two (normalized) model parameters, i.e., A (the normalized characteristic slip distance) and β-α (the difference in two normalized parameters of friction laws), control the solutions. From given values of △, β, and α, for the slowness laws, the solution exists and the unique non-zero fixed point is stable when △〉(β-α), yet not when △ 〈(β-α). For the slip law, the solution exists for large ranges of model parameters and the number and stability of the non-zero fixed points change from one case to another. Results suggest that the slip law is more appropriate for controlling earthquake dynamics than the slowness law.
基金sponsored by Academia Sinica and the National Science Council(under Grant No.NSC101-2119-M-001-01)
文摘The correlation of the scaled energy,e = Es/ Mo, versus earthquake magnitude, Ms, is studied based on two models: (1) Model 1 based on the use of the time function of the average displacements, with a ω^-2 source spectrum, across a fault plane; and (2) Model 2 based on the use of the time function of the average displacements, with a ω^-3 source spectrum, across a fault plane. For the second model, there are two cases: (a) As ζ= T, where r is the rise time and T the rupture time, lg(e) - -Ms; and (b) As ζ 〈〈 T, lg(e)- -(1/2)Ms. The second model leads to a negative value of e. This means that Model 2 cannot work for studying the present problem. The results obtained from Model 1 suggest that the source model is a factor, yet not a unique one, in controlling the correlation of e versus Ms.
基金financially supported by Academia Sinica and Ministry of Science and Technology under Grand Nos.of MOST 103-2116-M-001-010 and MOST 104-2116-M001-007
文摘During the ruptures of an earthquake, the strain energy, AE, will be transferred into, at least, three parts, i.e., the seismic radiation energy (Es), fracture energy (Eg), and frictional energy (Ef), that is, AE = Es + Eg + El. Friction, which is represented by a velocity- and state-de- pendent friction law by some researchers, controls the three parts. One of the main parameters of the law is the char- acteristic slip displacement, De. It is significant and nec- essary to evaluate the reliable value of Dc from observed and inverted seismic data. Since Dc controls the radiation efficiency, ηR = Es/(Es + Eg), the value of qR is a good constraint of estimating Dc. Integrating observed data and inverted results of source parameters from recorded seis- mograms, the values of Es and Eg of an earthquake can be measured, thus leading to the value of ηR. The constraint used to estimate the reliable value of Dc will be described in this work. An example of estimates of Dc based on the observed and inverted values of source parameters of the September 20, 1999 Ms 7.6 Chi-Chi (Ji-Ji), Taiwan region, earthquake will be presented.